Research ArticleSoilWaterCharacteristics ofGleysols in theBamenda (Cameroon)Wetlands and Implications for AgriculturalManagement Strategies

Alice Mufur Magha1 Primus Azinwi Tamfuh 23 Lionelle Estelle Mamdem4

Marie Christy Shey Yefon3 Bertrand Kenzong2 and Dieudonne Bitom2

1Department of Geology Higher Teacher Training College e University of Bamenda PO Box 39 Bambili Cameroon2Department of Soil Science University of Dschang PO Box 222 Dschang Cameroon3Department of Mining and Mineral Engineering National Higher Polytechnic Institute University of Bamenda PO Box 39Bambili Cameroon4Department of Earth Sciences University of Ngaoundere PO Box 454 Ngaoundere Cameroon

Correspondence should be addressed to Primus Azinwi Tamfuh aprimus20yahoocouk

Received 28 November 2020 Revised 23 February 2021 Accepted 27 February 2021 Published 13 March 2021

Academic Editor Evgeny Abakumov

Copyright copy 2021 Alice Mufur Magha et al is is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

Water budgeting in agriculture requires local soil moisture information as crops dependmainly onmoisture available at root levele present paper aims to evaluate the soil moisture characteristics of Gleysols in the Bamenda (Cameroon) wetlands and toevaluate the link between soil moisture content and selected soil characteristics affecting crop production e work wasconducted in the field and laboratory and data were analyzed by simple descriptive statistics e main results showed that thesoils had a silty clayey to clayey texture high bulk density high soil organic carbon content and high soil organic carbon stockse big difference between moisture contents at wilting point and at field capacity testified to very high plant-available watercontent Also the soils displayed very high contents of readily available water and water storage contents e soil moisturecharacteristics give sigmoid curves and enabled noting that the Gleysols attain their full water saturation at a range of 5768 to9170 of dry soil Clay and SOC contents show a significant positive correlation with most of the soil moisture characteristicsindicating that these soil properties are important for soil water retention Particle density coarse fragments and sand contentscorrelated negatively with the soil moisture characteristics suggesting that they decrease soil water-holding capacitye principalcomponent analysis (PCA) enabled reducing 17 variables described to only three principal components (PCs) explaining 7373of the total variance the first PC alone expressed 4512 of the total variance associating clay SOC and six soil moisturecharacteristics thus portraying a deep correlation between these eight variables Construction of contoured ditches deep tillageand raised ridges management techniques during the rainy season while channeling water from nearby water bodies into thefarmland opportunity cropping and usage of water cans and other irrigation strategies are used during the dry season to combatwater constraints

1 Introduction

Soil water information is necessary for rainfall partitionestablishment of irrigation schedules and partitioning of netradiation [1 2] e response of soil water properties is a keyindicator of the impact of agricultural management on themovement of water and chemicals through the soil [3]

Wetlands are temporarily or permanently flooded areaswhere the soils are water-saturated and waterlogging iscommon [4]

Gleysols typical of wetlands are characterized by re-duction or localized segregation of iron due to temporary orpermanent waterlogging causing anaerobic conditions [5]ese soils occur where hydrological conditions controlled

HindawiApplied and Environmental Soil ScienceVolume 2021 Article ID 6643208 15 pageshttpsdoiorg10115520216643208

by abundant rainfall gentle slope low landscape position orimpermeable soils lead to soil surface saturation by water fora sufficiently long period enough for waterlogging to occur[6]Water fluctuations at depths control the chemical andorbiological processes within both the water column and soilparticles [7 8] Wetland soils are unique among soils andpossess morphological physical and chemical propertiesthat readily distinguish them from upland soils [9 10]Considerable studies have been carried out to understandthe moisture characteristics of tropical soils [11ndash13]However little effort has been dedicated to the under-standing of Gleysols water characteristics in tropical wetlandecosystems

Wetlands cover approximately 6 of the Earthrsquos surfacein all climates [12] Although these wetland soils may beminor inclusions in terms of their spatial distribution theyare important contributors to agricultural productivity [5]ese areas contain about 35 of global terrestrial carboncritical to agricultural production and climate change mit-igation [14]e Ramsar Convention onWetland Protection[4] highlights key information on wetlands and climatechange mitigation and adaptation such as the assessment ofcarbon uptake and storage is has revealed that contin-uous loss and degradation of wetlands results in significantlosses of soil organic carbon stock (SOCS) to the atmosphere[14]

According to the Ramsar Sites Information Service [15]there are seven Ramsar sites in Cameroon (e Barombi-Mbo Crater Lake the Rio Del Rey Estuaries Camerooniansection of the Ntem River Cameroonian Section of theSangha River Cameroonian section of the Lake ChadWaza-Logone floodplain and the Ebogo Humid Zone)covering a total surface area of 82706 km2 e positions ofthe sites are shown in Figure 1 Many Cameroonian vastwetlands have not yet been studied in detail and thus remainunselected as Ramsar sites such as the Limbe and Wouriestuaries (Littoral Cameroon) the Nun River valley theMenchumMezam Valley (Northwest Cameroon) theSantchou Floodplains (West Cameroon) amongst otherse study and selection of these wetlands as Ramsar Sites inCameroon could contribute to one of the goals of the RamsarConventionrsquos strategic plan [4] which was to attain aprotected area of 250 million hectares since 2015

In Bamenda Town (Northwest Cameroon) major wet-lands occur along the Mezam River floodplains and itstributaries especially in Ngomgham Mulang NteneforBelow Foncha and Mile 4 Nkwen [15ndash17] e lawlessoccupation of wetlands has intensified recently due to de-mographic pressure as soils in these areas are very fertile andsupport year-round market gardening [18 19] Some humanactivities in these wetlands (land reclamation waste disposaldeforestation agriculture industrialization etc) have led tothe degradation of most of these ecosystems [20]

e main agricultural practice in Bamenda wetlands ismarket gardening and dry season maize farming [21] Inthese wetland soils Asongwe et al [21] reported thespatial variability of physicochemical properties of soilsunder vegetable Mofor et al [22] focused on trace ele-ment status and environmental implications on soils and

Zea mays near dumpsites Land preparation for cropproduction is conducted under submerged conditionsgenerating a massive plough layer which affects man-agement strategies and crop performance Works thatconcern the moisture characteristics of those Gleysols areinexistent despite the fact that soil water is the majorfactor affecting agriculture in these areas Some questionthus require answers what are the moisture character-istics of the Bamenda wetland soils is there a relationshipbetween the moisture characteristics and the other soilproperties what are the best management strategies of thesoils for sustainable agriculture

e aim of the present study was to determine themoisture characteristics of the Bamenda Gleysols and toestablish a link between moisture characteristics andselected soil characteristics as well as to recommend bestmanagement strategies of the Gleysols for crop produc-tion e results obtained will enable to support theconservation restoration and management of wetlandsoils and to create social awareness on the importance ofwetlands in line with one of the goals of the RamsarConventionrsquos strategic plan

2 Materials and Methods

21 Study Site Description e Bamenda municipality islocated on the northwest flank of the Bamenda Mountainwhich is a stratovolcano situated along the CameroonVolcanic Line [23 24] It extends from longitude 10deg 08prime to10deg 12prime E and latitude 5deg 55prime to 6deg 00prime N and at an altitude of2621m above sea level (Figure 2) e town covers a surfacearea of 7123 km2 e climate is the Cameroonian-typeequatorial climate characterized by two seasons a long rainyseason of 7 months (April to October) and a short dry seasonof 5 months (November toMarch)emean annual rainfallis 2670mm and the average annual air temperature is 25degCe Mezam River draining the town is a second-orderperennial stream fed by several other small streams most ofwhich originate from the Bamenda escarpments ey forma dense dendritic patternemajor winds affecting this areaare Harmattan (that bring the dry season) and the monsoon(that brings rain) Rainfall is heavy and often destructivee vegetation is the Guinea Savannah type with shortstunted trees (Bamenda Grassfields) and short deciduoustrees meanwhile Raffia palms grow in the swampy valleyse town is located along the Cameroon Volcanic Line andexhibits two very distinct relief environments the high lavaplateau or Up Station (1400m above sea level) and the lowplateau or Downtown (1200m above sea level) separated byan escarpment of about 150m Geologically Bamenda isunderlain by Precambrian granite-gneiss basement andoverlain by volcanic rocks like basalts trachyte dolerite andignimbrites [25] sedimentary silty clays of the Mezam Riverfloodplains [26] e dominant soils are Ferralsols withminor Lithosols on the hillslopes and Gleysols in theswampy valleys [9 21] Farming is the main activity of theinhabitants and it is mostly crop-based farming pastoralnomadism mixed crop-livestock and secondary and tertiaryactivities [21]

2 Applied and Environmental Soil Science

22 Methodology and Analytics Twenty (20) samplingpoints representative of the Bamenda Wetlands were se-lected within five neighborhoods (Mulang NgomghamBelow Foncha and Mile 4 Nkwen) in the Bamenda mu-nicipality wetlands (Figure 2) One sample was collected perpoint at 0ndash50 cm depth (effective rooting zone for a majorityof crops cultivated in this area green beans onion lickshuckleberry tomatoes carrot etc) Disturbed and undis-turbed samples were taken for three repetitions e total

area sampled was about 30 km2 Sampling was conducted inthe dry season in November 2019 when the water level in thearea was low Soil samples collected were packed in air-tiedplastic bags and taken to the laboratory for analysis

In the laboratory the bulk density (Db) was determinedby paraffin coating method and particle density (Dp) wasmeasured by pycnometer method Porosity (p) was deducedfrom the particle and bulk densities e particle size dis-tribution was measured by Robinsonrsquos pipette method and

10deg00prime

Federal republic ofnigeria

Republic of

Chad

Cent

rafri

can

repu

blic

10deg15prime

10deg00prime

EqGuinea Gabon

E

6

3

7

S

2

5

CE

LT

SW W

NW

AD

N

EN

1

4

N

NtemSangha

Nyong

Logone

Peoplersquos rep ofCongo

10deg0

0prime05

deg00prime

10deg0

0prime05

deg00prime

10deg15prime

River

Regional boundary

Lakeocean

Figure 1 Location of the Ramsar sites in Cameroon [15] Sites are numbered from youngest to oldest based designation date (1) Waza-Logone floodplain (2) Barombi-Mbo Lake (3) Cameroon section of the Sangha River (4) Cameroon section of Lake Chad (5) Rio Del ReyEstuary (6) Cameroon section of the Ntem River (7) Ebogo Humid Zone EN Extreme North Region NW Northwest Region N NorthRegion AD Adamawa Region CE Centre Region E East Region LT Littoral Region S South Region SW Southwest Region W WestRegion

Applied and Environmental Soil Science 3

10deg00prime 10deg15prime

10deg00prime

km

0 155 310 620

10deg15prime

10deg0

0prime05

deg00prime

Federal republic ofnigeria

Republic of

Chad

Cent

rafri

can

repu

blic

EqGuinea Gabon

E

S

CE

LT

Atlanticocean

SW WNW

AD

N

EN

N

Peoplersquos repof Congo

Study site

(a)

10deg00prime 10deg10primeTo Bafoussam

To M

amfe

To K

umbo

10deg20prime

km

189450

10deg00prime 10deg10prime 10deg20prime

6deg20

prime6deg

10prime

6deg00

prime5deg

50prime

5deg40

prime

MENTCHUMBUI

BOYO

MEZAM

Tubah

Bafut

MOMO

LEBIALEM BAMBOUTOS

NG

OKE

TUN

JIA

Bali

Santa

Bamenda

Tarred road

Secondary roads

(b)

N

10deg8prime20PrimeE

6deg0prime

0PrimeN

5deg59

prime10

PrimeN

5deg58

prime20

PrimeN

5deg57

prime30

PrimeN

6deg0prime

0PrimeN

5deg59

prime10

PrimeN

5deg58

prime20

PrimeN

5deg57

prime30

PrimeN

10deg9prime10PrimeE 10deg10prime10PrimeE 10deg10prime50PrimeE

10deg8prime20PrimeE

0 04 08 16 24

10deg9prime10PrimeE 10deg10prime10PrimeE

Coordinate system WGS 84 UTM zone 32 N

10deg10prime50PrimeE

Untarred roads

Water bodles

Study area

Neighbourhood

Sample points

National road

Tarred roads

High 1787Low 1170

(c)

Figure 2 Location maps of the study area (a) location of Mezam Division in Cameroon (b) location of Bamenda in Mezam Division(c) studied site map with sampling points

4 Applied and Environmental Soil Science

SOC was analyzed by Walkley-Black method All theseanalyses were conducted according to the procedures de-scribed in [27]

e soil organic carbon stock (SOCS) was calculatedaccording to the following equation [14]

SOCS Mg middot haminus11113872 1113873 SOC content times BD times d(

times 1 minus δ2mm( 1113857 times 101113857(1)

where SOC is the organic carbon content (g kgminus1) d is thesoil layer thickness (m) δ2mm is the coarse fragments(gt2mm diameter) content () and BD is the soil bulkdensity (Mgmiddotmminus3)

e hygroscopic water content was calculated by usingthe weight loss of an air-dry sample after subjecting it to anoven temperature of 105degC for 24 hours [28] To determinethe soil water content at field capacity (FC) the soil coreswere first saturated and their soil water content at 33 kPa wasmeasured using the tension tables [29] e permanentwilting point (WP) water content at 1500 kPa suction wasmeasured on the subsample using a pressure plate apparatus[30] e capillary water (CW) was calculated as the dif-ference between the hygroscopic water and the field capacitywater content [31] e unavailable water content (UW) wasobtained as the difference between the capillary water andwater content permanent wilting point [32] Gravity water(GW) was obtained as the difference between total porosityand capillary water e air content (AC) was calculated asthe difference between the total porosity and the moisturecontent at field capacity [5] e available water reserve(AWR) was calculated as the difference between the FC andWP [33]

e available water content (AWC) was calculatedaccording to the following equation [5]

AWC Db times E times(FC minus WP)

1001113888 1113889 (2)

where FC is the moisture content at field capacity () WP isthe moisture content at permanent wilting point () E is thedepth of the soil layer (in dm) andDb is the soil bulk densityin gmiddotcmminus3

e readily available water content (RAW) was esti-mated as the product of the management allowed deficiency(approximately 23 for wetland soils) and the AWC [32]

e water-holding capacity (WHC) was calculated as theAWC multiplied by 2 according to GEPPA [34]

Before calculating the infiltration depth (in dmmiddotmminus1) ineach of the soil layers the volumetric water content wascalculated according to the following equation [35]

Vw FC middotDb

Dw

1113888 1113889 (3)

where Vw is the volumetric water content (at field capacity)in FC is the gravimetric water content at field capacity Db isthe soil bulk density and Dw is the density of water(1 gmiddotcmminus3) e infiltration depth of the soil layer was thenobtained as the product of Vw and the soil depth (in dm)[35]

23 Statistical Analyses Pearson linear correlation test andprincipal component analysis (PCA) enabled establishingthe relationship between soil characteristics

3 Results

31 Soil Characteristics e characteristics of the BamendaGleysols sampled in the five different neighborhoods arecompiled in Table 1 meanwhile results of summary sta-tistical analysis of these soil characteristics are presented inTable 2 Soil characteristics such as particle density bulkdensity total porosity and particle distribution did not varymuch amongst the different sites e SOC and SOCS werealso very high for all the studied sites but the ranges of valuesamongst the different sites differed very lightly (Table 1)eparticle density of the soils ranged between 23 and25 gmiddotcmminus3 with a mean of 236 gmiddotcmminus3 and a very lowcoefficient of variation (CV) of 286 (Table 2) About 45of the samples showed a low particle density of 23 gcm3

while the rest ranged from 24 to 25 gmiddotcmminus3e bulk densityranged from 13 to 16 gmiddotcmminus3 with a mean of 143 g cmminus3

and a very low CV e total porosity varied from 40 to4348 with a mean of 4167 and changed very little fromone locality to another (CV 30) e soils showed onlytwo grain size classes clayey to clayey loam texture (Fig-ure 3) e clayey fraction was moderately variable(CV 210) and 900 of the values fell between 30 and450 clay content e fine silt contents ranged from 80 to290 with a high CV e coarse silt contents ranged from100 to 220 with an average of 1790 and amoderate CVe fine sand fraction varied from 60 to 220 with a meanof 136 and a CV of 320 e coarse sand content fol-lowed almost the same trend as fine sand ranging from 9 to22 giving a mean of 151 and CV of 29e contents incoarse fragment varied from 3 to 25 with an average valueof 12 and a high CVe sandsilt ratio fluctuated between055 and 196 portraying a moderate coefficient of variationof 34e siltclay ratio varied between 055 and 190 witha low CV of 105 e (silt + sand)-to-total earth ratios ofthe Gleysols ranged between 5229 and 7573 e SOCfluctuated from 567 to 1945 with an average of 1366and a CV of 3032 e SOCS varied between 25163 and80493Mgmiddothaminus1 with a mean of 55330Mgmiddothaminus1 and amoderate CV

e soilmoisture characteristics are compiled in Table 3 andthe results of summary statistical analysis of moisture retentioncharacteristics are presented in Table 4 e hygroscopic watercontent varied between 720 and 2303 with amean of 1372and a CV of 360 e WP (pF31500kPa) ranged between2214 and 5886 with a mean of 448 and CV of 250emoisture content at field capacity FC (pF3 33kPa) changedbetween 4816 and 7534 showing a mean of 670 and a CVof 110 e AWR ranged between 1113 and 458 itsmean value stood at 222 and the CVwas 460eAWC ofthe studied soil varied between 21583 and 42361mmm with amean value of 3397 and a CV of 180e RAW varied from28921 to 56764mmm with a mean of 45540 and a CV of180e CWwas within the range of 2904 to 570 and themost frequent values appeared between 39 and 570 while the

Applied and Environmental Soil Science 5

Tabl

e1

Geographiccoordinatesanddetailedsoilph

ysical

characteristicsandorganicmattercontento

fBam

enda

soils

(0ndash5

0cm

depth)

S no

Long

ELatN

Altitude

Site

Particle

density

Bulk

density

Porosity

Particle

sizedistribu

tion

Coarse

fragments

Silt

sand

ratio

Silt

clay

ratio

YSO

CSO

CS

Fine

sand

Coarse

sand

Fine silt

Coarse

silt

Clay

(m)

mdashgmiddotcm

minus3

gmiddotcm

minus3

mdash

mdashmdash

Mgmiddotha

minus1

110165386

5988697

1209

Mile

4Nkw

en

24

14

4167

1219

1920

3011

123

123

6216

1030

42516

210172271

5989171

1203

24

15

4167

2122

818

319

067

067

5229

1296

58320

310175703

5988982

1208

25

15

4000

119

1721

4212

078

078

7143

1823

80493

410158177

5980301

1101

Below

Foncha

23

15

4348

1118

2021

305

128

128

6762

1621

72945

510149519

5983058

1103

23

14

4348

2212

1020

3612

087

087

5893

1864

78288

610145689

5978807

1101

24

13

4167

1710

1619

3815

092

092

6348

1621

63219

710140556

5986379

1103

24

15

4167

812

2020

4017

100

100

6838

1296

57381

810164556

5985557

1104

Mulang

24

15

4167

1219

2220

2712

193

193

6161

567

25163

910182545

5985485

1103

24

13

4167

1812

1522

3312

114

114

6250

1418

54384

1010135003

5985485

1104

23

14

4348

613

912

6021

058

058

6694

1742

71906

111013429

5979775

1104

24

16

4167

1221

1311

4312

056

056

5982

810

38149

1210159417

5975206

1102

23

14

4348

1222

919

379

060

060

6019

1418

58544

1310154991

5983772

1102

Ngomgh

am

25

15

4000

1317

2920

2912

196

196

6500

770

34650

1410144283

597592

1103

23

14

4348

1112

1120

4614

055

055

6754

1823

75211

1510139715

5990339

1102

24

15

4167

913

1916

433

071

071

7573

1134

50117

161016941

5987627

1102

23

16

4348

1113

1615

407

072

072

6961

1621

76563

1710161844

5968353

1103

24

15

4167

1222

2710

2925

162

162

5280

770

34023

1810145996

5981488

1105

Ntamulun

g23

15

4348

159

1220

449

078

078

6972

1580

69870

1910134718

5992481

1106

23

14

4348

1914

1220

3521

093

093

5537

1175

48496

2010178336

599321

1104

23

14

4348

1912

1015

443

068

068

6699

1945

80277

Yslit+

clayto

tale

arth

times100

where

totale

arth

sand

+silt+

clay

+coarse

fragments

6 Applied and Environmental Soil Science

mean value stood at 4808 and the CV was 140 e UWvaried between 244 and 2759emean value of unavailablewater of 848 was low showing a low CV at 510eWHCvaried between 43171 and 84722mmm meanwhile the meanvalues attained 67970mmm and the CV was 18 egravitational water content of the Bamendawetland soils rangedfrom 072 to 1352 with amean of 746 and a CVof 5471e infiltration depth (D) appeared between 265dmmiddotmminus1 and444dmmiddotmminus1 and the mean and CV were respectively383dmmiddotmminus1 and 12e natural air content of the soils at FCoscillated between 649 and 3186 with a mean of 2476 and aCV of 28

32 Correlation and Principal Component Analysis of the SoilCharacteristics ere was a positive correlation betweensand content and Dp and a negative correlation between DPand clay content (Table 5) Db was correlating negatively

with SOC while sand and clay contents showed a significantnegative correlation Clay and SOC contents showed asignificant positive correlation e coarse fragments con-tents correlated negatively with SOC and Db but positivelywith Db e siltclay ratio showed a significant positivecorrelation with Db Dp as well as sand silt and rockfragment contents but correlated negatively with SOC andclay contents Among the soil properties SOCS was posi-tively correlated with Db clay and silt-to-clay ratio butnegatively correlated with Dp sand silt coarse fragmentsand SOC contents No significant correlation was observedbetween the soil moisture characteristics and siltclay ratioe SOCS showed a positive correlation with FC PW CWand WHC and a negative correlation with HW AWR andUW

e analysis of linear correlation of soil moisturecharacteristics revealed that WP showed a significant pos-itive correlation with AWC and RAW and a significantnegative correlation with AWR and UW (Table 6) Also FCshowed a positive correlation with AWC RAW WHC andinfiltration depth (D) of the soil layer e AWR showed avery significant negative correlation with AWC RAW andWHC e AWC displayed a strong negative correlationwith UW while RAW displayed a strong negative corre-lation with UW e CW revealed a strong positive cor-relation with D Also UW showed a significant negativecorrelation with WHC

e PCA enabled observing a reduction of the 17original variables described to only three principal com-ponents (PC1 PC2 and PC3) explaining 7373 of the totalvariance explained (Table 7) us PC1 explained 4512 ofthe total variance and revealed significant loadings on WPAWR AWC RAW UW WHC clay and SOC while PC2expressed 1893 of the total variance and showed signif-icant loadings at FC CW and D (Figure 4) PC3 expressedsignificant loadings withDb and sand with a total variance of968 e PC1 was named the soil water retention factorbecause of a high factor loading of moisture characteristicswith soil colloids (clay and organic carbon) e PC2 wasreferred to as the available water factor because of high factorloading between available water capillary water and infil-tration depth e PC3 was denoted the soil compactionfactor as sand and bulk density affect soil porosity

Table 2 Summary statistics of the soil physical characteristics and organic matter content (n 20)

Parameters Dp Db PorosityParticle size distribution

Coarsefragments

Sandsiltratio

Siltclayratio

SOC SOCSFinesand

Coarsesand

Finesilt

Coarsesilt Clay

gmiddotcmminus3 gmiddotcmminus3 Mgmiddothaminus1

Minimum 230 130 4000 600 900 800 1000 2700 300 050 055 567 25163Maximum 250 160 4348 2200 2200 2900 2200 6000 2500 165 196 1945 80493Mean 236 145 4232 1360 1510 1570 1790 3790 1210 090 096 1366 59368SD 0067 0083 119 439 449 597 355 792 57700 031 044 414 17261CV 286 567 280 3200 2900 3850 19 21 4789 3400 105 3032 2907Skew 0549 minus0176 minus0464 0477 0400 0720 minus1197 0957 0521 099 1390 minus0450 minus052Kurtosis minus0548 minus0212 minus765 minus0575 minus129 minus008 027 171 027 056 098 minus092 minus085K-S stat 0284 0257 0287 0238 0226 0133 0269 0119 0203 0122 0210 0147 0282Dp particle density Db bulk density CV coefficient of variation SD standard deviation K-S stat KolmogorovndashSmirnov statistics

100 0

10

20

30

40

50

60

70

80

90

100

90

80

70

60

50

40

30

20

10

0100 90 80 70 60

sand

cl

ay

silt

50 40 30 20 10 0

1

2

3

4

5

67

8 9101112 13

Figure 3 Textural classes of the Bamenda Gleysols according to theUnited States Department of Agriculture textural classi-ficationmdashclassification according to the Soil Science Division Staff[6] (1) heavy clay (2) clay (3) sandy clay (4) clayey loam (5) siltyclayey (6) silty clay loam (7) sandy clay loam (8) loam (9) siltyloam (10) sandy loam (11) loamy sand (12) sand (13) loam

Applied and Environmental Soil Science 7

33 Soil Water Characteristic Curves Soil moisture char-acteristic curves enabled establishing the relationship be-tween the volumetric water content and soil matric potentialof the studied soil (Figure 5) using water retention data(Table 8) e curves revealed a sigmoid shape which slopedgently from the HW to UW steepened more from UW to

AW and became gentle from gravity water to complete poresaturation e Gleysols of Mile 4 Nkwen showed the lowestwater retention curve while those of Ngomgham displayedthe highest ones (Figure 5) e soils attained full watersaturation (HW+AWC+GW+AC) at a range of 5768 ofdry soil (Mile 4 Nkwen) to 9170 of dry soil (Ngomgham)

Table 3 Moisture characteristics of the Gleysols from the Bamenda Wetlands (n 20)

S no Site HW WP FC AWR AWC RAW CW UW GW AC WHC D() () () () (mmm) (mmm) (mmm) (mmm) (mmm) () (mmm) (dmm)

1Mile 4 Nkwen

912 366 4816 1156 28267 37878 2904 244 1263 649 56534 2652 72 4152 566 1508 33127 4439 394 788 227 1493 66253 3343 82 5606 6719 1113 4181 56025 4699 293 699 2719 83619 3974

Below Foncha

1776 4842 698 2138 37164 49799 5204 362 856 2632 74327 4125 1222 5568 7258 169 38754 5193 5436 468 1088 291 77507 46 222 4762 7328 2566 31767 42567 5108 346 941 3161 63533 3757 134 4592 6941 2349 35932 48148 4601 1009 434 2774 71863 418

Mulang

1232 2214 572 3506 21583 28921 4488 2274 321 1553 43166 3389 1088 4556 6247 1691 30824 41304 4559 603 392 208 61648 3210 743 5884 7267 1383 4076 54618 5324 64 976 2919 8152 40111 158 334 7049 3709 30391 40723 5469 2129 1302 2882 60781 44412 1221 4716 6262 1546 34147 45757 4141 325 207 1914 68294 34513

Ngomgham

1535 254 6834 4294 23436 31404 4999 2759 999 2834 46871 40414 1311 5886 7534 1648 40688 54522 5523 337 1175 3186 81376 41515 221 4228 6449 2221 33792 45281 4239 011 072 2282 67583 38116 939 5242 6726 1484 42361 56764 4887 545 539 2378 84722 42417 2302 27 728 458 24456 3277 4978 2278 811 3113 48911 4318

Ntamulung978 532 7324 2004 40257 53944 5346 1026 998 2976 80513 418

19 1567 415 6192 2042 31032 41583 4625 475 277 1844 62064 40420 1721 565 7421 1771 39157 5247 5700 050 1352 3073 78314 341

Table 4 Summary statistics of the soil moisture characteristics in the Bamenda wetlands (n 20)

Parameters HW WP FC AWR AWC RAW CW UW WHC D GW AC() () () () (mmm) (mmm) () () (mmm) (dmm) () ()

Minimum 720 2214 4816 1113 21583 28921 2904 011 43166 265 072 649Maximum 2302 5886 7534 4580 42361 56764 5700 2759 84722 4 44 1352 3186Mean 1372 4480 6700 2220 33985 45540 4809 848 67970 383 746 2476SD 487 1116 709 1016 6287 8424 665 825 12573 045 408 689CV 3600 2500 1100 4600 1800 1800 1400 9700 1800 1200 5500 2800Skew 059 minus066 minus115 127 minus048 minus048 minus121 133 minus048 minus106 minus014 minus119Kurtosis minus053 minus045 110 063 minus070 minus070 216 047 minus070 081 minus140 097K-S stat 013 013 016 020 013 013 012 025 013 022 013 020HW hygroscopic water WP permanent wilting point FC field capacity AWR available water reserve AWC available water content RAW readilyavailable water CW capillary water UW unavailable water WHC water-holding capacity D weighting depth AC air content GW gravity water CVcoefficient of variation SD standard deviation K-S stat KolmogorovndashSmirnov statistics

Table 5 Correlation amongst soil physical characteristics and soil organic carbon

Soil properties Dp Db Sand Silt Clay RF SOC Siltclay ratio SOCSDp 1 mdash mdash mdash mdash mdash mdash mdashDb 02 1 mdash mdash mdash mdash mdash mdash mdashSand 038 minus012 1 mdash mdash mdash mdash mdash mdashSilt 022 minus002 minus032 1 mdash mdash mdash mdashClay minus052lowast minus011 minus063lowastlowast minus041 1 mdash mdash mdash mdashRF 011 minus02 minus025 024 minus008 1 mdash mdash mdashSOC minus049lowast minus04 minus031 minus031 069lowastlowast minus026 1 mdash mdashSiltclay ratio 046lowast 01 017 080lowastlowast minus084lowastlowast 022 minus064lowastlowast 1 mdashSOCS minus048lowast 049lowast minus036 minus040 053lowastlowast minus032 minus065lowastlowast 098lowastlowast 100lowastCorrelation is significant at the 005 level lowastlowastcorrelation is significant at the 001 level

8 Applied and Environmental Soil Science

e height of the water characteristic curves shows a meanincreasing trend such that Ngomghamgt belowFonchagtMulanggtNtamulunggtMile 4 Nkwen

4 Discussion

41 Soil Moisture Storage Capacity of Gleysols as Affected byPhysical Properties and SOC e Gleysols of the Bamendawetlands were reddish brown wet and waterlogged with

reddish yellow and blue patches in the more waterloggedareas e surface aspect of the studied Gleysols is shown inFigure 6 ese properties are common to all wetland soils[28] e massive structure and high density of these soilscan be attributed to high clay content e high clay contentin turn made the soils stick to farm tools e sandsilt ratiois an index of weathering intensity according to Sharma et al[36] All the ratio values were greater than 045 typical ofmoderate weather e siltclay ratio of the Gleysols wasgt015 indicating that the soils are relatively young or gt020portraying a high degree of weathering potential [37] eseindices agreed with values of alluvial floodplain Gleysols[13]

e plant-available water content of the BamendaGleysols was very high according to GEPPA [34] Such high

Table 6 Pearson linear correlation coefficients amongst soil moisture characteristics (n 20)

Soil properties HW WP FC AWR AWC RAW CW UW WHC DHW 100 mdash mdash mdash mdash mdash mdash mdash mdash mdashWP minus032 100 mdash mdash mdash mdash mdash mdash mdash mdashFC 036 045 100 mdash mdash mdash mdash mdash mdash mdashAWR 059lowast minus078lowastlowast 020 100 mdash mdash mdash mdash mdash mdashAWC minus036 095lowastlowast 046lowast minus073lowastlowast 100 mdash mdash mdash mdash mdashRAW minus036 095lowastlowast 046lowastlowast minus073lowastlowast 099lowastlowast 100 mdash mdash mdash mdashCW 025 037 092lowastlowast 024 038 038 100 mdash mdash mdashUW 014 minus078lowastlowast 004 088lowastlowast minus068lowastlowast minus068lowastlowast 014 100 mdash mdashWHC minus036 minus036 046lowast -073lowastlowast 100 100 038 minus068lowastlowast 100 mdashD 027 013 074lowastlowast 037 029 036 070lowastlowast 030 029 100Dp 012 054lowast 031 037 052lowast 052lowast 035 038 minus052lowast minus017Db 002 minus037 minus009 034 minus008 minus008 minus001 041 minus008 047lowastSand 004 minus057lowast minus048lowast 028 minus054lowast minus054lowast minus047lowast 033 minus054lowast 048lowastSilt 029 minus048lowast minus005 049lowast minus045 minus045 minus006 042 minus044 minus051lowastClay minus034 081lowastlowast 027 minus070lowast 081lowastlowast 081lowastlowast 019 minus066lowastlowast 081lowastlowast 022RF 015 minus001 039 029 minus010 minus010 033 026 minus010 007SOC minus035 085lowastlowast 039 -066lowast 081lowastlowast 081lowastlowast 031 minus061lowastlowast 081lowastlowast 025Siltclay ratio 044 004 minus006 minus008 007 007 minus020 minus035 007 minus014SOCS minus035 096lowastlowast 045 minus082lowastlowast 094lowastlowast 094lowastlowast 037 minus079lowastlowast 094lowastlowast 005lowastCorrelation is significant at the 005 level lowastlowastcorrelation is significant at the 001 level

Table 7 Principal component analysis generated based on factorloading (n 20)

Soil properties PC1 PC2 PC3HW minus036 048 023WP 098 minus001 011FC 042 084 028AWR minus079 059 007AWC 097 008 minus013RAW 097 008 minus013CW 036 081 029UW minus076 044 minus005WHC 097 008 -013D 020 086 minus023Dp minus061 minus011 019Db minus028 032 minus072Sand minus059 minus038 074Silt 011 minus057 051Clay 087 minus-001 minus024RF minus010 046 033SOC 089 minus001 008Total loadinga 1175 65 194 variance explained 4512 1893 968Cumulative variance explained 4512 1893 7373RF coarse fragments extraction method principal component analysisaSums of loadings PC1 PC2 and PC3 are the first second and thirdprincipal components

0

1

075

05

025

ndash025

ndash05

ndash075

ndash1ndash1 ndash075 ndash05 ndash025 0 025 05 075 1

AWR HW RF

D CWFC

AWC RAW WHC

Clay SOC WP

Silt

Sand

Dp

Db

UW

Variables (axes F1 and F2 6404)

F2 (1

893

)

F1 (4512)

Figure 4 Graphical representation of the first two principalcomponents of soil and moisture characteristics Extractionmethod principal component analysis (n 20)

Applied and Environmental Soil Science 9

values have already been reported in some wetland soils ofNorth Cameroon [13] Also comparatively lower availablewater contents have also been reported elsewhere such as11000mmm in Australia [38] 12500mmm in Sudan [39]and 23000mmm in India [40] e difference is oftenattributed to soil texture climate and topographic positions[9 10]

e WHC values for soils from 95 of the samplingpoints of the Bamenda Gleysols were very high(gt600mmm) and comparable with values of somewetland soil in North Cameroon [13] us Gleysolsdominated by silt and sand have low WHC values while

clay-rich ones show high WHC values [38] e highvalues of RAW observed in most of the studied soils are afunction of the soil texture and the organic mattercontents of the Gleysols

e air capacity of the studied Gleysols was highcompared to the optimum root aeration value of 1000 andthe critical value of 500 required for optimum plantperformance [40] Such high air contents indicate high freewater potential So most of the water that infiltrates intopores is retained in the profiles and induces soil imper-meability surface ponding poor aeration and floods in therainy season [41]

Mile 4 Nkwen

Below Foncha

Mulang

Ngomgham

Ntamulung

Oven-dry Moist Wet

Gravity water

Gravity water

Soil water potential (kPa log scale)

Wat

er co

nten

t (

wat

er1

00g

of d

ry so

il)

Capillary water

Plant-available waterUnavailable water

Hygroscopicwater HC WP FC

0ndash1ndash10ndash100ndash1000ndash10000ndash1000000

10

20

30

40

50

60

70

80

90

Figure 5 Mean moisture retention curve of the Gleysols from different studied sites in the Bamenda wetlands HC hygroscopic coefficientWP moisture content at permanent wilting point FC moisture content at field capacity

Table 8 Cumulative soil moisture contents (in of dry soil) used to model the water characteristic curves of the Gleysols in the Bamendawetlands

Properties HW UW UW+AWR UW+AWR+GW UW+AWR+GW+ACMile 4 Nkwen (n 3) 817 2159 2718 4148 5768Below Foncha (n 4) 1640 2186 4372 5202 8072Mulang (n 5) 1173 2367 4939 5579 7849Ngomgham (n 5) 166 2846 5691 6411 9170Ntamulung (n 3) 1422 1939 3878 4753 7384Mean (n 20) 1372 2300 4460 5220 7650HW hygroscopic water content UW unavailable water content AWR available water reserve CW capillary water content GW gravity water content ACair content n number of samples

10 Applied and Environmental Soil Science

e soil moisture characteristics increased considerablyfrom upstream at Mile 4 Nkwen to downstream atNgomgham Mulang below Foncha and Ntamulung ismight be related to transport and deposition of fine earthmaterial from upstream to downstream and to the geo-morphological configuration of the studied site or even tospecific soil characteristics like the mineralogical composi-tion of the clayey fraction Also several soil internal factorsmay be responsible for the variation in the soil moistureretention curve per site such as nonuniformity of porescontact angle difference and entrapped air in pore space[42]

e capillary water of the wetland soils was high as thiswater fraction is held to soil particles by weak surface tensionforces of soil particles and is thus available to plants Duringconditions of water stress (particularly during the dry season)capillarity plays a vital role in maintaining crop performancee soil water loss is faster at the surface than at depth causinga higher water tension at the surface than at depth [43 44] Itcauses a higher water tension at the surface than at depth andthis creates a water capillary current which moves from baseto surface and hence water rises to the surface to be availableto plants [45 46]e FC andWP are primarily influenced byirregular pore geometry and discontinuity and variations intexture and mineralogy [47ndash50]

In this study clay content of the soils correlated best withthe moisture characteristics more than any other propertye clay and SOC contents probably linked together asrevealed by their significant positive correlation favor theoccurrence of micropores and menisci that generate capil-lary forcesus they increase the specific surface area of thesoil matrix and consequently water adsorption [48] Al-though siltclay ratio displays no significant correlation withsoil moisture characteristics it negatively strongly correlateswith SOC e size and structure of clay particles were moresuitable for association with SOM molecules than the sizeand the structure of bigger soil particles [49] e clay andSOC contents are indispensable in the water and nutrientretention for plants based on their high specific surface area[50] Sand and coarse fragments contents tend to increasesoil particle density thereby increasing macroporosity and

reducing microporosity hence lowering the soil capacity toretain water [51] us low correlation coefficients betweensand and coarse fragments contents and WHC are docu-mented [52 53] meanwhile the negative correlation be-tween SOC and silt content is not in line with some results[44]

e statistical analysis of the studied soil propertiesfollowed a log-normal distribution as revealed by the co-efficient of kurtosis and skewness indicating possible an-thropogenic disturbances Under natural grasslands manysoil variables tend to conform to normal distribution due tothe homogenization effect of biotic factors [54] Followingirrigation or rainfall that saturates the soil making its watercontent higher than FC there should normally be adownward movement of water by gravity action Infiltrationis related to hydraulic conductivity that leads to decrease insoil moisture content as infiltration leads to soil water loss

42 Implications of theGleysolsCharacteristics onAgriculturalManagement Strategies In the Bamenda wetlands waterlosses often attain WP in the dry season making plant-available water contents low is condition of water stresshas been reported to cause drastic decrease in yields inwetlands [55] erefore for irrigation the ldquoplant readilyavailable waterrdquo constitutes the ideal operating range of soilmoisture for irrigation management [29 56] us irriga-tion scheduling should involve the replacement of depletedwater not higher than the FC to avoid waterlogging in thesesoils as drainage andor deep percolation is poor But sincethe soils are flooded in the rainy season it implies that theirwater content is above the FC and thus necessitating thedrainage of excess water during farming in the rainy seasone soil water characteristic curves become an indispensableto design irrigation schedules especially in the dry seasonduring moisture deficiency or to drain excess water in therainy season [57ndash59]

To achieve high yields without creating excess drainageit is necessary to know the crop readily available to becultivated After readily available water has been used plantroots cannot easily extract water and nutrients from the soil

Table 9 List of Ramsar sites in Cameroon [15]

SN Site Ramsar

identifierDesignation

date Region Geographic coordinates Altitude(m)

Surface area(km2)

1 Waza-Logone floodplain 1609 26052006 ExtremeNorth

11deg 37prime 59primeNorth14deg 37prime 01prime East 300 6000

2 Barombi-Mbo Lake 1643 810rsquo2006 South west 4deg 40prime 01primeNorth9deg 22prime 59primeEast 301ndash400 415

3 Cameroon section of theSangha River 1739 2022008 East 1deg 49prime 59primeNorth

16deg 01prime 59primeEast 350ndash700 62

4 Cameroon section of LakeChad 1903 2022010 Extreme

North12deg 46prime 01primeNorth14deg18prime 00primeEast 160ndash280 125

5 Rio Del Rey Estuary 1908 20052010 South West 4deg 37prime 01primeNorth8deg 43prime 01prime East 5 1650

6 Cameroon section of theNtem River 2067 5062012 South 2deg 22prime 44primeNorth

10deg 33prime14primeEast 400ndash526 39848

7 Ebogo Humid Zone 2028 605 2012 Centre 3deg 23prime10primeNorth11deg 29prime 20primeEast 630ndash670 3097

Applied and Environmental Soil Science 11

and this is the time to irrigate or refill pointe drier the soilis the more water it needs to return to field capacityus inirrigation FC and refill point are critical values for thecorrect use of many of the soil water monitoring

e high clay content of the Gleysols in the Bamendawetlands makes tillage and weed control in these areasdifficult due to the presence of water and sticky nature ofsoils to farm tools e high bulk density of the Gleysols isvery high (16 gmiddotcmminus3) compared to the optimum value(133 gmiddotcmminus3) for root penetration but also close to the upperlimit (175 gmiddotcmminus3) for root growth and is therefore a lim-iting factor to agriculture [60] High bulk density impliesthat the soils are not well aerated as most of the pores aresaturated with water during wet conditions

e highly significant correlation between clay and or-ganic matter contents reveals that both are linked together toform organo-mineral complexes and thus the SOC is beingprotected by soil matrix ese two soil colloids play a vital

role in the retention of water and nutrients for crop needs asrevealed by their high correlation with most of the moisturecharacteristicse high SOC implies a high cation exchangecapacity (CEC) e overall CEC of SOC and clay contentsfavors the retention and availability of nutrients to maintaincrop production in those Gleysols [60ndash62]

Particle size distribution also conditions chemical nu-trient supply [63] Most of the studied Gleysols samples haveclay plus silt content greater than 35 this indicates poornutrient assimilation by plants A correlation has also beenestablished between particle size distribution and yields [63]e (silt + sand)-to-total earth ratios of the Gleysols werevery high (gtgt35) relative to the ratio range of 15 to 35necessary for optimum yields and indicate potentially pooryields for a majority of tropical crops [63]

e SOCS of the Bamenda wetlands Gleysols is very high(gt200Mgmiddothaminus1) as such wetlands especially floodplains areoften very productive [4] Such ecosystems have the ability of

(a) (b)

(c) (d)

(e) (f )

Figure 6 Photographs of wetland ecosystems in Nkwen (Bamenda) (a) Wetland with grassed vegetation (b) water retained in furrows ofraised ridges (c d) channeling of water into farmlands for irrigation (e f ) healthy maize crops cultivated in the wetlands of Bamenda

12 Applied and Environmental Soil Science

sequestering and storing carbon through photosynthesis andorganic matter accumulation in soils and plant biomassthereby offering the opportunity for regaining lost pro-ductivity especially under agricultural systems e prop-erties of these studied soils could be similar to those of someRamsar sites in Cameroon although with some site specificfeatures Table 9 shows different Ramsar sites in Cameroon

5 Conclusion

In Bamenda City (Northwest Cameroon) population in-crease has led to considerable lawless occupation of wetlandsespecially as these areas are very fertile and support year-round agriculture Land use is often done without necessarytechnical know-how of sustainable land managementtechniques is work was focused on the determination ofmoisture characteristics of Gleysols in the Bamenda wet-lands and to establish a link between them and selected soilcharacteristics affecting crop production

e major findings revealed that the Gleysols showedvery high organic carbon contents and very high soil organiccarbon stocks implying a high level of carbon sequestrationMajor constraints of the soils to farming were clay plus siltcontents massive structure and waterlogging e moistureproperties revealed very high water-holding capacity andvery high plant-available water e particle density andcoarse fragments and sand contents correlated negativelywith the soil moisture retention characteristics and could bereducing the soilrsquos water-holding capacity e soil moisturecharacteristics curves were sigmoid-shaped and their heightsdecreased from upstream to downstream probably por-traying increase of finer material with fluvial transportdistant

e present work might have been limited in terms ofthe inadequate number of samples studied Further re-search is necessary on these wetland soils of the northwestregion of Cameroon to evaluate their potential risk ofdegradation based on a higher number of samples Alsothe results presented in this work might have been biasedbased on the fact that the tests were conducted solely inthe laboratory In the future measurements of waterstorage capacity of these soils should be done directly inthe field using more accurate methods such as electricalresistance and tensiometric and heat-diffusion methodsIrrigation schedules on this these soils should involve thereplacement of depleted water with water amounts notexceeding the FC to avoid waterlogging in these soils asdrainage andor deep percolation is poor Adapted cropslike lowland rice could also be introduced to extend thesurfaces of rice cultivation in the zone

Data Availability

Data can be made available on request

Conflicts of Interest

e authors declare no conflicts of interest

References

[1] W J Rawls T J Gish and D L Brakensiek ldquoEstimating soilwater retention from soil physical properties and character-isticsrdquoAdvances in Soil Science vol 16 pp 213ndash234 Springer-Verlag New York Inc NY USA 1991

[2] E Kellner and S Halldin ldquoWater budget and surface-layerwater storage in a Sphagnum bog in central Swedenrdquo Hy-drological Processes vol 16 no 1 pp 87ndash103 2002

[3] R M Khalid and H A K Ahmed ldquoNature of soil-watercharacteristics curves (SWCC) for soils from Anbar Gover-noraterdquo Anbar Journal of Engineering Sciences vol 3 no 1pp 61ndash80 2010

[4] e Ramsar Convention on Wetlands ldquoClimate Change andWetlands Resolution X24rdquo in Proceedings of the 10thMeeting of the Conference of the Parties to the Convention onWetlands Changwon Republic of Korea October 2008httpswwwramsarorgdocumentresolution-x24-climate-change-and-wetlands

[5] J Vopravil P Formanek and T Khel ldquoComparison of thephysical properties of soils belonging to different referencesoil groupsrdquo Soil andWater Research vol 16 pp 29ndash38 2021

[6] USDA Soil Survey Manual USDA Washington D C USA2017

[7] S R Carpenter W A Brock and P Hanson ldquoResilientmanagement comments onrdquo Ecological and Social Dynamics inSimple Models of EcosystemManagement Conservation EcologyResilience Alliance vol 3 no 2 Wisconsin USA 1999

[8] K E Saxton and W J Rawls ldquoSoil water characteristic es-timates by texture and organic matter for hydrologic solu-tionsrdquo Soil Science Society of America Journal vol 70 no 5pp 1569ndash1578 2006

[9] P A Tamfuh A H Chotangui A H Chotangui et al ldquoLandcharacteristics and agricultural suitability status along a top-osequence in Santa Bamenda Highlands Cameroonrdquo Journalof Atmospheric amp Earth Science vol 4 no 1 pp 1ndash9 2020

[10] A Kagou Dongmo C S Guedjeo P Azinwi Tamfuh et alldquoGeochemical and geotechnical characterization of soils de-veloped on volcanic rocks in the Bamenda Mountain(Cameroon volcanic line)rdquo International Journal of AdvancedGeosciences vol 6 no 2 pp 184ndash194 2018

[11] B Minasny and A E Hartemink ldquoPredicting soil propertiesin the tropicsrdquo Earth-Science Reviews vol 106 no 1-2pp 52ndash62 2011

[12] D Baros and A Albernaz ldquoPossible impacts of climate changeon wetlands and its biota in the Brazilian Amazonrdquo BrazilianJournal of Biology vol 74 no 4 pp 810ndash820 2014

[13] P Azinwi Tamfuh E Djoufac Woumfo E TemgouaA Boukong and D Bitom ldquoMoisture moisture-relatedproperties and agricultural management strategies of theBenue floodplain Vertisols in North Cameroonrdquo AfricanJournal of Agricultural Research vol 13 no 33 pp 1730ndash1746 2018

[14] IPCC (Intergovernmental Panel on Climate Change) ldquoCli-mate change 2013 the physical science basisrdquo in Contributionof Working Group I to the Fifth Assessment Report of theIntergovernmental Panel on Climate Change T F StockerD Qin G-K Plattner et al Eds Cambridge University PressCambridge UK 2013 httpwwwipccchreportar5wg1

[15] Ramsar Sites Information Service Annotated List of Wetlandsof International Importance Cameroon Ramsar Sites Infor-mation Service Gland Switzerland 2016 httpsrsisramsarorgfrris-searchlanguageframpf[0]regioncountry_fr_ss3ACameroon

Applied and Environmental Soil Science 13

22 Methodology and Analytics Twenty (20) samplingpoints representative of the Bamenda Wetlands were se-lected within five neighborhoods (Mulang NgomghamBelow Foncha and Mile 4 Nkwen) in the Bamenda mu-nicipality wetlands (Figure 2) One sample was collected perpoint at 0ndash50 cm depth (effective rooting zone for a majorityof crops cultivated in this area green beans onion lickshuckleberry tomatoes carrot etc) Disturbed and undis-turbed samples were taken for three repetitions e total

area sampled was about 30 km2 Sampling was conducted inthe dry season in November 2019 when the water level in thearea was low Soil samples collected were packed in air-tiedplastic bags and taken to the laboratory for analysis

In the laboratory the bulk density (Db) was determinedby paraffin coating method and particle density (Dp) wasmeasured by pycnometer method Porosity (p) was deducedfrom the particle and bulk densities e particle size dis-tribution was measured by Robinsonrsquos pipette method and

10deg00prime

Federal republic ofnigeria

Republic of

Chad

Cent

rafri

can

repu

blic

10deg15prime

10deg00prime

EqGuinea Gabon

E

6

3

7

S

2

5

CE

LT

SW W

NW

AD

N

EN

1

4

N

NtemSangha

Nyong

Logone

Peoplersquos rep ofCongo

10deg0

0prime05

deg00prime

10deg0

0prime05

deg00prime

10deg15prime

River

Regional boundary

Lakeocean

Figure 1 Location of the Ramsar sites in Cameroon [15] Sites are numbered from youngest to oldest based designation date (1) Waza-Logone floodplain (2) Barombi-Mbo Lake (3) Cameroon section of the Sangha River (4) Cameroon section of Lake Chad (5) Rio Del ReyEstuary (6) Cameroon section of the Ntem River (7) Ebogo Humid Zone EN Extreme North Region NW Northwest Region N NorthRegion AD Adamawa Region CE Centre Region E East Region LT Littoral Region S South Region SW Southwest Region W WestRegion

Applied and Environmental Soil Science 3

10deg00prime 10deg15prime

10deg00prime

km

0 155 310 620

10deg15prime

10deg0

0prime05

deg00prime

Federal republic ofnigeria

Republic of

Chad

Cent

rafri

can

repu

blic

EqGuinea Gabon

E

S

CE

LT

Atlanticocean

SW WNW

AD

N

EN

N

Peoplersquos repof Congo

Study site

(a)

10deg00prime 10deg10primeTo Bafoussam

To M

amfe

To K

umbo

10deg20prime

km

189450

10deg00prime 10deg10prime 10deg20prime

6deg20

prime6deg

10prime

6deg00

prime5deg

50prime

5deg40

prime

MENTCHUMBUI

BOYO

MEZAM

Tubah

Bafut

MOMO

LEBIALEM BAMBOUTOS

NG

OKE

TUN

JIA

Bali

Santa

Bamenda

Tarred road

Secondary roads

(b)

N

10deg8prime20PrimeE

6deg0prime

0PrimeN

5deg59

prime10

PrimeN

5deg58

prime20

PrimeN

5deg57

prime30

PrimeN

6deg0prime

0PrimeN

5deg59

prime10

PrimeN

5deg58

prime20

PrimeN

5deg57

prime30

PrimeN

10deg9prime10PrimeE 10deg10prime10PrimeE 10deg10prime50PrimeE

10deg8prime20PrimeE

0 04 08 16 24

10deg9prime10PrimeE 10deg10prime10PrimeE

Coordinate system WGS 84 UTM zone 32 N

10deg10prime50PrimeE

Untarred roads

Water bodles

Study area

Neighbourhood

Sample points

National road

Tarred roads

High 1787Low 1170

(c)

Figure 2 Location maps of the study area (a) location of Mezam Division in Cameroon (b) location of Bamenda in Mezam Division(c) studied site map with sampling points

4 Applied and Environmental Soil Science

SOC was analyzed by Walkley-Black method All theseanalyses were conducted according to the procedures de-scribed in [27]

e soil organic carbon stock (SOCS) was calculatedaccording to the following equation [14]

SOCS Mg middot haminus11113872 1113873 SOC content times BD times d(

times 1 minus δ2mm( 1113857 times 101113857(1)

where SOC is the organic carbon content (g kgminus1) d is thesoil layer thickness (m) δ2mm is the coarse fragments(gt2mm diameter) content () and BD is the soil bulkdensity (Mgmiddotmminus3)

e hygroscopic water content was calculated by usingthe weight loss of an air-dry sample after subjecting it to anoven temperature of 105degC for 24 hours [28] To determinethe soil water content at field capacity (FC) the soil coreswere first saturated and their soil water content at 33 kPa wasmeasured using the tension tables [29] e permanentwilting point (WP) water content at 1500 kPa suction wasmeasured on the subsample using a pressure plate apparatus[30] e capillary water (CW) was calculated as the dif-ference between the hygroscopic water and the field capacitywater content [31] e unavailable water content (UW) wasobtained as the difference between the capillary water andwater content permanent wilting point [32] Gravity water(GW) was obtained as the difference between total porosityand capillary water e air content (AC) was calculated asthe difference between the total porosity and the moisturecontent at field capacity [5] e available water reserve(AWR) was calculated as the difference between the FC andWP [33]

e available water content (AWC) was calculatedaccording to the following equation [5]

AWC Db times E times(FC minus WP)

1001113888 1113889 (2)

where FC is the moisture content at field capacity () WP isthe moisture content at permanent wilting point () E is thedepth of the soil layer (in dm) andDb is the soil bulk densityin gmiddotcmminus3

e readily available water content (RAW) was esti-mated as the product of the management allowed deficiency(approximately 23 for wetland soils) and the AWC [32]

e water-holding capacity (WHC) was calculated as theAWC multiplied by 2 according to GEPPA [34]

Before calculating the infiltration depth (in dmmiddotmminus1) ineach of the soil layers the volumetric water content wascalculated according to the following equation [35]

Vw FC middotDb

Dw

1113888 1113889 (3)

where Vw is the volumetric water content (at field capacity)in FC is the gravimetric water content at field capacity Db isthe soil bulk density and Dw is the density of water(1 gmiddotcmminus3) e infiltration depth of the soil layer was thenobtained as the product of Vw and the soil depth (in dm)[35]

23 Statistical Analyses Pearson linear correlation test andprincipal component analysis (PCA) enabled establishingthe relationship between soil characteristics

3 Results

31 Soil Characteristics e characteristics of the BamendaGleysols sampled in the five different neighborhoods arecompiled in Table 1 meanwhile results of summary sta-tistical analysis of these soil characteristics are presented inTable 2 Soil characteristics such as particle density bulkdensity total porosity and particle distribution did not varymuch amongst the different sites e SOC and SOCS werealso very high for all the studied sites but the ranges of valuesamongst the different sites differed very lightly (Table 1)eparticle density of the soils ranged between 23 and25 gmiddotcmminus3 with a mean of 236 gmiddotcmminus3 and a very lowcoefficient of variation (CV) of 286 (Table 2) About 45of the samples showed a low particle density of 23 gcm3

while the rest ranged from 24 to 25 gmiddotcmminus3e bulk densityranged from 13 to 16 gmiddotcmminus3 with a mean of 143 g cmminus3

and a very low CV e total porosity varied from 40 to4348 with a mean of 4167 and changed very little fromone locality to another (CV 30) e soils showed onlytwo grain size classes clayey to clayey loam texture (Fig-ure 3) e clayey fraction was moderately variable(CV 210) and 900 of the values fell between 30 and450 clay content e fine silt contents ranged from 80 to290 with a high CV e coarse silt contents ranged from100 to 220 with an average of 1790 and amoderate CVe fine sand fraction varied from 60 to 220 with a meanof 136 and a CV of 320 e coarse sand content fol-lowed almost the same trend as fine sand ranging from 9 to22 giving a mean of 151 and CV of 29e contents incoarse fragment varied from 3 to 25 with an average valueof 12 and a high CVe sandsilt ratio fluctuated between055 and 196 portraying a moderate coefficient of variationof 34e siltclay ratio varied between 055 and 190 witha low CV of 105 e (silt + sand)-to-total earth ratios ofthe Gleysols ranged between 5229 and 7573 e SOCfluctuated from 567 to 1945 with an average of 1366and a CV of 3032 e SOCS varied between 25163 and80493Mgmiddothaminus1 with a mean of 55330Mgmiddothaminus1 and amoderate CV

e soilmoisture characteristics are compiled in Table 3 andthe results of summary statistical analysis of moisture retentioncharacteristics are presented in Table 4 e hygroscopic watercontent varied between 720 and 2303 with amean of 1372and a CV of 360 e WP (pF31500kPa) ranged between2214 and 5886 with a mean of 448 and CV of 250emoisture content at field capacity FC (pF3 33kPa) changedbetween 4816 and 7534 showing a mean of 670 and a CVof 110 e AWR ranged between 1113 and 458 itsmean value stood at 222 and the CVwas 460eAWC ofthe studied soil varied between 21583 and 42361mmm with amean value of 3397 and a CV of 180e RAW varied from28921 to 56764mmm with a mean of 45540 and a CV of180e CWwas within the range of 2904 to 570 and themost frequent values appeared between 39 and 570 while the

Applied and Environmental Soil Science 5

Tabl

e1

Geographiccoordinatesanddetailedsoilph

ysical

characteristicsandorganicmattercontento

fBam

enda

soils

(0ndash5

0cm

depth)

S no

Long

ELatN

Altitude

Site

Particle

density

Bulk

density

Porosity

Particle

sizedistribu

tion

Coarse

fragments

Silt

sand

ratio

Silt

clay

ratio

YSO

CSO

CS

Fine

sand

Coarse

sand

Fine silt

Coarse

silt

Clay

(m)

mdashgmiddotcm

minus3

gmiddotcm

minus3

mdash

mdashmdash

Mgmiddotha

minus1

110165386

5988697

1209

Mile

4Nkw

en

24

14

4167

1219

1920

3011

123

123

6216

1030

42516

210172271

5989171

1203

24

15

4167

2122

818

319

067

067

5229

1296

58320

310175703

5988982

1208

25

15

4000

119

1721

4212

078

078

7143

1823

80493

410158177

5980301

1101

Below

Foncha

23

15

4348

1118

2021

305

128

128

6762

1621

72945

510149519

5983058

1103

23

14

4348

2212

1020

3612

087

087

5893

1864

78288

610145689

5978807

1101

24

13

4167

1710

1619

3815

092

092

6348

1621

63219

710140556

5986379

1103

24

15

4167

812

2020

4017

100

100

6838

1296

57381

810164556

5985557

1104

Mulang

24

15

4167

1219

2220

2712

193

193

6161

567

25163

910182545

5985485

1103

24

13

4167

1812

1522

3312

114

114

6250

1418

54384

1010135003

5985485

1104

23

14

4348

613

912

6021

058

058

6694

1742

71906

111013429

5979775

1104

24

16

4167

1221

1311

4312

056

056

5982

810

38149

1210159417

5975206

1102

23

14

4348

1222

919

379

060

060

6019

1418

58544

1310154991

5983772

1102

Ngomgh

am

25

15

4000

1317

2920

2912

196

196

6500

770

34650

1410144283

597592

1103

23

14

4348

1112

1120

4614

055

055

6754

1823

75211

1510139715

5990339

1102

24

15

4167

913

1916

433

071

071

7573

1134

50117

161016941

5987627

1102

23

16

4348

1113

1615

407

072

072

6961

1621

76563

1710161844

5968353

1103

24

15

4167

1222

2710

2925

162

162

5280

770

34023

1810145996

5981488

1105

Ntamulun

g23

15

4348

159

1220

449

078

078

6972

1580

69870

1910134718

5992481

1106

23

14

4348

1914

1220

3521

093

093

5537

1175

48496

2010178336

599321

1104

23

14

4348

1912

1015

443

068

068

6699

1945

80277

Yslit+

clayto

tale

arth

times100

where

totale

arth

sand

+silt+

clay

+coarse

fragments

6 Applied and Environmental Soil Science

mean value stood at 4808 and the CV was 140 e UWvaried between 244 and 2759emean value of unavailablewater of 848 was low showing a low CV at 510eWHCvaried between 43171 and 84722mmm meanwhile the meanvalues attained 67970mmm and the CV was 18 egravitational water content of the Bamendawetland soils rangedfrom 072 to 1352 with amean of 746 and a CVof 5471e infiltration depth (D) appeared between 265dmmiddotmminus1 and444dmmiddotmminus1 and the mean and CV were respectively383dmmiddotmminus1 and 12e natural air content of the soils at FCoscillated between 649 and 3186 with a mean of 2476 and aCV of 28

32 Correlation and Principal Component Analysis of the SoilCharacteristics ere was a positive correlation betweensand content and Dp and a negative correlation between DPand clay content (Table 5) Db was correlating negatively

with SOC while sand and clay contents showed a significantnegative correlation Clay and SOC contents showed asignificant positive correlation e coarse fragments con-tents correlated negatively with SOC and Db but positivelywith Db e siltclay ratio showed a significant positivecorrelation with Db Dp as well as sand silt and rockfragment contents but correlated negatively with SOC andclay contents Among the soil properties SOCS was posi-tively correlated with Db clay and silt-to-clay ratio butnegatively correlated with Dp sand silt coarse fragmentsand SOC contents No significant correlation was observedbetween the soil moisture characteristics and siltclay ratioe SOCS showed a positive correlation with FC PW CWand WHC and a negative correlation with HW AWR andUW

e analysis of linear correlation of soil moisturecharacteristics revealed that WP showed a significant pos-itive correlation with AWC and RAW and a significantnegative correlation with AWR and UW (Table 6) Also FCshowed a positive correlation with AWC RAW WHC andinfiltration depth (D) of the soil layer e AWR showed avery significant negative correlation with AWC RAW andWHC e AWC displayed a strong negative correlationwith UW while RAW displayed a strong negative corre-lation with UW e CW revealed a strong positive cor-relation with D Also UW showed a significant negativecorrelation with WHC

e PCA enabled observing a reduction of the 17original variables described to only three principal com-ponents (PC1 PC2 and PC3) explaining 7373 of the totalvariance explained (Table 7) us PC1 explained 4512 ofthe total variance and revealed significant loadings on WPAWR AWC RAW UW WHC clay and SOC while PC2expressed 1893 of the total variance and showed signif-icant loadings at FC CW and D (Figure 4) PC3 expressedsignificant loadings withDb and sand with a total variance of968 e PC1 was named the soil water retention factorbecause of a high factor loading of moisture characteristicswith soil colloids (clay and organic carbon) e PC2 wasreferred to as the available water factor because of high factorloading between available water capillary water and infil-tration depth e PC3 was denoted the soil compactionfactor as sand and bulk density affect soil porosity

Table 2 Summary statistics of the soil physical characteristics and organic matter content (n 20)

Parameters Dp Db PorosityParticle size distribution

Coarsefragments

Sandsiltratio

Siltclayratio

SOC SOCSFinesand

Coarsesand

Finesilt

Coarsesilt Clay

gmiddotcmminus3 gmiddotcmminus3 Mgmiddothaminus1

Minimum 230 130 4000 600 900 800 1000 2700 300 050 055 567 25163Maximum 250 160 4348 2200 2200 2900 2200 6000 2500 165 196 1945 80493Mean 236 145 4232 1360 1510 1570 1790 3790 1210 090 096 1366 59368SD 0067 0083 119 439 449 597 355 792 57700 031 044 414 17261CV 286 567 280 3200 2900 3850 19 21 4789 3400 105 3032 2907Skew 0549 minus0176 minus0464 0477 0400 0720 minus1197 0957 0521 099 1390 minus0450 minus052Kurtosis minus0548 minus0212 minus765 minus0575 minus129 minus008 027 171 027 056 098 minus092 minus085K-S stat 0284 0257 0287 0238 0226 0133 0269 0119 0203 0122 0210 0147 0282Dp particle density Db bulk density CV coefficient of variation SD standard deviation K-S stat KolmogorovndashSmirnov statistics

100 0

10

20

30

40

50

60

70

80

90

100

90

80

70

60

50

40

30

20

10

0100 90 80 70 60

sand

cl

ay

silt

50 40 30 20 10 0

1

2

3

4

5

67

8 9101112 13

Figure 3 Textural classes of the Bamenda Gleysols according to theUnited States Department of Agriculture textural classi-ficationmdashclassification according to the Soil Science Division Staff[6] (1) heavy clay (2) clay (3) sandy clay (4) clayey loam (5) siltyclayey (6) silty clay loam (7) sandy clay loam (8) loam (9) siltyloam (10) sandy loam (11) loamy sand (12) sand (13) loam

Applied and Environmental Soil Science 7

33 Soil Water Characteristic Curves Soil moisture char-acteristic curves enabled establishing the relationship be-tween the volumetric water content and soil matric potentialof the studied soil (Figure 5) using water retention data(Table 8) e curves revealed a sigmoid shape which slopedgently from the HW to UW steepened more from UW to

AW and became gentle from gravity water to complete poresaturation e Gleysols of Mile 4 Nkwen showed the lowestwater retention curve while those of Ngomgham displayedthe highest ones (Figure 5) e soils attained full watersaturation (HW+AWC+GW+AC) at a range of 5768 ofdry soil (Mile 4 Nkwen) to 9170 of dry soil (Ngomgham)

Table 3 Moisture characteristics of the Gleysols from the Bamenda Wetlands (n 20)

S no Site HW WP FC AWR AWC RAW CW UW GW AC WHC D() () () () (mmm) (mmm) (mmm) (mmm) (mmm) () (mmm) (dmm)

1Mile 4 Nkwen

912 366 4816 1156 28267 37878 2904 244 1263 649 56534 2652 72 4152 566 1508 33127 4439 394 788 227 1493 66253 3343 82 5606 6719 1113 4181 56025 4699 293 699 2719 83619 3974

Below Foncha

1776 4842 698 2138 37164 49799 5204 362 856 2632 74327 4125 1222 5568 7258 169 38754 5193 5436 468 1088 291 77507 46 222 4762 7328 2566 31767 42567 5108 346 941 3161 63533 3757 134 4592 6941 2349 35932 48148 4601 1009 434 2774 71863 418

Mulang

1232 2214 572 3506 21583 28921 4488 2274 321 1553 43166 3389 1088 4556 6247 1691 30824 41304 4559 603 392 208 61648 3210 743 5884 7267 1383 4076 54618 5324 64 976 2919 8152 40111 158 334 7049 3709 30391 40723 5469 2129 1302 2882 60781 44412 1221 4716 6262 1546 34147 45757 4141 325 207 1914 68294 34513

Ngomgham

1535 254 6834 4294 23436 31404 4999 2759 999 2834 46871 40414 1311 5886 7534 1648 40688 54522 5523 337 1175 3186 81376 41515 221 4228 6449 2221 33792 45281 4239 011 072 2282 67583 38116 939 5242 6726 1484 42361 56764 4887 545 539 2378 84722 42417 2302 27 728 458 24456 3277 4978 2278 811 3113 48911 4318

Ntamulung978 532 7324 2004 40257 53944 5346 1026 998 2976 80513 418

19 1567 415 6192 2042 31032 41583 4625 475 277 1844 62064 40420 1721 565 7421 1771 39157 5247 5700 050 1352 3073 78314 341

Table 4 Summary statistics of the soil moisture characteristics in the Bamenda wetlands (n 20)

Parameters HW WP FC AWR AWC RAW CW UW WHC D GW AC() () () () (mmm) (mmm) () () (mmm) (dmm) () ()

Minimum 720 2214 4816 1113 21583 28921 2904 011 43166 265 072 649Maximum 2302 5886 7534 4580 42361 56764 5700 2759 84722 4 44 1352 3186Mean 1372 4480 6700 2220 33985 45540 4809 848 67970 383 746 2476SD 487 1116 709 1016 6287 8424 665 825 12573 045 408 689CV 3600 2500 1100 4600 1800 1800 1400 9700 1800 1200 5500 2800Skew 059 minus066 minus115 127 minus048 minus048 minus121 133 minus048 minus106 minus014 minus119Kurtosis minus053 minus045 110 063 minus070 minus070 216 047 minus070 081 minus140 097K-S stat 013 013 016 020 013 013 012 025 013 022 013 020HW hygroscopic water WP permanent wilting point FC field capacity AWR available water reserve AWC available water content RAW readilyavailable water CW capillary water UW unavailable water WHC water-holding capacity D weighting depth AC air content GW gravity water CVcoefficient of variation SD standard deviation K-S stat KolmogorovndashSmirnov statistics

Table 5 Correlation amongst soil physical characteristics and soil organic carbon

Soil properties Dp Db Sand Silt Clay RF SOC Siltclay ratio SOCSDp 1 mdash mdash mdash mdash mdash mdash mdashDb 02 1 mdash mdash mdash mdash mdash mdash mdashSand 038 minus012 1 mdash mdash mdash mdash mdash mdashSilt 022 minus002 minus032 1 mdash mdash mdash mdashClay minus052lowast minus011 minus063lowastlowast minus041 1 mdash mdash mdash mdashRF 011 minus02 minus025 024 minus008 1 mdash mdash mdashSOC minus049lowast minus04 minus031 minus031 069lowastlowast minus026 1 mdash mdashSiltclay ratio 046lowast 01 017 080lowastlowast minus084lowastlowast 022 minus064lowastlowast 1 mdashSOCS minus048lowast 049lowast minus036 minus040 053lowastlowast minus032 minus065lowastlowast 098lowastlowast 100lowastCorrelation is significant at the 005 level lowastlowastcorrelation is significant at the 001 level

8 Applied and Environmental Soil Science

e height of the water characteristic curves shows a meanincreasing trend such that Ngomghamgt belowFonchagtMulanggtNtamulunggtMile 4 Nkwen

4 Discussion

41 Soil Moisture Storage Capacity of Gleysols as Affected byPhysical Properties and SOC e Gleysols of the Bamendawetlands were reddish brown wet and waterlogged with

reddish yellow and blue patches in the more waterloggedareas e surface aspect of the studied Gleysols is shown inFigure 6 ese properties are common to all wetland soils[28] e massive structure and high density of these soilscan be attributed to high clay content e high clay contentin turn made the soils stick to farm tools e sandsilt ratiois an index of weathering intensity according to Sharma et al[36] All the ratio values were greater than 045 typical ofmoderate weather e siltclay ratio of the Gleysols wasgt015 indicating that the soils are relatively young or gt020portraying a high degree of weathering potential [37] eseindices agreed with values of alluvial floodplain Gleysols[13]

e plant-available water content of the BamendaGleysols was very high according to GEPPA [34] Such high

Table 6 Pearson linear correlation coefficients amongst soil moisture characteristics (n 20)

Soil properties HW WP FC AWR AWC RAW CW UW WHC DHW 100 mdash mdash mdash mdash mdash mdash mdash mdash mdashWP minus032 100 mdash mdash mdash mdash mdash mdash mdash mdashFC 036 045 100 mdash mdash mdash mdash mdash mdash mdashAWR 059lowast minus078lowastlowast 020 100 mdash mdash mdash mdash mdash mdashAWC minus036 095lowastlowast 046lowast minus073lowastlowast 100 mdash mdash mdash mdash mdashRAW minus036 095lowastlowast 046lowastlowast minus073lowastlowast 099lowastlowast 100 mdash mdash mdash mdashCW 025 037 092lowastlowast 024 038 038 100 mdash mdash mdashUW 014 minus078lowastlowast 004 088lowastlowast minus068lowastlowast minus068lowastlowast 014 100 mdash mdashWHC minus036 minus036 046lowast -073lowastlowast 100 100 038 minus068lowastlowast 100 mdashD 027 013 074lowastlowast 037 029 036 070lowastlowast 030 029 100Dp 012 054lowast 031 037 052lowast 052lowast 035 038 minus052lowast minus017Db 002 minus037 minus009 034 minus008 minus008 minus001 041 minus008 047lowastSand 004 minus057lowast minus048lowast 028 minus054lowast minus054lowast minus047lowast 033 minus054lowast 048lowastSilt 029 minus048lowast minus005 049lowast minus045 minus045 minus006 042 minus044 minus051lowastClay minus034 081lowastlowast 027 minus070lowast 081lowastlowast 081lowastlowast 019 minus066lowastlowast 081lowastlowast 022RF 015 minus001 039 029 minus010 minus010 033 026 minus010 007SOC minus035 085lowastlowast 039 -066lowast 081lowastlowast 081lowastlowast 031 minus061lowastlowast 081lowastlowast 025Siltclay ratio 044 004 minus006 minus008 007 007 minus020 minus035 007 minus014SOCS minus035 096lowastlowast 045 minus082lowastlowast 094lowastlowast 094lowastlowast 037 minus079lowastlowast 094lowastlowast 005lowastCorrelation is significant at the 005 level lowastlowastcorrelation is significant at the 001 level

Table 7 Principal component analysis generated based on factorloading (n 20)

Soil properties PC1 PC2 PC3HW minus036 048 023WP 098 minus001 011FC 042 084 028AWR minus079 059 007AWC 097 008 minus013RAW 097 008 minus013CW 036 081 029UW minus076 044 minus005WHC 097 008 -013D 020 086 minus023Dp minus061 minus011 019Db minus028 032 minus072Sand minus059 minus038 074Silt 011 minus057 051Clay 087 minus-001 minus024RF minus010 046 033SOC 089 minus001 008Total loadinga 1175 65 194 variance explained 4512 1893 968Cumulative variance explained 4512 1893 7373RF coarse fragments extraction method principal component analysisaSums of loadings PC1 PC2 and PC3 are the first second and thirdprincipal components

0

1

075

05

025

ndash025

ndash05

ndash075

ndash1ndash1 ndash075 ndash05 ndash025 0 025 05 075 1

AWR HW RF

D CWFC

AWC RAW WHC

Clay SOC WP

Silt

Sand

Dp

Db

UW

Variables (axes F1 and F2 6404)

F2 (1

893

)

F1 (4512)

Figure 4 Graphical representation of the first two principalcomponents of soil and moisture characteristics Extractionmethod principal component analysis (n 20)

Applied and Environmental Soil Science 9

values have already been reported in some wetland soils ofNorth Cameroon [13] Also comparatively lower availablewater contents have also been reported elsewhere such as11000mmm in Australia [38] 12500mmm in Sudan [39]and 23000mmm in India [40] e difference is oftenattributed to soil texture climate and topographic positions[9 10]

e WHC values for soils from 95 of the samplingpoints of the Bamenda Gleysols were very high(gt600mmm) and comparable with values of somewetland soil in North Cameroon [13] us Gleysolsdominated by silt and sand have low WHC values while

clay-rich ones show high WHC values [38] e highvalues of RAW observed in most of the studied soils are afunction of the soil texture and the organic mattercontents of the Gleysols

e air capacity of the studied Gleysols was highcompared to the optimum root aeration value of 1000 andthe critical value of 500 required for optimum plantperformance [40] Such high air contents indicate high freewater potential So most of the water that infiltrates intopores is retained in the profiles and induces soil imper-meability surface ponding poor aeration and floods in therainy season [41]

Mile 4 Nkwen

Below Foncha

Mulang

Ngomgham

Ntamulung

Oven-dry Moist Wet

Gravity water

Gravity water

Soil water potential (kPa log scale)

Wat

er co

nten

t (

wat

er1

00g

of d

ry so

il)

Capillary water

Plant-available waterUnavailable water

Hygroscopicwater HC WP FC

0ndash1ndash10ndash100ndash1000ndash10000ndash1000000

10

20

30

40

50

60

70

80

90

Figure 5 Mean moisture retention curve of the Gleysols from different studied sites in the Bamenda wetlands HC hygroscopic coefficientWP moisture content at permanent wilting point FC moisture content at field capacity

Table 8 Cumulative soil moisture contents (in of dry soil) used to model the water characteristic curves of the Gleysols in the Bamendawetlands

Properties HW UW UW+AWR UW+AWR+GW UW+AWR+GW+ACMile 4 Nkwen (n 3) 817 2159 2718 4148 5768Below Foncha (n 4) 1640 2186 4372 5202 8072Mulang (n 5) 1173 2367 4939 5579 7849Ngomgham (n 5) 166 2846 5691 6411 9170Ntamulung (n 3) 1422 1939 3878 4753 7384Mean (n 20) 1372 2300 4460 5220 7650HW hygroscopic water content UW unavailable water content AWR available water reserve CW capillary water content GW gravity water content ACair content n number of samples

10 Applied and Environmental Soil Science

e soil moisture characteristics increased considerablyfrom upstream at Mile 4 Nkwen to downstream atNgomgham Mulang below Foncha and Ntamulung ismight be related to transport and deposition of fine earthmaterial from upstream to downstream and to the geo-morphological configuration of the studied site or even tospecific soil characteristics like the mineralogical composi-tion of the clayey fraction Also several soil internal factorsmay be responsible for the variation in the soil moistureretention curve per site such as nonuniformity of porescontact angle difference and entrapped air in pore space[42]

e capillary water of the wetland soils was high as thiswater fraction is held to soil particles by weak surface tensionforces of soil particles and is thus available to plants Duringconditions of water stress (particularly during the dry season)capillarity plays a vital role in maintaining crop performancee soil water loss is faster at the surface than at depth causinga higher water tension at the surface than at depth [43 44] Itcauses a higher water tension at the surface than at depth andthis creates a water capillary current which moves from baseto surface and hence water rises to the surface to be availableto plants [45 46]e FC andWP are primarily influenced byirregular pore geometry and discontinuity and variations intexture and mineralogy [47ndash50]

In this study clay content of the soils correlated best withthe moisture characteristics more than any other propertye clay and SOC contents probably linked together asrevealed by their significant positive correlation favor theoccurrence of micropores and menisci that generate capil-lary forcesus they increase the specific surface area of thesoil matrix and consequently water adsorption [48] Al-though siltclay ratio displays no significant correlation withsoil moisture characteristics it negatively strongly correlateswith SOC e size and structure of clay particles were moresuitable for association with SOM molecules than the sizeand the structure of bigger soil particles [49] e clay andSOC contents are indispensable in the water and nutrientretention for plants based on their high specific surface area[50] Sand and coarse fragments contents tend to increasesoil particle density thereby increasing macroporosity and

reducing microporosity hence lowering the soil capacity toretain water [51] us low correlation coefficients betweensand and coarse fragments contents and WHC are docu-mented [52 53] meanwhile the negative correlation be-tween SOC and silt content is not in line with some results[44]

e statistical analysis of the studied soil propertiesfollowed a log-normal distribution as revealed by the co-efficient of kurtosis and skewness indicating possible an-thropogenic disturbances Under natural grasslands manysoil variables tend to conform to normal distribution due tothe homogenization effect of biotic factors [54] Followingirrigation or rainfall that saturates the soil making its watercontent higher than FC there should normally be adownward movement of water by gravity action Infiltrationis related to hydraulic conductivity that leads to decrease insoil moisture content as infiltration leads to soil water loss

42 Implications of theGleysolsCharacteristics onAgriculturalManagement Strategies In the Bamenda wetlands waterlosses often attain WP in the dry season making plant-available water contents low is condition of water stresshas been reported to cause drastic decrease in yields inwetlands [55] erefore for irrigation the ldquoplant readilyavailable waterrdquo constitutes the ideal operating range of soilmoisture for irrigation management [29 56] us irriga-tion scheduling should involve the replacement of depletedwater not higher than the FC to avoid waterlogging in thesesoils as drainage andor deep percolation is poor But sincethe soils are flooded in the rainy season it implies that theirwater content is above the FC and thus necessitating thedrainage of excess water during farming in the rainy seasone soil water characteristic curves become an indispensableto design irrigation schedules especially in the dry seasonduring moisture deficiency or to drain excess water in therainy season [57ndash59]

To achieve high yields without creating excess drainageit is necessary to know the crop readily available to becultivated After readily available water has been used plantroots cannot easily extract water and nutrients from the soil

Table 9 List of Ramsar sites in Cameroon [15]

SN Site Ramsar

identifierDesignation

date Region Geographic coordinates Altitude(m)

Surface area(km2)

1 Waza-Logone floodplain 1609 26052006 ExtremeNorth

11deg 37prime 59primeNorth14deg 37prime 01prime East 300 6000

2 Barombi-Mbo Lake 1643 810rsquo2006 South west 4deg 40prime 01primeNorth9deg 22prime 59primeEast 301ndash400 415

3 Cameroon section of theSangha River 1739 2022008 East 1deg 49prime 59primeNorth

16deg 01prime 59primeEast 350ndash700 62

4 Cameroon section of LakeChad 1903 2022010 Extreme

North12deg 46prime 01primeNorth14deg18prime 00primeEast 160ndash280 125

5 Rio Del Rey Estuary 1908 20052010 South West 4deg 37prime 01primeNorth8deg 43prime 01prime East 5 1650

6 Cameroon section of theNtem River 2067 5062012 South 2deg 22prime 44primeNorth

10deg 33prime14primeEast 400ndash526 39848

7 Ebogo Humid Zone 2028 605 2012 Centre 3deg 23prime10primeNorth11deg 29prime 20primeEast 630ndash670 3097

Applied and Environmental Soil Science 11

and this is the time to irrigate or refill pointe drier the soilis the more water it needs to return to field capacityus inirrigation FC and refill point are critical values for thecorrect use of many of the soil water monitoring

e high clay content of the Gleysols in the Bamendawetlands makes tillage and weed control in these areasdifficult due to the presence of water and sticky nature ofsoils to farm tools e high bulk density of the Gleysols isvery high (16 gmiddotcmminus3) compared to the optimum value(133 gmiddotcmminus3) for root penetration but also close to the upperlimit (175 gmiddotcmminus3) for root growth and is therefore a lim-iting factor to agriculture [60] High bulk density impliesthat the soils are not well aerated as most of the pores aresaturated with water during wet conditions

e highly significant correlation between clay and or-ganic matter contents reveals that both are linked together toform organo-mineral complexes and thus the SOC is beingprotected by soil matrix ese two soil colloids play a vital

role in the retention of water and nutrients for crop needs asrevealed by their high correlation with most of the moisturecharacteristicse high SOC implies a high cation exchangecapacity (CEC) e overall CEC of SOC and clay contentsfavors the retention and availability of nutrients to maintaincrop production in those Gleysols [60ndash62]

Particle size distribution also conditions chemical nu-trient supply [63] Most of the studied Gleysols samples haveclay plus silt content greater than 35 this indicates poornutrient assimilation by plants A correlation has also beenestablished between particle size distribution and yields [63]e (silt + sand)-to-total earth ratios of the Gleysols werevery high (gtgt35) relative to the ratio range of 15 to 35necessary for optimum yields and indicate potentially pooryields for a majority of tropical crops [63]

e SOCS of the Bamenda wetlands Gleysols is very high(gt200Mgmiddothaminus1) as such wetlands especially floodplains areoften very productive [4] Such ecosystems have the ability of

(a) (b)

(c) (d)

(e) (f )

Figure 6 Photographs of wetland ecosystems in Nkwen (Bamenda) (a) Wetland with grassed vegetation (b) water retained in furrows ofraised ridges (c d) channeling of water into farmlands for irrigation (e f ) healthy maize crops cultivated in the wetlands of Bamenda

12 Applied and Environmental Soil Science

sequestering and storing carbon through photosynthesis andorganic matter accumulation in soils and plant biomassthereby offering the opportunity for regaining lost pro-ductivity especially under agricultural systems e prop-erties of these studied soils could be similar to those of someRamsar sites in Cameroon although with some site specificfeatures Table 9 shows different Ramsar sites in Cameroon

5 Conclusion

In Bamenda City (Northwest Cameroon) population in-crease has led to considerable lawless occupation of wetlandsespecially as these areas are very fertile and support year-round agriculture Land use is often done without necessarytechnical know-how of sustainable land managementtechniques is work was focused on the determination ofmoisture characteristics of Gleysols in the Bamenda wet-lands and to establish a link between them and selected soilcharacteristics affecting crop production

e major findings revealed that the Gleysols showedvery high organic carbon contents and very high soil organiccarbon stocks implying a high level of carbon sequestrationMajor constraints of the soils to farming were clay plus siltcontents massive structure and waterlogging e moistureproperties revealed very high water-holding capacity andvery high plant-available water e particle density andcoarse fragments and sand contents correlated negativelywith the soil moisture retention characteristics and could bereducing the soilrsquos water-holding capacity e soil moisturecharacteristics curves were sigmoid-shaped and their heightsdecreased from upstream to downstream probably por-traying increase of finer material with fluvial transportdistant

e present work might have been limited in terms ofthe inadequate number of samples studied Further re-search is necessary on these wetland soils of the northwestregion of Cameroon to evaluate their potential risk ofdegradation based on a higher number of samples Alsothe results presented in this work might have been biasedbased on the fact that the tests were conducted solely inthe laboratory In the future measurements of waterstorage capacity of these soils should be done directly inthe field using more accurate methods such as electricalresistance and tensiometric and heat-diffusion methodsIrrigation schedules on this these soils should involve thereplacement of depleted water with water amounts notexceeding the FC to avoid waterlogging in these soils asdrainage andor deep percolation is poor Adapted cropslike lowland rice could also be introduced to extend thesurfaces of rice cultivation in the zone

Data Availability

Data can be made available on request

Conflicts of Interest

e authors declare no conflicts of interest

References

[1] W J Rawls T J Gish and D L Brakensiek ldquoEstimating soilwater retention from soil physical properties and character-isticsrdquoAdvances in Soil Science vol 16 pp 213ndash234 Springer-Verlag New York Inc NY USA 1991

[2] E Kellner and S Halldin ldquoWater budget and surface-layerwater storage in a Sphagnum bog in central Swedenrdquo Hy-drological Processes vol 16 no 1 pp 87ndash103 2002

[3] R M Khalid and H A K Ahmed ldquoNature of soil-watercharacteristics curves (SWCC) for soils from Anbar Gover-noraterdquo Anbar Journal of Engineering Sciences vol 3 no 1pp 61ndash80 2010

[4] e Ramsar Convention on Wetlands ldquoClimate Change andWetlands Resolution X24rdquo in Proceedings of the 10thMeeting of the Conference of the Parties to the Convention onWetlands Changwon Republic of Korea October 2008httpswwwramsarorgdocumentresolution-x24-climate-change-and-wetlands

[5] J Vopravil P Formanek and T Khel ldquoComparison of thephysical properties of soils belonging to different referencesoil groupsrdquo Soil andWater Research vol 16 pp 29ndash38 2021

[6] USDA Soil Survey Manual USDA Washington D C USA2017

[7] S R Carpenter W A Brock and P Hanson ldquoResilientmanagement comments onrdquo Ecological and Social Dynamics inSimple Models of EcosystemManagement Conservation EcologyResilience Alliance vol 3 no 2 Wisconsin USA 1999

[8] K E Saxton and W J Rawls ldquoSoil water characteristic es-timates by texture and organic matter for hydrologic solu-tionsrdquo Soil Science Society of America Journal vol 70 no 5pp 1569ndash1578 2006

[9] P A Tamfuh A H Chotangui A H Chotangui et al ldquoLandcharacteristics and agricultural suitability status along a top-osequence in Santa Bamenda Highlands Cameroonrdquo Journalof Atmospheric amp Earth Science vol 4 no 1 pp 1ndash9 2020

[10] A Kagou Dongmo C S Guedjeo P Azinwi Tamfuh et alldquoGeochemical and geotechnical characterization of soils de-veloped on volcanic rocks in the Bamenda Mountain(Cameroon volcanic line)rdquo International Journal of AdvancedGeosciences vol 6 no 2 pp 184ndash194 2018

[11] B Minasny and A E Hartemink ldquoPredicting soil propertiesin the tropicsrdquo Earth-Science Reviews vol 106 no 1-2pp 52ndash62 2011

[12] D Baros and A Albernaz ldquoPossible impacts of climate changeon wetlands and its biota in the Brazilian Amazonrdquo BrazilianJournal of Biology vol 74 no 4 pp 810ndash820 2014

[13] P Azinwi Tamfuh E Djoufac Woumfo E TemgouaA Boukong and D Bitom ldquoMoisture moisture-relatedproperties and agricultural management strategies of theBenue floodplain Vertisols in North Cameroonrdquo AfricanJournal of Agricultural Research vol 13 no 33 pp 1730ndash1746 2018

[14] IPCC (Intergovernmental Panel on Climate Change) ldquoCli-mate change 2013 the physical science basisrdquo in Contributionof Working Group I to the Fifth Assessment Report of theIntergovernmental Panel on Climate Change T F StockerD Qin G-K Plattner et al Eds Cambridge University PressCambridge UK 2013 httpwwwipccchreportar5wg1

[15] Ramsar Sites Information Service Annotated List of Wetlandsof International Importance Cameroon Ramsar Sites Infor-mation Service Gland Switzerland 2016 httpsrsisramsarorgfrris-searchlanguageframpf[0]regioncountry_fr_ss3ACameroon

Applied and Environmental Soil Science 13

10deg00prime 10deg15prime

10deg00prime

km

0 155 310 620

10deg15prime

10deg0

0prime05

deg00prime

Federal republic ofnigeria

Republic of

Chad

Cent

rafri

can

repu

blic

EqGuinea Gabon

E

S

CE

LT

Atlanticocean

SW WNW

AD

N

EN

N

Peoplersquos repof Congo

Study site

(a)

10deg00prime 10deg10primeTo Bafoussam

To M

amfe

To K

umbo

10deg20prime

km

189450

10deg00prime 10deg10prime 10deg20prime

6deg20

prime6deg

10prime

6deg00

prime5deg

50prime

5deg40

prime

MENTCHUMBUI

BOYO

MEZAM

Tubah

Bafut

MOMO

LEBIALEM BAMBOUTOS

NG

OKE

TUN

JIA

Bali

Santa

Bamenda

Tarred road

Secondary roads

(b)

N

10deg8prime20PrimeE

6deg0prime

0PrimeN

5deg59

prime10

PrimeN

5deg58

prime20

PrimeN

5deg57

prime30

PrimeN

6deg0prime

0PrimeN

5deg59

prime10

PrimeN

5deg58

prime20

PrimeN

5deg57

prime30

PrimeN

10deg9prime10PrimeE 10deg10prime10PrimeE 10deg10prime50PrimeE

10deg8prime20PrimeE

0 04 08 16 24

10deg9prime10PrimeE 10deg10prime10PrimeE

Coordinate system WGS 84 UTM zone 32 N

10deg10prime50PrimeE

Untarred roads

Water bodles

Study area

Neighbourhood

Sample points

National road

Tarred roads

High 1787Low 1170

(c)

Figure 2 Location maps of the study area (a) location of Mezam Division in Cameroon (b) location of Bamenda in Mezam Division(c) studied site map with sampling points

4 Applied and Environmental Soil Science

SOC was analyzed by Walkley-Black method All theseanalyses were conducted according to the procedures de-scribed in [27]

e soil organic carbon stock (SOCS) was calculatedaccording to the following equation [14]

SOCS Mg middot haminus11113872 1113873 SOC content times BD times d(

times 1 minus δ2mm( 1113857 times 101113857(1)

where SOC is the organic carbon content (g kgminus1) d is thesoil layer thickness (m) δ2mm is the coarse fragments(gt2mm diameter) content () and BD is the soil bulkdensity (Mgmiddotmminus3)

e hygroscopic water content was calculated by usingthe weight loss of an air-dry sample after subjecting it to anoven temperature of 105degC for 24 hours [28] To determinethe soil water content at field capacity (FC) the soil coreswere first saturated and their soil water content at 33 kPa wasmeasured using the tension tables [29] e permanentwilting point (WP) water content at 1500 kPa suction wasmeasured on the subsample using a pressure plate apparatus[30] e capillary water (CW) was calculated as the dif-ference between the hygroscopic water and the field capacitywater content [31] e unavailable water content (UW) wasobtained as the difference between the capillary water andwater content permanent wilting point [32] Gravity water(GW) was obtained as the difference between total porosityand capillary water e air content (AC) was calculated asthe difference between the total porosity and the moisturecontent at field capacity [5] e available water reserve(AWR) was calculated as the difference between the FC andWP [33]

e available water content (AWC) was calculatedaccording to the following equation [5]

AWC Db times E times(FC minus WP)

1001113888 1113889 (2)

where FC is the moisture content at field capacity () WP isthe moisture content at permanent wilting point () E is thedepth of the soil layer (in dm) andDb is the soil bulk densityin gmiddotcmminus3

e readily available water content (RAW) was esti-mated as the product of the management allowed deficiency(approximately 23 for wetland soils) and the AWC [32]

e water-holding capacity (WHC) was calculated as theAWC multiplied by 2 according to GEPPA [34]

Before calculating the infiltration depth (in dmmiddotmminus1) ineach of the soil layers the volumetric water content wascalculated according to the following equation [35]

Vw FC middotDb

Dw

1113888 1113889 (3)

where Vw is the volumetric water content (at field capacity)in FC is the gravimetric water content at field capacity Db isthe soil bulk density and Dw is the density of water(1 gmiddotcmminus3) e infiltration depth of the soil layer was thenobtained as the product of Vw and the soil depth (in dm)[35]

23 Statistical Analyses Pearson linear correlation test andprincipal component analysis (PCA) enabled establishingthe relationship between soil characteristics

3 Results

31 Soil Characteristics e characteristics of the BamendaGleysols sampled in the five different neighborhoods arecompiled in Table 1 meanwhile results of summary sta-tistical analysis of these soil characteristics are presented inTable 2 Soil characteristics such as particle density bulkdensity total porosity and particle distribution did not varymuch amongst the different sites e SOC and SOCS werealso very high for all the studied sites but the ranges of valuesamongst the different sites differed very lightly (Table 1)eparticle density of the soils ranged between 23 and25 gmiddotcmminus3 with a mean of 236 gmiddotcmminus3 and a very lowcoefficient of variation (CV) of 286 (Table 2) About 45of the samples showed a low particle density of 23 gcm3

while the rest ranged from 24 to 25 gmiddotcmminus3e bulk densityranged from 13 to 16 gmiddotcmminus3 with a mean of 143 g cmminus3

and a very low CV e total porosity varied from 40 to4348 with a mean of 4167 and changed very little fromone locality to another (CV 30) e soils showed onlytwo grain size classes clayey to clayey loam texture (Fig-ure 3) e clayey fraction was moderately variable(CV 210) and 900 of the values fell between 30 and450 clay content e fine silt contents ranged from 80 to290 with a high CV e coarse silt contents ranged from100 to 220 with an average of 1790 and amoderate CVe fine sand fraction varied from 60 to 220 with a meanof 136 and a CV of 320 e coarse sand content fol-lowed almost the same trend as fine sand ranging from 9 to22 giving a mean of 151 and CV of 29e contents incoarse fragment varied from 3 to 25 with an average valueof 12 and a high CVe sandsilt ratio fluctuated between055 and 196 portraying a moderate coefficient of variationof 34e siltclay ratio varied between 055 and 190 witha low CV of 105 e (silt + sand)-to-total earth ratios ofthe Gleysols ranged between 5229 and 7573 e SOCfluctuated from 567 to 1945 with an average of 1366and a CV of 3032 e SOCS varied between 25163 and80493Mgmiddothaminus1 with a mean of 55330Mgmiddothaminus1 and amoderate CV

e soilmoisture characteristics are compiled in Table 3 andthe results of summary statistical analysis of moisture retentioncharacteristics are presented in Table 4 e hygroscopic watercontent varied between 720 and 2303 with amean of 1372and a CV of 360 e WP (pF31500kPa) ranged between2214 and 5886 with a mean of 448 and CV of 250emoisture content at field capacity FC (pF3 33kPa) changedbetween 4816 and 7534 showing a mean of 670 and a CVof 110 e AWR ranged between 1113 and 458 itsmean value stood at 222 and the CVwas 460eAWC ofthe studied soil varied between 21583 and 42361mmm with amean value of 3397 and a CV of 180e RAW varied from28921 to 56764mmm with a mean of 45540 and a CV of180e CWwas within the range of 2904 to 570 and themost frequent values appeared between 39 and 570 while the

Applied and Environmental Soil Science 5

Tabl

e1

Geographiccoordinatesanddetailedsoilph

ysical

characteristicsandorganicmattercontento

fBam

enda

soils

(0ndash5

0cm

depth)

S no

Long

ELatN

Altitude

Site

Particle

density

Bulk

density

Porosity

Particle

sizedistribu

tion

Coarse

fragments

Silt

sand

ratio

Silt

clay

ratio

YSO

CSO

CS

Fine

sand

Coarse

sand

Fine silt

Coarse

silt

Clay

(m)

mdashgmiddotcm

minus3

gmiddotcm

minus3

mdash

mdashmdash

Mgmiddotha

minus1

110165386

5988697

1209

Mile

4Nkw

en

24

14

4167

1219

1920

3011

123

123

6216

1030

42516

210172271

5989171

1203

24

15

4167

2122

818

319

067

067

5229

1296

58320

310175703

5988982

1208

25

15

4000

119

1721

4212

078

078

7143

1823

80493

410158177

5980301

1101

Below

Foncha

23

15

4348

1118

2021

305

128

128

6762

1621

72945

510149519

5983058

1103

23

14

4348

2212

1020

3612

087

087

5893

1864

78288

610145689

5978807

1101

24

13

4167

1710

1619

3815

092

092

6348

1621

63219

710140556

5986379

1103

24

15

4167

812

2020

4017

100

100

6838

1296

57381

810164556

5985557

1104

Mulang

24

15

4167

1219

2220

2712

193

193

6161

567

25163

910182545

5985485

1103

24

13

4167

1812

1522

3312

114

114

6250

1418

54384

1010135003

5985485

1104

23

14

4348

613

912

6021

058

058

6694

1742

71906

111013429

5979775

1104

24

16

4167

1221

1311

4312

056

056

5982

810

38149

1210159417

5975206

1102

23

14

4348

1222

919

379

060

060

6019

1418

58544

1310154991

5983772

1102

Ngomgh

am

25

15

4000

1317

2920

2912

196

196

6500

770

34650

1410144283

597592

1103

23

14

4348

1112

1120

4614

055

055

6754

1823

75211

1510139715

5990339

1102

24

15

4167

913

1916

433

071

071

7573

1134

50117

161016941

5987627

1102

23

16

4348

1113

1615

407

072

072

6961

1621

76563

1710161844

5968353

1103

24

15

4167

1222

2710

2925

162

162

5280

770

34023

1810145996

5981488

1105

Ntamulun

g23

15

4348

159

1220

449

078

078

6972

1580

69870

1910134718

5992481

1106

23

14

4348

1914

1220

3521

093

093

5537

1175

48496

2010178336

599321

1104

23

14

4348

1912

1015

443

068

068

6699

1945

80277

Yslit+

clayto

tale

arth

times100

where

totale

arth

sand

+silt+

clay

+coarse

fragments

6 Applied and Environmental Soil Science

mean value stood at 4808 and the CV was 140 e UWvaried between 244 and 2759emean value of unavailablewater of 848 was low showing a low CV at 510eWHCvaried between 43171 and 84722mmm meanwhile the meanvalues attained 67970mmm and the CV was 18 egravitational water content of the Bamendawetland soils rangedfrom 072 to 1352 with amean of 746 and a CVof 5471e infiltration depth (D) appeared between 265dmmiddotmminus1 and444dmmiddotmminus1 and the mean and CV were respectively383dmmiddotmminus1 and 12e natural air content of the soils at FCoscillated between 649 and 3186 with a mean of 2476 and aCV of 28

32 Correlation and Principal Component Analysis of the SoilCharacteristics ere was a positive correlation betweensand content and Dp and a negative correlation between DPand clay content (Table 5) Db was correlating negatively

with SOC while sand and clay contents showed a significantnegative correlation Clay and SOC contents showed asignificant positive correlation e coarse fragments con-tents correlated negatively with SOC and Db but positivelywith Db e siltclay ratio showed a significant positivecorrelation with Db Dp as well as sand silt and rockfragment contents but correlated negatively with SOC andclay contents Among the soil properties SOCS was posi-tively correlated with Db clay and silt-to-clay ratio butnegatively correlated with Dp sand silt coarse fragmentsand SOC contents No significant correlation was observedbetween the soil moisture characteristics and siltclay ratioe SOCS showed a positive correlation with FC PW CWand WHC and a negative correlation with HW AWR andUW

e analysis of linear correlation of soil moisturecharacteristics revealed that WP showed a significant pos-itive correlation with AWC and RAW and a significantnegative correlation with AWR and UW (Table 6) Also FCshowed a positive correlation with AWC RAW WHC andinfiltration depth (D) of the soil layer e AWR showed avery significant negative correlation with AWC RAW andWHC e AWC displayed a strong negative correlationwith UW while RAW displayed a strong negative corre-lation with UW e CW revealed a strong positive cor-relation with D Also UW showed a significant negativecorrelation with WHC

e PCA enabled observing a reduction of the 17original variables described to only three principal com-ponents (PC1 PC2 and PC3) explaining 7373 of the totalvariance explained (Table 7) us PC1 explained 4512 ofthe total variance and revealed significant loadings on WPAWR AWC RAW UW WHC clay and SOC while PC2expressed 1893 of the total variance and showed signif-icant loadings at FC CW and D (Figure 4) PC3 expressedsignificant loadings withDb and sand with a total variance of968 e PC1 was named the soil water retention factorbecause of a high factor loading of moisture characteristicswith soil colloids (clay and organic carbon) e PC2 wasreferred to as the available water factor because of high factorloading between available water capillary water and infil-tration depth e PC3 was denoted the soil compactionfactor as sand and bulk density affect soil porosity

Table 2 Summary statistics of the soil physical characteristics and organic matter content (n 20)

Parameters Dp Db PorosityParticle size distribution

Coarsefragments

Sandsiltratio

Siltclayratio

SOC SOCSFinesand

Coarsesand

Finesilt

Coarsesilt Clay

gmiddotcmminus3 gmiddotcmminus3 Mgmiddothaminus1

Minimum 230 130 4000 600 900 800 1000 2700 300 050 055 567 25163Maximum 250 160 4348 2200 2200 2900 2200 6000 2500 165 196 1945 80493Mean 236 145 4232 1360 1510 1570 1790 3790 1210 090 096 1366 59368SD 0067 0083 119 439 449 597 355 792 57700 031 044 414 17261CV 286 567 280 3200 2900 3850 19 21 4789 3400 105 3032 2907Skew 0549 minus0176 minus0464 0477 0400 0720 minus1197 0957 0521 099 1390 minus0450 minus052Kurtosis minus0548 minus0212 minus765 minus0575 minus129 minus008 027 171 027 056 098 minus092 minus085K-S stat 0284 0257 0287 0238 0226 0133 0269 0119 0203 0122 0210 0147 0282Dp particle density Db bulk density CV coefficient of variation SD standard deviation K-S stat KolmogorovndashSmirnov statistics

100 0

10

20

30

40

50

60

70

80

90

100

90

80

70

60

50

40

30

20

10

0100 90 80 70 60

sand

cl

ay

silt

50 40 30 20 10 0

1

2

3

4

5

67

8 9101112 13

Figure 3 Textural classes of the Bamenda Gleysols according to theUnited States Department of Agriculture textural classi-ficationmdashclassification according to the Soil Science Division Staff[6] (1) heavy clay (2) clay (3) sandy clay (4) clayey loam (5) siltyclayey (6) silty clay loam (7) sandy clay loam (8) loam (9) siltyloam (10) sandy loam (11) loamy sand (12) sand (13) loam

Applied and Environmental Soil Science 7

33 Soil Water Characteristic Curves Soil moisture char-acteristic curves enabled establishing the relationship be-tween the volumetric water content and soil matric potentialof the studied soil (Figure 5) using water retention data(Table 8) e curves revealed a sigmoid shape which slopedgently from the HW to UW steepened more from UW to

AW and became gentle from gravity water to complete poresaturation e Gleysols of Mile 4 Nkwen showed the lowestwater retention curve while those of Ngomgham displayedthe highest ones (Figure 5) e soils attained full watersaturation (HW+AWC+GW+AC) at a range of 5768 ofdry soil (Mile 4 Nkwen) to 9170 of dry soil (Ngomgham)

Table 3 Moisture characteristics of the Gleysols from the Bamenda Wetlands (n 20)

S no Site HW WP FC AWR AWC RAW CW UW GW AC WHC D() () () () (mmm) (mmm) (mmm) (mmm) (mmm) () (mmm) (dmm)

1Mile 4 Nkwen

912 366 4816 1156 28267 37878 2904 244 1263 649 56534 2652 72 4152 566 1508 33127 4439 394 788 227 1493 66253 3343 82 5606 6719 1113 4181 56025 4699 293 699 2719 83619 3974

Below Foncha

1776 4842 698 2138 37164 49799 5204 362 856 2632 74327 4125 1222 5568 7258 169 38754 5193 5436 468 1088 291 77507 46 222 4762 7328 2566 31767 42567 5108 346 941 3161 63533 3757 134 4592 6941 2349 35932 48148 4601 1009 434 2774 71863 418

Mulang

1232 2214 572 3506 21583 28921 4488 2274 321 1553 43166 3389 1088 4556 6247 1691 30824 41304 4559 603 392 208 61648 3210 743 5884 7267 1383 4076 54618 5324 64 976 2919 8152 40111 158 334 7049 3709 30391 40723 5469 2129 1302 2882 60781 44412 1221 4716 6262 1546 34147 45757 4141 325 207 1914 68294 34513

Ngomgham

1535 254 6834 4294 23436 31404 4999 2759 999 2834 46871 40414 1311 5886 7534 1648 40688 54522 5523 337 1175 3186 81376 41515 221 4228 6449 2221 33792 45281 4239 011 072 2282 67583 38116 939 5242 6726 1484 42361 56764 4887 545 539 2378 84722 42417 2302 27 728 458 24456 3277 4978 2278 811 3113 48911 4318

Ntamulung978 532 7324 2004 40257 53944 5346 1026 998 2976 80513 418

19 1567 415 6192 2042 31032 41583 4625 475 277 1844 62064 40420 1721 565 7421 1771 39157 5247 5700 050 1352 3073 78314 341

Table 4 Summary statistics of the soil moisture characteristics in the Bamenda wetlands (n 20)

Parameters HW WP FC AWR AWC RAW CW UW WHC D GW AC() () () () (mmm) (mmm) () () (mmm) (dmm) () ()

Minimum 720 2214 4816 1113 21583 28921 2904 011 43166 265 072 649Maximum 2302 5886 7534 4580 42361 56764 5700 2759 84722 4 44 1352 3186Mean 1372 4480 6700 2220 33985 45540 4809 848 67970 383 746 2476SD 487 1116 709 1016 6287 8424 665 825 12573 045 408 689CV 3600 2500 1100 4600 1800 1800 1400 9700 1800 1200 5500 2800Skew 059 minus066 minus115 127 minus048 minus048 minus121 133 minus048 minus106 minus014 minus119Kurtosis minus053 minus045 110 063 minus070 minus070 216 047 minus070 081 minus140 097K-S stat 013 013 016 020 013 013 012 025 013 022 013 020HW hygroscopic water WP permanent wilting point FC field capacity AWR available water reserve AWC available water content RAW readilyavailable water CW capillary water UW unavailable water WHC water-holding capacity D weighting depth AC air content GW gravity water CVcoefficient of variation SD standard deviation K-S stat KolmogorovndashSmirnov statistics

Table 5 Correlation amongst soil physical characteristics and soil organic carbon

Soil properties Dp Db Sand Silt Clay RF SOC Siltclay ratio SOCSDp 1 mdash mdash mdash mdash mdash mdash mdashDb 02 1 mdash mdash mdash mdash mdash mdash mdashSand 038 minus012 1 mdash mdash mdash mdash mdash mdashSilt 022 minus002 minus032 1 mdash mdash mdash mdashClay minus052lowast minus011 minus063lowastlowast minus041 1 mdash mdash mdash mdashRF 011 minus02 minus025 024 minus008 1 mdash mdash mdashSOC minus049lowast minus04 minus031 minus031 069lowastlowast minus026 1 mdash mdashSiltclay ratio 046lowast 01 017 080lowastlowast minus084lowastlowast 022 minus064lowastlowast 1 mdashSOCS minus048lowast 049lowast minus036 minus040 053lowastlowast minus032 minus065lowastlowast 098lowastlowast 100lowastCorrelation is significant at the 005 level lowastlowastcorrelation is significant at the 001 level

8 Applied and Environmental Soil Science

e height of the water characteristic curves shows a meanincreasing trend such that Ngomghamgt belowFonchagtMulanggtNtamulunggtMile 4 Nkwen

4 Discussion

41 Soil Moisture Storage Capacity of Gleysols as Affected byPhysical Properties and SOC e Gleysols of the Bamendawetlands were reddish brown wet and waterlogged with

reddish yellow and blue patches in the more waterloggedareas e surface aspect of the studied Gleysols is shown inFigure 6 ese properties are common to all wetland soils[28] e massive structure and high density of these soilscan be attributed to high clay content e high clay contentin turn made the soils stick to farm tools e sandsilt ratiois an index of weathering intensity according to Sharma et al[36] All the ratio values were greater than 045 typical ofmoderate weather e siltclay ratio of the Gleysols wasgt015 indicating that the soils are relatively young or gt020portraying a high degree of weathering potential [37] eseindices agreed with values of alluvial floodplain Gleysols[13]

e plant-available water content of the BamendaGleysols was very high according to GEPPA [34] Such high

Table 6 Pearson linear correlation coefficients amongst soil moisture characteristics (n 20)

Soil properties HW WP FC AWR AWC RAW CW UW WHC DHW 100 mdash mdash mdash mdash mdash mdash mdash mdash mdashWP minus032 100 mdash mdash mdash mdash mdash mdash mdash mdashFC 036 045 100 mdash mdash mdash mdash mdash mdash mdashAWR 059lowast minus078lowastlowast 020 100 mdash mdash mdash mdash mdash mdashAWC minus036 095lowastlowast 046lowast minus073lowastlowast 100 mdash mdash mdash mdash mdashRAW minus036 095lowastlowast 046lowastlowast minus073lowastlowast 099lowastlowast 100 mdash mdash mdash mdashCW 025 037 092lowastlowast 024 038 038 100 mdash mdash mdashUW 014 minus078lowastlowast 004 088lowastlowast minus068lowastlowast minus068lowastlowast 014 100 mdash mdashWHC minus036 minus036 046lowast -073lowastlowast 100 100 038 minus068lowastlowast 100 mdashD 027 013 074lowastlowast 037 029 036 070lowastlowast 030 029 100Dp 012 054lowast 031 037 052lowast 052lowast 035 038 minus052lowast minus017Db 002 minus037 minus009 034 minus008 minus008 minus001 041 minus008 047lowastSand 004 minus057lowast minus048lowast 028 minus054lowast minus054lowast minus047lowast 033 minus054lowast 048lowastSilt 029 minus048lowast minus005 049lowast minus045 minus045 minus006 042 minus044 minus051lowastClay minus034 081lowastlowast 027 minus070lowast 081lowastlowast 081lowastlowast 019 minus066lowastlowast 081lowastlowast 022RF 015 minus001 039 029 minus010 minus010 033 026 minus010 007SOC minus035 085lowastlowast 039 -066lowast 081lowastlowast 081lowastlowast 031 minus061lowastlowast 081lowastlowast 025Siltclay ratio 044 004 minus006 minus008 007 007 minus020 minus035 007 minus014SOCS minus035 096lowastlowast 045 minus082lowastlowast 094lowastlowast 094lowastlowast 037 minus079lowastlowast 094lowastlowast 005lowastCorrelation is significant at the 005 level lowastlowastcorrelation is significant at the 001 level

Table 7 Principal component analysis generated based on factorloading (n 20)

Soil properties PC1 PC2 PC3HW minus036 048 023WP 098 minus001 011FC 042 084 028AWR minus079 059 007AWC 097 008 minus013RAW 097 008 minus013CW 036 081 029UW minus076 044 minus005WHC 097 008 -013D 020 086 minus023Dp minus061 minus011 019Db minus028 032 minus072Sand minus059 minus038 074Silt 011 minus057 051Clay 087 minus-001 minus024RF minus010 046 033SOC 089 minus001 008Total loadinga 1175 65 194 variance explained 4512 1893 968Cumulative variance explained 4512 1893 7373RF coarse fragments extraction method principal component analysisaSums of loadings PC1 PC2 and PC3 are the first second and thirdprincipal components

0

1

075

05

025

ndash025

ndash05

ndash075

ndash1ndash1 ndash075 ndash05 ndash025 0 025 05 075 1

AWR HW RF

D CWFC

AWC RAW WHC

Clay SOC WP

Silt

Sand

Dp

Db

UW

Variables (axes F1 and F2 6404)

F2 (1

893

)

F1 (4512)

Figure 4 Graphical representation of the first two principalcomponents of soil and moisture characteristics Extractionmethod principal component analysis (n 20)

Applied and Environmental Soil Science 9

values have already been reported in some wetland soils ofNorth Cameroon [13] Also comparatively lower availablewater contents have also been reported elsewhere such as11000mmm in Australia [38] 12500mmm in Sudan [39]and 23000mmm in India [40] e difference is oftenattributed to soil texture climate and topographic positions[9 10]

e WHC values for soils from 95 of the samplingpoints of the Bamenda Gleysols were very high(gt600mmm) and comparable with values of somewetland soil in North Cameroon [13] us Gleysolsdominated by silt and sand have low WHC values while

clay-rich ones show high WHC values [38] e highvalues of RAW observed in most of the studied soils are afunction of the soil texture and the organic mattercontents of the Gleysols

e air capacity of the studied Gleysols was highcompared to the optimum root aeration value of 1000 andthe critical value of 500 required for optimum plantperformance [40] Such high air contents indicate high freewater potential So most of the water that infiltrates intopores is retained in the profiles and induces soil imper-meability surface ponding poor aeration and floods in therainy season [41]

Mile 4 Nkwen

Below Foncha

Mulang

Ngomgham

Ntamulung

Oven-dry Moist Wet

Gravity water

Gravity water

Soil water potential (kPa log scale)

Wat

er co

nten

t (

wat

er1

00g

of d

ry so

il)

Capillary water

Plant-available waterUnavailable water

Hygroscopicwater HC WP FC

0ndash1ndash10ndash100ndash1000ndash10000ndash1000000

10

20

30

40

50

60

70

80

90

Figure 5 Mean moisture retention curve of the Gleysols from different studied sites in the Bamenda wetlands HC hygroscopic coefficientWP moisture content at permanent wilting point FC moisture content at field capacity

Table 8 Cumulative soil moisture contents (in of dry soil) used to model the water characteristic curves of the Gleysols in the Bamendawetlands

Properties HW UW UW+AWR UW+AWR+GW UW+AWR+GW+ACMile 4 Nkwen (n 3) 817 2159 2718 4148 5768Below Foncha (n 4) 1640 2186 4372 5202 8072Mulang (n 5) 1173 2367 4939 5579 7849Ngomgham (n 5) 166 2846 5691 6411 9170Ntamulung (n 3) 1422 1939 3878 4753 7384Mean (n 20) 1372 2300 4460 5220 7650HW hygroscopic water content UW unavailable water content AWR available water reserve CW capillary water content GW gravity water content ACair content n number of samples

10 Applied and Environmental Soil Science

e soil moisture characteristics increased considerablyfrom upstream at Mile 4 Nkwen to downstream atNgomgham Mulang below Foncha and Ntamulung ismight be related to transport and deposition of fine earthmaterial from upstream to downstream and to the geo-morphological configuration of the studied site or even tospecific soil characteristics like the mineralogical composi-tion of the clayey fraction Also several soil internal factorsmay be responsible for the variation in the soil moistureretention curve per site such as nonuniformity of porescontact angle difference and entrapped air in pore space[42]

e capillary water of the wetland soils was high as thiswater fraction is held to soil particles by weak surface tensionforces of soil particles and is thus available to plants Duringconditions of water stress (particularly during the dry season)capillarity plays a vital role in maintaining crop performancee soil water loss is faster at the surface than at depth causinga higher water tension at the surface than at depth [43 44] Itcauses a higher water tension at the surface than at depth andthis creates a water capillary current which moves from baseto surface and hence water rises to the surface to be availableto plants [45 46]e FC andWP are primarily influenced byirregular pore geometry and discontinuity and variations intexture and mineralogy [47ndash50]

In this study clay content of the soils correlated best withthe moisture characteristics more than any other propertye clay and SOC contents probably linked together asrevealed by their significant positive correlation favor theoccurrence of micropores and menisci that generate capil-lary forcesus they increase the specific surface area of thesoil matrix and consequently water adsorption [48] Al-though siltclay ratio displays no significant correlation withsoil moisture characteristics it negatively strongly correlateswith SOC e size and structure of clay particles were moresuitable for association with SOM molecules than the sizeand the structure of bigger soil particles [49] e clay andSOC contents are indispensable in the water and nutrientretention for plants based on their high specific surface area[50] Sand and coarse fragments contents tend to increasesoil particle density thereby increasing macroporosity and

reducing microporosity hence lowering the soil capacity toretain water [51] us low correlation coefficients betweensand and coarse fragments contents and WHC are docu-mented [52 53] meanwhile the negative correlation be-tween SOC and silt content is not in line with some results[44]

e statistical analysis of the studied soil propertiesfollowed a log-normal distribution as revealed by the co-efficient of kurtosis and skewness indicating possible an-thropogenic disturbances Under natural grasslands manysoil variables tend to conform to normal distribution due tothe homogenization effect of biotic factors [54] Followingirrigation or rainfall that saturates the soil making its watercontent higher than FC there should normally be adownward movement of water by gravity action Infiltrationis related to hydraulic conductivity that leads to decrease insoil moisture content as infiltration leads to soil water loss

42 Implications of theGleysolsCharacteristics onAgriculturalManagement Strategies In the Bamenda wetlands waterlosses often attain WP in the dry season making plant-available water contents low is condition of water stresshas been reported to cause drastic decrease in yields inwetlands [55] erefore for irrigation the ldquoplant readilyavailable waterrdquo constitutes the ideal operating range of soilmoisture for irrigation management [29 56] us irriga-tion scheduling should involve the replacement of depletedwater not higher than the FC to avoid waterlogging in thesesoils as drainage andor deep percolation is poor But sincethe soils are flooded in the rainy season it implies that theirwater content is above the FC and thus necessitating thedrainage of excess water during farming in the rainy seasone soil water characteristic curves become an indispensableto design irrigation schedules especially in the dry seasonduring moisture deficiency or to drain excess water in therainy season [57ndash59]

To achieve high yields without creating excess drainageit is necessary to know the crop readily available to becultivated After readily available water has been used plantroots cannot easily extract water and nutrients from the soil

Table 9 List of Ramsar sites in Cameroon [15]

SN Site Ramsar

identifierDesignation

date Region Geographic coordinates Altitude(m)

Surface area(km2)

1 Waza-Logone floodplain 1609 26052006 ExtremeNorth

11deg 37prime 59primeNorth14deg 37prime 01prime East 300 6000

2 Barombi-Mbo Lake 1643 810rsquo2006 South west 4deg 40prime 01primeNorth9deg 22prime 59primeEast 301ndash400 415

3 Cameroon section of theSangha River 1739 2022008 East 1deg 49prime 59primeNorth

16deg 01prime 59primeEast 350ndash700 62

4 Cameroon section of LakeChad 1903 2022010 Extreme

North12deg 46prime 01primeNorth14deg18prime 00primeEast 160ndash280 125

5 Rio Del Rey Estuary 1908 20052010 South West 4deg 37prime 01primeNorth8deg 43prime 01prime East 5 1650

6 Cameroon section of theNtem River 2067 5062012 South 2deg 22prime 44primeNorth

10deg 33prime14primeEast 400ndash526 39848

7 Ebogo Humid Zone 2028 605 2012 Centre 3deg 23prime10primeNorth11deg 29prime 20primeEast 630ndash670 3097

Applied and Environmental Soil Science 11

and this is the time to irrigate or refill pointe drier the soilis the more water it needs to return to field capacityus inirrigation FC and refill point are critical values for thecorrect use of many of the soil water monitoring

e high clay content of the Gleysols in the Bamendawetlands makes tillage and weed control in these areasdifficult due to the presence of water and sticky nature ofsoils to farm tools e high bulk density of the Gleysols isvery high (16 gmiddotcmminus3) compared to the optimum value(133 gmiddotcmminus3) for root penetration but also close to the upperlimit (175 gmiddotcmminus3) for root growth and is therefore a lim-iting factor to agriculture [60] High bulk density impliesthat the soils are not well aerated as most of the pores aresaturated with water during wet conditions

e highly significant correlation between clay and or-ganic matter contents reveals that both are linked together toform organo-mineral complexes and thus the SOC is beingprotected by soil matrix ese two soil colloids play a vital

role in the retention of water and nutrients for crop needs asrevealed by their high correlation with most of the moisturecharacteristicse high SOC implies a high cation exchangecapacity (CEC) e overall CEC of SOC and clay contentsfavors the retention and availability of nutrients to maintaincrop production in those Gleysols [60ndash62]

Particle size distribution also conditions chemical nu-trient supply [63] Most of the studied Gleysols samples haveclay plus silt content greater than 35 this indicates poornutrient assimilation by plants A correlation has also beenestablished between particle size distribution and yields [63]e (silt + sand)-to-total earth ratios of the Gleysols werevery high (gtgt35) relative to the ratio range of 15 to 35necessary for optimum yields and indicate potentially pooryields for a majority of tropical crops [63]

e SOCS of the Bamenda wetlands Gleysols is very high(gt200Mgmiddothaminus1) as such wetlands especially floodplains areoften very productive [4] Such ecosystems have the ability of

(a) (b)

(c) (d)

(e) (f )

Figure 6 Photographs of wetland ecosystems in Nkwen (Bamenda) (a) Wetland with grassed vegetation (b) water retained in furrows ofraised ridges (c d) channeling of water into farmlands for irrigation (e f ) healthy maize crops cultivated in the wetlands of Bamenda

12 Applied and Environmental Soil Science

sequestering and storing carbon through photosynthesis andorganic matter accumulation in soils and plant biomassthereby offering the opportunity for regaining lost pro-ductivity especially under agricultural systems e prop-erties of these studied soils could be similar to those of someRamsar sites in Cameroon although with some site specificfeatures Table 9 shows different Ramsar sites in Cameroon

5 Conclusion

In Bamenda City (Northwest Cameroon) population in-crease has led to considerable lawless occupation of wetlandsespecially as these areas are very fertile and support year-round agriculture Land use is often done without necessarytechnical know-how of sustainable land managementtechniques is work was focused on the determination ofmoisture characteristics of Gleysols in the Bamenda wet-lands and to establish a link between them and selected soilcharacteristics affecting crop production

e major findings revealed that the Gleysols showedvery high organic carbon contents and very high soil organiccarbon stocks implying a high level of carbon sequestrationMajor constraints of the soils to farming were clay plus siltcontents massive structure and waterlogging e moistureproperties revealed very high water-holding capacity andvery high plant-available water e particle density andcoarse fragments and sand contents correlated negativelywith the soil moisture retention characteristics and could bereducing the soilrsquos water-holding capacity e soil moisturecharacteristics curves were sigmoid-shaped and their heightsdecreased from upstream to downstream probably por-traying increase of finer material with fluvial transportdistant

e present work might have been limited in terms ofthe inadequate number of samples studied Further re-search is necessary on these wetland soils of the northwestregion of Cameroon to evaluate their potential risk ofdegradation based on a higher number of samples Alsothe results presented in this work might have been biasedbased on the fact that the tests were conducted solely inthe laboratory In the future measurements of waterstorage capacity of these soils should be done directly inthe field using more accurate methods such as electricalresistance and tensiometric and heat-diffusion methodsIrrigation schedules on this these soils should involve thereplacement of depleted water with water amounts notexceeding the FC to avoid waterlogging in these soils asdrainage andor deep percolation is poor Adapted cropslike lowland rice could also be introduced to extend thesurfaces of rice cultivation in the zone

Data Availability

Data can be made available on request

Conflicts of Interest

e authors declare no conflicts of interest

References

[1] W J Rawls T J Gish and D L Brakensiek ldquoEstimating soilwater retention from soil physical properties and character-isticsrdquoAdvances in Soil Science vol 16 pp 213ndash234 Springer-Verlag New York Inc NY USA 1991

[2] E Kellner and S Halldin ldquoWater budget and surface-layerwater storage in a Sphagnum bog in central Swedenrdquo Hy-drological Processes vol 16 no 1 pp 87ndash103 2002

[3] R M Khalid and H A K Ahmed ldquoNature of soil-watercharacteristics curves (SWCC) for soils from Anbar Gover-noraterdquo Anbar Journal of Engineering Sciences vol 3 no 1pp 61ndash80 2010

[4] e Ramsar Convention on Wetlands ldquoClimate Change andWetlands Resolution X24rdquo in Proceedings of the 10thMeeting of the Conference of the Parties to the Convention onWetlands Changwon Republic of Korea October 2008httpswwwramsarorgdocumentresolution-x24-climate-change-and-wetlands

[5] J Vopravil P Formanek and T Khel ldquoComparison of thephysical properties of soils belonging to different referencesoil groupsrdquo Soil andWater Research vol 16 pp 29ndash38 2021

[6] USDA Soil Survey Manual USDA Washington D C USA2017

[7] S R Carpenter W A Brock and P Hanson ldquoResilientmanagement comments onrdquo Ecological and Social Dynamics inSimple Models of EcosystemManagement Conservation EcologyResilience Alliance vol 3 no 2 Wisconsin USA 1999

[8] K E Saxton and W J Rawls ldquoSoil water characteristic es-timates by texture and organic matter for hydrologic solu-tionsrdquo Soil Science Society of America Journal vol 70 no 5pp 1569ndash1578 2006

[9] P A Tamfuh A H Chotangui A H Chotangui et al ldquoLandcharacteristics and agricultural suitability status along a top-osequence in Santa Bamenda Highlands Cameroonrdquo Journalof Atmospheric amp Earth Science vol 4 no 1 pp 1ndash9 2020

[10] A Kagou Dongmo C S Guedjeo P Azinwi Tamfuh et alldquoGeochemical and geotechnical characterization of soils de-veloped on volcanic rocks in the Bamenda Mountain(Cameroon volcanic line)rdquo International Journal of AdvancedGeosciences vol 6 no 2 pp 184ndash194 2018

[11] B Minasny and A E Hartemink ldquoPredicting soil propertiesin the tropicsrdquo Earth-Science Reviews vol 106 no 1-2pp 52ndash62 2011

[12] D Baros and A Albernaz ldquoPossible impacts of climate changeon wetlands and its biota in the Brazilian Amazonrdquo BrazilianJournal of Biology vol 74 no 4 pp 810ndash820 2014

[13] P Azinwi Tamfuh E Djoufac Woumfo E TemgouaA Boukong and D Bitom ldquoMoisture moisture-relatedproperties and agricultural management strategies of theBenue floodplain Vertisols in North Cameroonrdquo AfricanJournal of Agricultural Research vol 13 no 33 pp 1730ndash1746 2018

[14] IPCC (Intergovernmental Panel on Climate Change) ldquoCli-mate change 2013 the physical science basisrdquo in Contributionof Working Group I to the Fifth Assessment Report of theIntergovernmental Panel on Climate Change T F StockerD Qin G-K Plattner et al Eds Cambridge University PressCambridge UK 2013 httpwwwipccchreportar5wg1

[15] Ramsar Sites Information Service Annotated List of Wetlandsof International Importance Cameroon Ramsar Sites Infor-mation Service Gland Switzerland 2016 httpsrsisramsarorgfrris-searchlanguageframpf[0]regioncountry_fr_ss3ACameroon

Applied and Environmental Soil Science 13

SOC was analyzed by Walkley-Black method All theseanalyses were conducted according to the procedures de-scribed in [27]

e soil organic carbon stock (SOCS) was calculatedaccording to the following equation [14]

SOCS Mg middot haminus11113872 1113873 SOC content times BD times d(

times 1 minus δ2mm( 1113857 times 101113857(1)

where SOC is the organic carbon content (g kgminus1) d is thesoil layer thickness (m) δ2mm is the coarse fragments(gt2mm diameter) content () and BD is the soil bulkdensity (Mgmiddotmminus3)

e hygroscopic water content was calculated by usingthe weight loss of an air-dry sample after subjecting it to anoven temperature of 105degC for 24 hours [28] To determinethe soil water content at field capacity (FC) the soil coreswere first saturated and their soil water content at 33 kPa wasmeasured using the tension tables [29] e permanentwilting point (WP) water content at 1500 kPa suction wasmeasured on the subsample using a pressure plate apparatus[30] e capillary water (CW) was calculated as the dif-ference between the hygroscopic water and the field capacitywater content [31] e unavailable water content (UW) wasobtained as the difference between the capillary water andwater content permanent wilting point [32] Gravity water(GW) was obtained as the difference between total porosityand capillary water e air content (AC) was calculated asthe difference between the total porosity and the moisturecontent at field capacity [5] e available water reserve(AWR) was calculated as the difference between the FC andWP [33]

e available water content (AWC) was calculatedaccording to the following equation [5]

AWC Db times E times(FC minus WP)

1001113888 1113889 (2)

where FC is the moisture content at field capacity () WP isthe moisture content at permanent wilting point () E is thedepth of the soil layer (in dm) andDb is the soil bulk densityin gmiddotcmminus3

e readily available water content (RAW) was esti-mated as the product of the management allowed deficiency(approximately 23 for wetland soils) and the AWC [32]

e water-holding capacity (WHC) was calculated as theAWC multiplied by 2 according to GEPPA [34]

Before calculating the infiltration depth (in dmmiddotmminus1) ineach of the soil layers the volumetric water content wascalculated according to the following equation [35]

Vw FC middotDb

Dw

1113888 1113889 (3)

where Vw is the volumetric water content (at field capacity)in FC is the gravimetric water content at field capacity Db isthe soil bulk density and Dw is the density of water(1 gmiddotcmminus3) e infiltration depth of the soil layer was thenobtained as the product of Vw and the soil depth (in dm)[35]

23 Statistical Analyses Pearson linear correlation test andprincipal component analysis (PCA) enabled establishingthe relationship between soil characteristics

3 Results

31 Soil Characteristics e characteristics of the BamendaGleysols sampled in the five different neighborhoods arecompiled in Table 1 meanwhile results of summary sta-tistical analysis of these soil characteristics are presented inTable 2 Soil characteristics such as particle density bulkdensity total porosity and particle distribution did not varymuch amongst the different sites e SOC and SOCS werealso very high for all the studied sites but the ranges of valuesamongst the different sites differed very lightly (Table 1)eparticle density of the soils ranged between 23 and25 gmiddotcmminus3 with a mean of 236 gmiddotcmminus3 and a very lowcoefficient of variation (CV) of 286 (Table 2) About 45of the samples showed a low particle density of 23 gcm3

while the rest ranged from 24 to 25 gmiddotcmminus3e bulk densityranged from 13 to 16 gmiddotcmminus3 with a mean of 143 g cmminus3

and a very low CV e total porosity varied from 40 to4348 with a mean of 4167 and changed very little fromone locality to another (CV 30) e soils showed onlytwo grain size classes clayey to clayey loam texture (Fig-ure 3) e clayey fraction was moderately variable(CV 210) and 900 of the values fell between 30 and450 clay content e fine silt contents ranged from 80 to290 with a high CV e coarse silt contents ranged from100 to 220 with an average of 1790 and amoderate CVe fine sand fraction varied from 60 to 220 with a meanof 136 and a CV of 320 e coarse sand content fol-lowed almost the same trend as fine sand ranging from 9 to22 giving a mean of 151 and CV of 29e contents incoarse fragment varied from 3 to 25 with an average valueof 12 and a high CVe sandsilt ratio fluctuated between055 and 196 portraying a moderate coefficient of variationof 34e siltclay ratio varied between 055 and 190 witha low CV of 105 e (silt + sand)-to-total earth ratios ofthe Gleysols ranged between 5229 and 7573 e SOCfluctuated from 567 to 1945 with an average of 1366and a CV of 3032 e SOCS varied between 25163 and80493Mgmiddothaminus1 with a mean of 55330Mgmiddothaminus1 and amoderate CV

e soilmoisture characteristics are compiled in Table 3 andthe results of summary statistical analysis of moisture retentioncharacteristics are presented in Table 4 e hygroscopic watercontent varied between 720 and 2303 with amean of 1372and a CV of 360 e WP (pF31500kPa) ranged between2214 and 5886 with a mean of 448 and CV of 250emoisture content at field capacity FC (pF3 33kPa) changedbetween 4816 and 7534 showing a mean of 670 and a CVof 110 e AWR ranged between 1113 and 458 itsmean value stood at 222 and the CVwas 460eAWC ofthe studied soil varied between 21583 and 42361mmm with amean value of 3397 and a CV of 180e RAW varied from28921 to 56764mmm with a mean of 45540 and a CV of180e CWwas within the range of 2904 to 570 and themost frequent values appeared between 39 and 570 while the

Applied and Environmental Soil Science 5

Tabl

e1

Geographiccoordinatesanddetailedsoilph

ysical

characteristicsandorganicmattercontento

fBam

enda

soils

(0ndash5

0cm

depth)

S no

Long

ELatN

Altitude

Site

Particle

density

Bulk

density

Porosity

Particle

sizedistribu

tion

Coarse

fragments

Silt

sand

ratio

Silt

clay

ratio

YSO

CSO

CS

Fine

sand

Coarse

sand

Fine silt

Coarse

silt

Clay

(m)

mdashgmiddotcm

minus3

gmiddotcm

minus3

mdash

mdashmdash

Mgmiddotha

minus1

110165386

5988697

1209

Mile

4Nkw

en

24

14

4167

1219

1920

3011

123

123

6216

1030

42516

210172271

5989171

1203

24

15

4167

2122

818

319

067

067

5229

1296

58320

310175703

5988982

1208

25

15

4000

119

1721

4212

078

078

7143

1823

80493

410158177

5980301

1101

Below

Foncha

23

15

4348

1118

2021

305

128

128

6762

1621

72945

510149519

5983058

1103

23

14

4348

2212

1020

3612

087

087

5893

1864

78288

610145689

5978807

1101

24

13

4167

1710

1619

3815

092

092

6348

1621

63219

710140556

5986379

1103

24

15

4167

812

2020

4017

100

100

6838

1296

57381

810164556

5985557

1104

Mulang

24

15

4167

1219

2220

2712

193

193

6161

567

25163

910182545

5985485

1103

24

13

4167

1812

1522

3312

114

114

6250

1418

54384

1010135003

5985485

1104

23

14

4348

613

912

6021

058

058

6694

1742

71906

111013429

5979775

1104

24

16

4167

1221

1311

4312

056

056

5982

810

38149

1210159417

5975206

1102

23

14

4348

1222

919

379

060

060

6019

1418

58544

1310154991

5983772

1102

Ngomgh

am

25

15

4000

1317

2920

2912

196

196

6500

770

34650

1410144283

597592

1103

23

14

4348

1112

1120

4614

055

055

6754

1823

75211

1510139715

5990339

1102

24

15

4167

913

1916

433

071

071

7573

1134

50117

161016941

5987627

1102

23

16

4348

1113

1615

407

072

072

6961

1621

76563

1710161844

5968353

1103

24

15

4167

1222

2710

2925

162

162

5280

770

34023

1810145996

5981488

1105

Ntamulun

g23

15

4348

159

1220

449

078

078

6972

1580

69870

1910134718

5992481

1106

23

14

4348

1914

1220

3521

093

093

5537

1175

48496

2010178336

599321

1104

23

14

4348

1912

1015

443

068

068

6699

1945

80277

Yslit+

clayto

tale

arth

times100

where

totale

arth

sand

+silt+

clay

+coarse

fragments

6 Applied and Environmental Soil Science

mean value stood at 4808 and the CV was 140 e UWvaried between 244 and 2759emean value of unavailablewater of 848 was low showing a low CV at 510eWHCvaried between 43171 and 84722mmm meanwhile the meanvalues attained 67970mmm and the CV was 18 egravitational water content of the Bamendawetland soils rangedfrom 072 to 1352 with amean of 746 and a CVof 5471e infiltration depth (D) appeared between 265dmmiddotmminus1 and444dmmiddotmminus1 and the mean and CV were respectively383dmmiddotmminus1 and 12e natural air content of the soils at FCoscillated between 649 and 3186 with a mean of 2476 and aCV of 28

32 Correlation and Principal Component Analysis of the SoilCharacteristics ere was a positive correlation betweensand content and Dp and a negative correlation between DPand clay content (Table 5) Db was correlating negatively

with SOC while sand and clay contents showed a significantnegative correlation Clay and SOC contents showed asignificant positive correlation e coarse fragments con-tents correlated negatively with SOC and Db but positivelywith Db e siltclay ratio showed a significant positivecorrelation with Db Dp as well as sand silt and rockfragment contents but correlated negatively with SOC andclay contents Among the soil properties SOCS was posi-tively correlated with Db clay and silt-to-clay ratio butnegatively correlated with Dp sand silt coarse fragmentsand SOC contents No significant correlation was observedbetween the soil moisture characteristics and siltclay ratioe SOCS showed a positive correlation with FC PW CWand WHC and a negative correlation with HW AWR andUW

e analysis of linear correlation of soil moisturecharacteristics revealed that WP showed a significant pos-itive correlation with AWC and RAW and a significantnegative correlation with AWR and UW (Table 6) Also FCshowed a positive correlation with AWC RAW WHC andinfiltration depth (D) of the soil layer e AWR showed avery significant negative correlation with AWC RAW andWHC e AWC displayed a strong negative correlationwith UW while RAW displayed a strong negative corre-lation with UW e CW revealed a strong positive cor-relation with D Also UW showed a significant negativecorrelation with WHC

e PCA enabled observing a reduction of the 17original variables described to only three principal com-ponents (PC1 PC2 and PC3) explaining 7373 of the totalvariance explained (Table 7) us PC1 explained 4512 ofthe total variance and revealed significant loadings on WPAWR AWC RAW UW WHC clay and SOC while PC2expressed 1893 of the total variance and showed signif-icant loadings at FC CW and D (Figure 4) PC3 expressedsignificant loadings withDb and sand with a total variance of968 e PC1 was named the soil water retention factorbecause of a high factor loading of moisture characteristicswith soil colloids (clay and organic carbon) e PC2 wasreferred to as the available water factor because of high factorloading between available water capillary water and infil-tration depth e PC3 was denoted the soil compactionfactor as sand and bulk density affect soil porosity

Table 2 Summary statistics of the soil physical characteristics and organic matter content (n 20)

Parameters Dp Db PorosityParticle size distribution

Coarsefragments

Sandsiltratio

Siltclayratio

SOC SOCSFinesand

Coarsesand

Finesilt

Coarsesilt Clay

gmiddotcmminus3 gmiddotcmminus3 Mgmiddothaminus1

Minimum 230 130 4000 600 900 800 1000 2700 300 050 055 567 25163Maximum 250 160 4348 2200 2200 2900 2200 6000 2500 165 196 1945 80493Mean 236 145 4232 1360 1510 1570 1790 3790 1210 090 096 1366 59368SD 0067 0083 119 439 449 597 355 792 57700 031 044 414 17261CV 286 567 280 3200 2900 3850 19 21 4789 3400 105 3032 2907Skew 0549 minus0176 minus0464 0477 0400 0720 minus1197 0957 0521 099 1390 minus0450 minus052Kurtosis minus0548 minus0212 minus765 minus0575 minus129 minus008 027 171 027 056 098 minus092 minus085K-S stat 0284 0257 0287 0238 0226 0133 0269 0119 0203 0122 0210 0147 0282Dp particle density Db bulk density CV coefficient of variation SD standard deviation K-S stat KolmogorovndashSmirnov statistics

100 0

10

20

30

40

50

60

70

80

90

100

90

80

70

60

50

40

30

20

10

0100 90 80 70 60

sand

cl

ay

silt

50 40 30 20 10 0

1

2

3

4

5

67

8 9101112 13

Figure 3 Textural classes of the Bamenda Gleysols according to theUnited States Department of Agriculture textural classi-ficationmdashclassification according to the Soil Science Division Staff[6] (1) heavy clay (2) clay (3) sandy clay (4) clayey loam (5) siltyclayey (6) silty clay loam (7) sandy clay loam (8) loam (9) siltyloam (10) sandy loam (11) loamy sand (12) sand (13) loam

Applied and Environmental Soil Science 7

33 Soil Water Characteristic Curves Soil moisture char-acteristic curves enabled establishing the relationship be-tween the volumetric water content and soil matric potentialof the studied soil (Figure 5) using water retention data(Table 8) e curves revealed a sigmoid shape which slopedgently from the HW to UW steepened more from UW to

AW and became gentle from gravity water to complete poresaturation e Gleysols of Mile 4 Nkwen showed the lowestwater retention curve while those of Ngomgham displayedthe highest ones (Figure 5) e soils attained full watersaturation (HW+AWC+GW+AC) at a range of 5768 ofdry soil (Mile 4 Nkwen) to 9170 of dry soil (Ngomgham)

Table 3 Moisture characteristics of the Gleysols from the Bamenda Wetlands (n 20)

S no Site HW WP FC AWR AWC RAW CW UW GW AC WHC D() () () () (mmm) (mmm) (mmm) (mmm) (mmm) () (mmm) (dmm)

1Mile 4 Nkwen

912 366 4816 1156 28267 37878 2904 244 1263 649 56534 2652 72 4152 566 1508 33127 4439 394 788 227 1493 66253 3343 82 5606 6719 1113 4181 56025 4699 293 699 2719 83619 3974

Below Foncha

1776 4842 698 2138 37164 49799 5204 362 856 2632 74327 4125 1222 5568 7258 169 38754 5193 5436 468 1088 291 77507 46 222 4762 7328 2566 31767 42567 5108 346 941 3161 63533 3757 134 4592 6941 2349 35932 48148 4601 1009 434 2774 71863 418

Mulang

1232 2214 572 3506 21583 28921 4488 2274 321 1553 43166 3389 1088 4556 6247 1691 30824 41304 4559 603 392 208 61648 3210 743 5884 7267 1383 4076 54618 5324 64 976 2919 8152 40111 158 334 7049 3709 30391 40723 5469 2129 1302 2882 60781 44412 1221 4716 6262 1546 34147 45757 4141 325 207 1914 68294 34513

Ngomgham

1535 254 6834 4294 23436 31404 4999 2759 999 2834 46871 40414 1311 5886 7534 1648 40688 54522 5523 337 1175 3186 81376 41515 221 4228 6449 2221 33792 45281 4239 011 072 2282 67583 38116 939 5242 6726 1484 42361 56764 4887 545 539 2378 84722 42417 2302 27 728 458 24456 3277 4978 2278 811 3113 48911 4318

Ntamulung978 532 7324 2004 40257 53944 5346 1026 998 2976 80513 418

19 1567 415 6192 2042 31032 41583 4625 475 277 1844 62064 40420 1721 565 7421 1771 39157 5247 5700 050 1352 3073 78314 341

Table 4 Summary statistics of the soil moisture characteristics in the Bamenda wetlands (n 20)

Parameters HW WP FC AWR AWC RAW CW UW WHC D GW AC() () () () (mmm) (mmm) () () (mmm) (dmm) () ()

Minimum 720 2214 4816 1113 21583 28921 2904 011 43166 265 072 649Maximum 2302 5886 7534 4580 42361 56764 5700 2759 84722 4 44 1352 3186Mean 1372 4480 6700 2220 33985 45540 4809 848 67970 383 746 2476SD 487 1116 709 1016 6287 8424 665 825 12573 045 408 689CV 3600 2500 1100 4600 1800 1800 1400 9700 1800 1200 5500 2800Skew 059 minus066 minus115 127 minus048 minus048 minus121 133 minus048 minus106 minus014 minus119Kurtosis minus053 minus045 110 063 minus070 minus070 216 047 minus070 081 minus140 097K-S stat 013 013 016 020 013 013 012 025 013 022 013 020HW hygroscopic water WP permanent wilting point FC field capacity AWR available water reserve AWC available water content RAW readilyavailable water CW capillary water UW unavailable water WHC water-holding capacity D weighting depth AC air content GW gravity water CVcoefficient of variation SD standard deviation K-S stat KolmogorovndashSmirnov statistics

Table 5 Correlation amongst soil physical characteristics and soil organic carbon

Soil properties Dp Db Sand Silt Clay RF SOC Siltclay ratio SOCSDp 1 mdash mdash mdash mdash mdash mdash mdashDb 02 1 mdash mdash mdash mdash mdash mdash mdashSand 038 minus012 1 mdash mdash mdash mdash mdash mdashSilt 022 minus002 minus032 1 mdash mdash mdash mdashClay minus052lowast minus011 minus063lowastlowast minus041 1 mdash mdash mdash mdashRF 011 minus02 minus025 024 minus008 1 mdash mdash mdashSOC minus049lowast minus04 minus031 minus031 069lowastlowast minus026 1 mdash mdashSiltclay ratio 046lowast 01 017 080lowastlowast minus084lowastlowast 022 minus064lowastlowast 1 mdashSOCS minus048lowast 049lowast minus036 minus040 053lowastlowast minus032 minus065lowastlowast 098lowastlowast 100lowastCorrelation is significant at the 005 level lowastlowastcorrelation is significant at the 001 level

8 Applied and Environmental Soil Science

e height of the water characteristic curves shows a meanincreasing trend such that Ngomghamgt belowFonchagtMulanggtNtamulunggtMile 4 Nkwen

4 Discussion

41 Soil Moisture Storage Capacity of Gleysols as Affected byPhysical Properties and SOC e Gleysols of the Bamendawetlands were reddish brown wet and waterlogged with

reddish yellow and blue patches in the more waterloggedareas e surface aspect of the studied Gleysols is shown inFigure 6 ese properties are common to all wetland soils[28] e massive structure and high density of these soilscan be attributed to high clay content e high clay contentin turn made the soils stick to farm tools e sandsilt ratiois an index of weathering intensity according to Sharma et al[36] All the ratio values were greater than 045 typical ofmoderate weather e siltclay ratio of the Gleysols wasgt015 indicating that the soils are relatively young or gt020portraying a high degree of weathering potential [37] eseindices agreed with values of alluvial floodplain Gleysols[13]

e plant-available water content of the BamendaGleysols was very high according to GEPPA [34] Such high

Table 6 Pearson linear correlation coefficients amongst soil moisture characteristics (n 20)

Soil properties HW WP FC AWR AWC RAW CW UW WHC DHW 100 mdash mdash mdash mdash mdash mdash mdash mdash mdashWP minus032 100 mdash mdash mdash mdash mdash mdash mdash mdashFC 036 045 100 mdash mdash mdash mdash mdash mdash mdashAWR 059lowast minus078lowastlowast 020 100 mdash mdash mdash mdash mdash mdashAWC minus036 095lowastlowast 046lowast minus073lowastlowast 100 mdash mdash mdash mdash mdashRAW minus036 095lowastlowast 046lowastlowast minus073lowastlowast 099lowastlowast 100 mdash mdash mdash mdashCW 025 037 092lowastlowast 024 038 038 100 mdash mdash mdashUW 014 minus078lowastlowast 004 088lowastlowast minus068lowastlowast minus068lowastlowast 014 100 mdash mdashWHC minus036 minus036 046lowast -073lowastlowast 100 100 038 minus068lowastlowast 100 mdashD 027 013 074lowastlowast 037 029 036 070lowastlowast 030 029 100Dp 012 054lowast 031 037 052lowast 052lowast 035 038 minus052lowast minus017Db 002 minus037 minus009 034 minus008 minus008 minus001 041 minus008 047lowastSand 004 minus057lowast minus048lowast 028 minus054lowast minus054lowast minus047lowast 033 minus054lowast 048lowastSilt 029 minus048lowast minus005 049lowast minus045 minus045 minus006 042 minus044 minus051lowastClay minus034 081lowastlowast 027 minus070lowast 081lowastlowast 081lowastlowast 019 minus066lowastlowast 081lowastlowast 022RF 015 minus001 039 029 minus010 minus010 033 026 minus010 007SOC minus035 085lowastlowast 039 -066lowast 081lowastlowast 081lowastlowast 031 minus061lowastlowast 081lowastlowast 025Siltclay ratio 044 004 minus006 minus008 007 007 minus020 minus035 007 minus014SOCS minus035 096lowastlowast 045 minus082lowastlowast 094lowastlowast 094lowastlowast 037 minus079lowastlowast 094lowastlowast 005lowastCorrelation is significant at the 005 level lowastlowastcorrelation is significant at the 001 level

Table 7 Principal component analysis generated based on factorloading (n 20)

Soil properties PC1 PC2 PC3HW minus036 048 023WP 098 minus001 011FC 042 084 028AWR minus079 059 007AWC 097 008 minus013RAW 097 008 minus013CW 036 081 029UW minus076 044 minus005WHC 097 008 -013D 020 086 minus023Dp minus061 minus011 019Db minus028 032 minus072Sand minus059 minus038 074Silt 011 minus057 051Clay 087 minus-001 minus024RF minus010 046 033SOC 089 minus001 008Total loadinga 1175 65 194 variance explained 4512 1893 968Cumulative variance explained 4512 1893 7373RF coarse fragments extraction method principal component analysisaSums of loadings PC1 PC2 and PC3 are the first second and thirdprincipal components

0

1

075

05

025

ndash025

ndash05

ndash075

ndash1ndash1 ndash075 ndash05 ndash025 0 025 05 075 1

AWR HW RF

D CWFC

AWC RAW WHC

Clay SOC WP

Silt

Sand

Dp

Db

UW

Variables (axes F1 and F2 6404)

F2 (1

893

)

F1 (4512)

Figure 4 Graphical representation of the first two principalcomponents of soil and moisture characteristics Extractionmethod principal component analysis (n 20)

Applied and Environmental Soil Science 9

values have already been reported in some wetland soils ofNorth Cameroon [13] Also comparatively lower availablewater contents have also been reported elsewhere such as11000mmm in Australia [38] 12500mmm in Sudan [39]and 23000mmm in India [40] e difference is oftenattributed to soil texture climate and topographic positions[9 10]

e WHC values for soils from 95 of the samplingpoints of the Bamenda Gleysols were very high(gt600mmm) and comparable with values of somewetland soil in North Cameroon [13] us Gleysolsdominated by silt and sand have low WHC values while

clay-rich ones show high WHC values [38] e highvalues of RAW observed in most of the studied soils are afunction of the soil texture and the organic mattercontents of the Gleysols

e air capacity of the studied Gleysols was highcompared to the optimum root aeration value of 1000 andthe critical value of 500 required for optimum plantperformance [40] Such high air contents indicate high freewater potential So most of the water that infiltrates intopores is retained in the profiles and induces soil imper-meability surface ponding poor aeration and floods in therainy season [41]

Mile 4 Nkwen

Below Foncha

Mulang

Ngomgham

Ntamulung

Oven-dry Moist Wet

Gravity water

Gravity water

Soil water potential (kPa log scale)

Wat

er co

nten

t (

wat

er1

00g

of d

ry so

il)

Capillary water

Plant-available waterUnavailable water

Hygroscopicwater HC WP FC

0ndash1ndash10ndash100ndash1000ndash10000ndash1000000

10

20

30

40

50

60

70

80

90

Figure 5 Mean moisture retention curve of the Gleysols from different studied sites in the Bamenda wetlands HC hygroscopic coefficientWP moisture content at permanent wilting point FC moisture content at field capacity

Table 8 Cumulative soil moisture contents (in of dry soil) used to model the water characteristic curves of the Gleysols in the Bamendawetlands

Properties HW UW UW+AWR UW+AWR+GW UW+AWR+GW+ACMile 4 Nkwen (n 3) 817 2159 2718 4148 5768Below Foncha (n 4) 1640 2186 4372 5202 8072Mulang (n 5) 1173 2367 4939 5579 7849Ngomgham (n 5) 166 2846 5691 6411 9170Ntamulung (n 3) 1422 1939 3878 4753 7384Mean (n 20) 1372 2300 4460 5220 7650HW hygroscopic water content UW unavailable water content AWR available water reserve CW capillary water content GW gravity water content ACair content n number of samples

10 Applied and Environmental Soil Science

e soil moisture characteristics increased considerablyfrom upstream at Mile 4 Nkwen to downstream atNgomgham Mulang below Foncha and Ntamulung ismight be related to transport and deposition of fine earthmaterial from upstream to downstream and to the geo-morphological configuration of the studied site or even tospecific soil characteristics like the mineralogical composi-tion of the clayey fraction Also several soil internal factorsmay be responsible for the variation in the soil moistureretention curve per site such as nonuniformity of porescontact angle difference and entrapped air in pore space[42]

e capillary water of the wetland soils was high as thiswater fraction is held to soil particles by weak surface tensionforces of soil particles and is thus available to plants Duringconditions of water stress (particularly during the dry season)capillarity plays a vital role in maintaining crop performancee soil water loss is faster at the surface than at depth causinga higher water tension at the surface than at depth [43 44] Itcauses a higher water tension at the surface than at depth andthis creates a water capillary current which moves from baseto surface and hence water rises to the surface to be availableto plants [45 46]e FC andWP are primarily influenced byirregular pore geometry and discontinuity and variations intexture and mineralogy [47ndash50]

In this study clay content of the soils correlated best withthe moisture characteristics more than any other propertye clay and SOC contents probably linked together asrevealed by their significant positive correlation favor theoccurrence of micropores and menisci that generate capil-lary forcesus they increase the specific surface area of thesoil matrix and consequently water adsorption [48] Al-though siltclay ratio displays no significant correlation withsoil moisture characteristics it negatively strongly correlateswith SOC e size and structure of clay particles were moresuitable for association with SOM molecules than the sizeand the structure of bigger soil particles [49] e clay andSOC contents are indispensable in the water and nutrientretention for plants based on their high specific surface area[50] Sand and coarse fragments contents tend to increasesoil particle density thereby increasing macroporosity and

reducing microporosity hence lowering the soil capacity toretain water [51] us low correlation coefficients betweensand and coarse fragments contents and WHC are docu-mented [52 53] meanwhile the negative correlation be-tween SOC and silt content is not in line with some results[44]

e statistical analysis of the studied soil propertiesfollowed a log-normal distribution as revealed by the co-efficient of kurtosis and skewness indicating possible an-thropogenic disturbances Under natural grasslands manysoil variables tend to conform to normal distribution due tothe homogenization effect of biotic factors [54] Followingirrigation or rainfall that saturates the soil making its watercontent higher than FC there should normally be adownward movement of water by gravity action Infiltrationis related to hydraulic conductivity that leads to decrease insoil moisture content as infiltration leads to soil water loss

42 Implications of theGleysolsCharacteristics onAgriculturalManagement Strategies In the Bamenda wetlands waterlosses often attain WP in the dry season making plant-available water contents low is condition of water stresshas been reported to cause drastic decrease in yields inwetlands [55] erefore for irrigation the ldquoplant readilyavailable waterrdquo constitutes the ideal operating range of soilmoisture for irrigation management [29 56] us irriga-tion scheduling should involve the replacement of depletedwater not higher than the FC to avoid waterlogging in thesesoils as drainage andor deep percolation is poor But sincethe soils are flooded in the rainy season it implies that theirwater content is above the FC and thus necessitating thedrainage of excess water during farming in the rainy seasone soil water characteristic curves become an indispensableto design irrigation schedules especially in the dry seasonduring moisture deficiency or to drain excess water in therainy season [57ndash59]

To achieve high yields without creating excess drainageit is necessary to know the crop readily available to becultivated After readily available water has been used plantroots cannot easily extract water and nutrients from the soil

Table 9 List of Ramsar sites in Cameroon [15]

SN Site Ramsar

identifierDesignation

date Region Geographic coordinates Altitude(m)

Surface area(km2)

1 Waza-Logone floodplain 1609 26052006 ExtremeNorth

11deg 37prime 59primeNorth14deg 37prime 01prime East 300 6000

2 Barombi-Mbo Lake 1643 810rsquo2006 South west 4deg 40prime 01primeNorth9deg 22prime 59primeEast 301ndash400 415

3 Cameroon section of theSangha River 1739 2022008 East 1deg 49prime 59primeNorth

16deg 01prime 59primeEast 350ndash700 62

4 Cameroon section of LakeChad 1903 2022010 Extreme

North12deg 46prime 01primeNorth14deg18prime 00primeEast 160ndash280 125

5 Rio Del Rey Estuary 1908 20052010 South West 4deg 37prime 01primeNorth8deg 43prime 01prime East 5 1650

6 Cameroon section of theNtem River 2067 5062012 South 2deg 22prime 44primeNorth

10deg 33prime14primeEast 400ndash526 39848

7 Ebogo Humid Zone 2028 605 2012 Centre 3deg 23prime10primeNorth11deg 29prime 20primeEast 630ndash670 3097

Applied and Environmental Soil Science 11

and this is the time to irrigate or refill pointe drier the soilis the more water it needs to return to field capacityus inirrigation FC and refill point are critical values for thecorrect use of many of the soil water monitoring

e high clay content of the Gleysols in the Bamendawetlands makes tillage and weed control in these areasdifficult due to the presence of water and sticky nature ofsoils to farm tools e high bulk density of the Gleysols isvery high (16 gmiddotcmminus3) compared to the optimum value(133 gmiddotcmminus3) for root penetration but also close to the upperlimit (175 gmiddotcmminus3) for root growth and is therefore a lim-iting factor to agriculture [60] High bulk density impliesthat the soils are not well aerated as most of the pores aresaturated with water during wet conditions

e highly significant correlation between clay and or-ganic matter contents reveals that both are linked together toform organo-mineral complexes and thus the SOC is beingprotected by soil matrix ese two soil colloids play a vital

role in the retention of water and nutrients for crop needs asrevealed by their high correlation with most of the moisturecharacteristicse high SOC implies a high cation exchangecapacity (CEC) e overall CEC of SOC and clay contentsfavors the retention and availability of nutrients to maintaincrop production in those Gleysols [60ndash62]

Particle size distribution also conditions chemical nu-trient supply [63] Most of the studied Gleysols samples haveclay plus silt content greater than 35 this indicates poornutrient assimilation by plants A correlation has also beenestablished between particle size distribution and yields [63]e (silt + sand)-to-total earth ratios of the Gleysols werevery high (gtgt35) relative to the ratio range of 15 to 35necessary for optimum yields and indicate potentially pooryields for a majority of tropical crops [63]

e SOCS of the Bamenda wetlands Gleysols is very high(gt200Mgmiddothaminus1) as such wetlands especially floodplains areoften very productive [4] Such ecosystems have the ability of

(a) (b)

(c) (d)

(e) (f )

Figure 6 Photographs of wetland ecosystems in Nkwen (Bamenda) (a) Wetland with grassed vegetation (b) water retained in furrows ofraised ridges (c d) channeling of water into farmlands for irrigation (e f ) healthy maize crops cultivated in the wetlands of Bamenda

12 Applied and Environmental Soil Science

sequestering and storing carbon through photosynthesis andorganic matter accumulation in soils and plant biomassthereby offering the opportunity for regaining lost pro-ductivity especially under agricultural systems e prop-erties of these studied soils could be similar to those of someRamsar sites in Cameroon although with some site specificfeatures Table 9 shows different Ramsar sites in Cameroon

5 Conclusion

In Bamenda City (Northwest Cameroon) population in-crease has led to considerable lawless occupation of wetlandsespecially as these areas are very fertile and support year-round agriculture Land use is often done without necessarytechnical know-how of sustainable land managementtechniques is work was focused on the determination ofmoisture characteristics of Gleysols in the Bamenda wet-lands and to establish a link between them and selected soilcharacteristics affecting crop production

e major findings revealed that the Gleysols showedvery high organic carbon contents and very high soil organiccarbon stocks implying a high level of carbon sequestrationMajor constraints of the soils to farming were clay plus siltcontents massive structure and waterlogging e moistureproperties revealed very high water-holding capacity andvery high plant-available water e particle density andcoarse fragments and sand contents correlated negativelywith the soil moisture retention characteristics and could bereducing the soilrsquos water-holding capacity e soil moisturecharacteristics curves were sigmoid-shaped and their heightsdecreased from upstream to downstream probably por-traying increase of finer material with fluvial transportdistant

e present work might have been limited in terms ofthe inadequate number of samples studied Further re-search is necessary on these wetland soils of the northwestregion of Cameroon to evaluate their potential risk ofdegradation based on a higher number of samples Alsothe results presented in this work might have been biasedbased on the fact that the tests were conducted solely inthe laboratory In the future measurements of waterstorage capacity of these soils should be done directly inthe field using more accurate methods such as electricalresistance and tensiometric and heat-diffusion methodsIrrigation schedules on this these soils should involve thereplacement of depleted water with water amounts notexceeding the FC to avoid waterlogging in these soils asdrainage andor deep percolation is poor Adapted cropslike lowland rice could also be introduced to extend thesurfaces of rice cultivation in the zone

Data Availability

Data can be made available on request

Conflicts of Interest

e authors declare no conflicts of interest

References

[1] W J Rawls T J Gish and D L Brakensiek ldquoEstimating soilwater retention from soil physical properties and character-isticsrdquoAdvances in Soil Science vol 16 pp 213ndash234 Springer-Verlag New York Inc NY USA 1991

[2] E Kellner and S Halldin ldquoWater budget and surface-layerwater storage in a Sphagnum bog in central Swedenrdquo Hy-drological Processes vol 16 no 1 pp 87ndash103 2002

[3] R M Khalid and H A K Ahmed ldquoNature of soil-watercharacteristics curves (SWCC) for soils from Anbar Gover-noraterdquo Anbar Journal of Engineering Sciences vol 3 no 1pp 61ndash80 2010

[4] e Ramsar Convention on Wetlands ldquoClimate Change andWetlands Resolution X24rdquo in Proceedings of the 10thMeeting of the Conference of the Parties to the Convention onWetlands Changwon Republic of Korea October 2008httpswwwramsarorgdocumentresolution-x24-climate-change-and-wetlands

[5] J Vopravil P Formanek and T Khel ldquoComparison of thephysical properties of soils belonging to different referencesoil groupsrdquo Soil andWater Research vol 16 pp 29ndash38 2021

[6] USDA Soil Survey Manual USDA Washington D C USA2017

[7] S R Carpenter W A Brock and P Hanson ldquoResilientmanagement comments onrdquo Ecological and Social Dynamics inSimple Models of EcosystemManagement Conservation EcologyResilience Alliance vol 3 no 2 Wisconsin USA 1999

[8] K E Saxton and W J Rawls ldquoSoil water characteristic es-timates by texture and organic matter for hydrologic solu-tionsrdquo Soil Science Society of America Journal vol 70 no 5pp 1569ndash1578 2006

[9] P A Tamfuh A H Chotangui A H Chotangui et al ldquoLandcharacteristics and agricultural suitability status along a top-osequence in Santa Bamenda Highlands Cameroonrdquo Journalof Atmospheric amp Earth Science vol 4 no 1 pp 1ndash9 2020

[10] A Kagou Dongmo C S Guedjeo P Azinwi Tamfuh et alldquoGeochemical and geotechnical characterization of soils de-veloped on volcanic rocks in the Bamenda Mountain(Cameroon volcanic line)rdquo International Journal of AdvancedGeosciences vol 6 no 2 pp 184ndash194 2018

[11] B Minasny and A E Hartemink ldquoPredicting soil propertiesin the tropicsrdquo Earth-Science Reviews vol 106 no 1-2pp 52ndash62 2011

[12] D Baros and A Albernaz ldquoPossible impacts of climate changeon wetlands and its biota in the Brazilian Amazonrdquo BrazilianJournal of Biology vol 74 no 4 pp 810ndash820 2014

[13] P Azinwi Tamfuh E Djoufac Woumfo E TemgouaA Boukong and D Bitom ldquoMoisture moisture-relatedproperties and agricultural management strategies of theBenue floodplain Vertisols in North Cameroonrdquo AfricanJournal of Agricultural Research vol 13 no 33 pp 1730ndash1746 2018

[14] IPCC (Intergovernmental Panel on Climate Change) ldquoCli-mate change 2013 the physical science basisrdquo in Contributionof Working Group I to the Fifth Assessment Report of theIntergovernmental Panel on Climate Change T F StockerD Qin G-K Plattner et al Eds Cambridge University PressCambridge UK 2013 httpwwwipccchreportar5wg1

[15] Ramsar Sites Information Service Annotated List of Wetlandsof International Importance Cameroon Ramsar Sites Infor-mation Service Gland Switzerland 2016 httpsrsisramsarorgfrris-searchlanguageframpf[0]regioncountry_fr_ss3ACameroon

Applied and Environmental Soil Science 13

Tabl

e1

Geographiccoordinatesanddetailedsoilph

ysical

characteristicsandorganicmattercontento

fBam

enda

soils

(0ndash5

0cm

depth)

S no

Long

ELatN

Altitude

Site

Particle

density

Bulk

density

Porosity

Particle

sizedistribu

tion

Coarse

fragments

Silt

sand

ratio

Silt

clay

ratio

YSO

CSO

CS

Fine

sand

Coarse

sand

Fine silt

Coarse

silt

Clay

(m)

mdashgmiddotcm

minus3

gmiddotcm

minus3

mdash

mdashmdash

Mgmiddotha

minus1

110165386

5988697

1209

Mile

4Nkw

en

24

14

4167

1219

1920

3011

123

123

6216

1030

42516

210172271

5989171

1203

24

15

4167

2122

818

319

067

067

5229

1296

58320

310175703

5988982

1208

25

15

4000

119

1721

4212

078

078

7143

1823

80493

410158177

5980301

1101

Below

Foncha

23

15

4348

1118

2021

305

128

128

6762

1621

72945

510149519

5983058

1103

23

14

4348

2212

1020

3612

087

087

5893

1864

78288

610145689

5978807

1101

24

13

4167

1710

1619

3815

092

092

6348

1621

63219

710140556

5986379

1103

24

15

4167

812

2020

4017

100

100

6838

1296

57381

810164556

5985557

1104

Mulang

24

15

4167

1219

2220

2712

193

193

6161

567

25163

910182545

5985485

1103

24

13

4167

1812

1522

3312

114

114

6250

1418

54384

1010135003

5985485

1104

23

14

4348

613

912

6021

058

058

6694

1742

71906

111013429

5979775

1104

24

16

4167

1221

1311

4312

056

056

5982

810

38149

1210159417

5975206

1102

23

14

4348

1222

919

379

060

060

6019

1418

58544

1310154991

5983772

1102

Ngomgh

am

25

15

4000

1317

2920

2912

196

196

6500

770

34650

1410144283

597592

1103

23

14

4348

1112

1120

4614

055

055

6754

1823

75211

1510139715

5990339

1102

24

15

4167

913

1916

433

071

071

7573

1134

50117

161016941

5987627

1102

23

16

4348

1113

1615

407

072

072

6961

1621

76563

1710161844

5968353

1103

24

15

4167

1222

2710

2925

162

162

5280

770

34023

1810145996

5981488

1105

Ntamulun

g23

15

4348

159

1220

449

078

078

6972

1580

69870

1910134718

5992481

1106

23

14

4348

1914

1220

3521

093

093

5537

1175

48496

2010178336

599321

1104

23

14

4348

1912

1015

443

068

068

6699

1945

80277

Yslit+

clayto

tale

arth

times100

where

totale

arth

sand

+silt+

clay

+coarse

fragments

6 Applied and Environmental Soil Science

mean value stood at 4808 and the CV was 140 e UWvaried between 244 and 2759emean value of unavailablewater of 848 was low showing a low CV at 510eWHCvaried between 43171 and 84722mmm meanwhile the meanvalues attained 67970mmm and the CV was 18 egravitational water content of the Bamendawetland soils rangedfrom 072 to 1352 with amean of 746 and a CVof 5471e infiltration depth (D) appeared between 265dmmiddotmminus1 and444dmmiddotmminus1 and the mean and CV were respectively383dmmiddotmminus1 and 12e natural air content of the soils at FCoscillated between 649 and 3186 with a mean of 2476 and aCV of 28

32 Correlation and Principal Component Analysis of the SoilCharacteristics ere was a positive correlation betweensand content and Dp and a negative correlation between DPand clay content (Table 5) Db was correlating negatively

with SOC while sand and clay contents showed a significantnegative correlation Clay and SOC contents showed asignificant positive correlation e coarse fragments con-tents correlated negatively with SOC and Db but positivelywith Db e siltclay ratio showed a significant positivecorrelation with Db Dp as well as sand silt and rockfragment contents but correlated negatively with SOC andclay contents Among the soil properties SOCS was posi-tively correlated with Db clay and silt-to-clay ratio butnegatively correlated with Dp sand silt coarse fragmentsand SOC contents No significant correlation was observedbetween the soil moisture characteristics and siltclay ratioe SOCS showed a positive correlation with FC PW CWand WHC and a negative correlation with HW AWR andUW

e analysis of linear correlation of soil moisturecharacteristics revealed that WP showed a significant pos-itive correlation with AWC and RAW and a significantnegative correlation with AWR and UW (Table 6) Also FCshowed a positive correlation with AWC RAW WHC andinfiltration depth (D) of the soil layer e AWR showed avery significant negative correlation with AWC RAW andWHC e AWC displayed a strong negative correlationwith UW while RAW displayed a strong negative corre-lation with UW e CW revealed a strong positive cor-relation with D Also UW showed a significant negativecorrelation with WHC

e PCA enabled observing a reduction of the 17original variables described to only three principal com-ponents (PC1 PC2 and PC3) explaining 7373 of the totalvariance explained (Table 7) us PC1 explained 4512 ofthe total variance and revealed significant loadings on WPAWR AWC RAW UW WHC clay and SOC while PC2expressed 1893 of the total variance and showed signif-icant loadings at FC CW and D (Figure 4) PC3 expressedsignificant loadings withDb and sand with a total variance of968 e PC1 was named the soil water retention factorbecause of a high factor loading of moisture characteristicswith soil colloids (clay and organic carbon) e PC2 wasreferred to as the available water factor because of high factorloading between available water capillary water and infil-tration depth e PC3 was denoted the soil compactionfactor as sand and bulk density affect soil porosity

Table 2 Summary statistics of the soil physical characteristics and organic matter content (n 20)

Parameters Dp Db PorosityParticle size distribution

Coarsefragments

Sandsiltratio

Siltclayratio

SOC SOCSFinesand

Coarsesand

Finesilt

Coarsesilt Clay

gmiddotcmminus3 gmiddotcmminus3 Mgmiddothaminus1

Minimum 230 130 4000 600 900 800 1000 2700 300 050 055 567 25163Maximum 250 160 4348 2200 2200 2900 2200 6000 2500 165 196 1945 80493Mean 236 145 4232 1360 1510 1570 1790 3790 1210 090 096 1366 59368SD 0067 0083 119 439 449 597 355 792 57700 031 044 414 17261CV 286 567 280 3200 2900 3850 19 21 4789 3400 105 3032 2907Skew 0549 minus0176 minus0464 0477 0400 0720 minus1197 0957 0521 099 1390 minus0450 minus052Kurtosis minus0548 minus0212 minus765 minus0575 minus129 minus008 027 171 027 056 098 minus092 minus085K-S stat 0284 0257 0287 0238 0226 0133 0269 0119 0203 0122 0210 0147 0282Dp particle density Db bulk density CV coefficient of variation SD standard deviation K-S stat KolmogorovndashSmirnov statistics

100 0

10

20

30

40

50

60

70

80

90

100

90

80

70

60

50

40

30

20

10

0100 90 80 70 60

sand

cl

ay

silt

50 40 30 20 10 0

1

2

3

4

5

67

8 9101112 13

Figure 3 Textural classes of the Bamenda Gleysols according to theUnited States Department of Agriculture textural classi-ficationmdashclassification according to the Soil Science Division Staff[6] (1) heavy clay (2) clay (3) sandy clay (4) clayey loam (5) siltyclayey (6) silty clay loam (7) sandy clay loam (8) loam (9) siltyloam (10) sandy loam (11) loamy sand (12) sand (13) loam

Applied and Environmental Soil Science 7

33 Soil Water Characteristic Curves Soil moisture char-acteristic curves enabled establishing the relationship be-tween the volumetric water content and soil matric potentialof the studied soil (Figure 5) using water retention data(Table 8) e curves revealed a sigmoid shape which slopedgently from the HW to UW steepened more from UW to

AW and became gentle from gravity water to complete poresaturation e Gleysols of Mile 4 Nkwen showed the lowestwater retention curve while those of Ngomgham displayedthe highest ones (Figure 5) e soils attained full watersaturation (HW+AWC+GW+AC) at a range of 5768 ofdry soil (Mile 4 Nkwen) to 9170 of dry soil (Ngomgham)

Table 3 Moisture characteristics of the Gleysols from the Bamenda Wetlands (n 20)

S no Site HW WP FC AWR AWC RAW CW UW GW AC WHC D() () () () (mmm) (mmm) (mmm) (mmm) (mmm) () (mmm) (dmm)

1Mile 4 Nkwen

912 366 4816 1156 28267 37878 2904 244 1263 649 56534 2652 72 4152 566 1508 33127 4439 394 788 227 1493 66253 3343 82 5606 6719 1113 4181 56025 4699 293 699 2719 83619 3974

Below Foncha

1776 4842 698 2138 37164 49799 5204 362 856 2632 74327 4125 1222 5568 7258 169 38754 5193 5436 468 1088 291 77507 46 222 4762 7328 2566 31767 42567 5108 346 941 3161 63533 3757 134 4592 6941 2349 35932 48148 4601 1009 434 2774 71863 418

Mulang

1232 2214 572 3506 21583 28921 4488 2274 321 1553 43166 3389 1088 4556 6247 1691 30824 41304 4559 603 392 208 61648 3210 743 5884 7267 1383 4076 54618 5324 64 976 2919 8152 40111 158 334 7049 3709 30391 40723 5469 2129 1302 2882 60781 44412 1221 4716 6262 1546 34147 45757 4141 325 207 1914 68294 34513

Ngomgham

1535 254 6834 4294 23436 31404 4999 2759 999 2834 46871 40414 1311 5886 7534 1648 40688 54522 5523 337 1175 3186 81376 41515 221 4228 6449 2221 33792 45281 4239 011 072 2282 67583 38116 939 5242 6726 1484 42361 56764 4887 545 539 2378 84722 42417 2302 27 728 458 24456 3277 4978 2278 811 3113 48911 4318

Ntamulung978 532 7324 2004 40257 53944 5346 1026 998 2976 80513 418

19 1567 415 6192 2042 31032 41583 4625 475 277 1844 62064 40420 1721 565 7421 1771 39157 5247 5700 050 1352 3073 78314 341

Table 4 Summary statistics of the soil moisture characteristics in the Bamenda wetlands (n 20)

Parameters HW WP FC AWR AWC RAW CW UW WHC D GW AC() () () () (mmm) (mmm) () () (mmm) (dmm) () ()

Minimum 720 2214 4816 1113 21583 28921 2904 011 43166 265 072 649Maximum 2302 5886 7534 4580 42361 56764 5700 2759 84722 4 44 1352 3186Mean 1372 4480 6700 2220 33985 45540 4809 848 67970 383 746 2476SD 487 1116 709 1016 6287 8424 665 825 12573 045 408 689CV 3600 2500 1100 4600 1800 1800 1400 9700 1800 1200 5500 2800Skew 059 minus066 minus115 127 minus048 minus048 minus121 133 minus048 minus106 minus014 minus119Kurtosis minus053 minus045 110 063 minus070 minus070 216 047 minus070 081 minus140 097K-S stat 013 013 016 020 013 013 012 025 013 022 013 020HW hygroscopic water WP permanent wilting point FC field capacity AWR available water reserve AWC available water content RAW readilyavailable water CW capillary water UW unavailable water WHC water-holding capacity D weighting depth AC air content GW gravity water CVcoefficient of variation SD standard deviation K-S stat KolmogorovndashSmirnov statistics

Table 5 Correlation amongst soil physical characteristics and soil organic carbon

Soil properties Dp Db Sand Silt Clay RF SOC Siltclay ratio SOCSDp 1 mdash mdash mdash mdash mdash mdash mdashDb 02 1 mdash mdash mdash mdash mdash mdash mdashSand 038 minus012 1 mdash mdash mdash mdash mdash mdashSilt 022 minus002 minus032 1 mdash mdash mdash mdashClay minus052lowast minus011 minus063lowastlowast minus041 1 mdash mdash mdash mdashRF 011 minus02 minus025 024 minus008 1 mdash mdash mdashSOC minus049lowast minus04 minus031 minus031 069lowastlowast minus026 1 mdash mdashSiltclay ratio 046lowast 01 017 080lowastlowast minus084lowastlowast 022 minus064lowastlowast 1 mdashSOCS minus048lowast 049lowast minus036 minus040 053lowastlowast minus032 minus065lowastlowast 098lowastlowast 100lowastCorrelation is significant at the 005 level lowastlowastcorrelation is significant at the 001 level

8 Applied and Environmental Soil Science

e height of the water characteristic curves shows a meanincreasing trend such that Ngomghamgt belowFonchagtMulanggtNtamulunggtMile 4 Nkwen

4 Discussion

41 Soil Moisture Storage Capacity of Gleysols as Affected byPhysical Properties and SOC e Gleysols of the Bamendawetlands were reddish brown wet and waterlogged with

reddish yellow and blue patches in the more waterloggedareas e surface aspect of the studied Gleysols is shown inFigure 6 ese properties are common to all wetland soils[28] e massive structure and high density of these soilscan be attributed to high clay content e high clay contentin turn made the soils stick to farm tools e sandsilt ratiois an index of weathering intensity according to Sharma et al[36] All the ratio values were greater than 045 typical ofmoderate weather e siltclay ratio of the Gleysols wasgt015 indicating that the soils are relatively young or gt020portraying a high degree of weathering potential [37] eseindices agreed with values of alluvial floodplain Gleysols[13]

e plant-available water content of the BamendaGleysols was very high according to GEPPA [34] Such high

Table 6 Pearson linear correlation coefficients amongst soil moisture characteristics (n 20)

Soil properties HW WP FC AWR AWC RAW CW UW WHC DHW 100 mdash mdash mdash mdash mdash mdash mdash mdash mdashWP minus032 100 mdash mdash mdash mdash mdash mdash mdash mdashFC 036 045 100 mdash mdash mdash mdash mdash mdash mdashAWR 059lowast minus078lowastlowast 020 100 mdash mdash mdash mdash mdash mdashAWC minus036 095lowastlowast 046lowast minus073lowastlowast 100 mdash mdash mdash mdash mdashRAW minus036 095lowastlowast 046lowastlowast minus073lowastlowast 099lowastlowast 100 mdash mdash mdash mdashCW 025 037 092lowastlowast 024 038 038 100 mdash mdash mdashUW 014 minus078lowastlowast 004 088lowastlowast minus068lowastlowast minus068lowastlowast 014 100 mdash mdashWHC minus036 minus036 046lowast -073lowastlowast 100 100 038 minus068lowastlowast 100 mdashD 027 013 074lowastlowast 037 029 036 070lowastlowast 030 029 100Dp 012 054lowast 031 037 052lowast 052lowast 035 038 minus052lowast minus017Db 002 minus037 minus009 034 minus008 minus008 minus001 041 minus008 047lowastSand 004 minus057lowast minus048lowast 028 minus054lowast minus054lowast minus047lowast 033 minus054lowast 048lowastSilt 029 minus048lowast minus005 049lowast minus045 minus045 minus006 042 minus044 minus051lowastClay minus034 081lowastlowast 027 minus070lowast 081lowastlowast 081lowastlowast 019 minus066lowastlowast 081lowastlowast 022RF 015 minus001 039 029 minus010 minus010 033 026 minus010 007SOC minus035 085lowastlowast 039 -066lowast 081lowastlowast 081lowastlowast 031 minus061lowastlowast 081lowastlowast 025Siltclay ratio 044 004 minus006 minus008 007 007 minus020 minus035 007 minus014SOCS minus035 096lowastlowast 045 minus082lowastlowast 094lowastlowast 094lowastlowast 037 minus079lowastlowast 094lowastlowast 005lowastCorrelation is significant at the 005 level lowastlowastcorrelation is significant at the 001 level

Table 7 Principal component analysis generated based on factorloading (n 20)

Soil properties PC1 PC2 PC3HW minus036 048 023WP 098 minus001 011FC 042 084 028AWR minus079 059 007AWC 097 008 minus013RAW 097 008 minus013CW 036 081 029UW minus076 044 minus005WHC 097 008 -013D 020 086 minus023Dp minus061 minus011 019Db minus028 032 minus072Sand minus059 minus038 074Silt 011 minus057 051Clay 087 minus-001 minus024RF minus010 046 033SOC 089 minus001 008Total loadinga 1175 65 194 variance explained 4512 1893 968Cumulative variance explained 4512 1893 7373RF coarse fragments extraction method principal component analysisaSums of loadings PC1 PC2 and PC3 are the first second and thirdprincipal components

0

1

075

05

025

ndash025

ndash05

ndash075

ndash1ndash1 ndash075 ndash05 ndash025 0 025 05 075 1

AWR HW RF

D CWFC

AWC RAW WHC

Clay SOC WP

Silt

Sand

Dp

Db

UW

Variables (axes F1 and F2 6404)

F2 (1

893

)

F1 (4512)

Figure 4 Graphical representation of the first two principalcomponents of soil and moisture characteristics Extractionmethod principal component analysis (n 20)

Applied and Environmental Soil Science 9

values have already been reported in some wetland soils ofNorth Cameroon [13] Also comparatively lower availablewater contents have also been reported elsewhere such as11000mmm in Australia [38] 12500mmm in Sudan [39]and 23000mmm in India [40] e difference is oftenattributed to soil texture climate and topographic positions[9 10]

e WHC values for soils from 95 of the samplingpoints of the Bamenda Gleysols were very high(gt600mmm) and comparable with values of somewetland soil in North Cameroon [13] us Gleysolsdominated by silt and sand have low WHC values while

clay-rich ones show high WHC values [38] e highvalues of RAW observed in most of the studied soils are afunction of the soil texture and the organic mattercontents of the Gleysols

e air capacity of the studied Gleysols was highcompared to the optimum root aeration value of 1000 andthe critical value of 500 required for optimum plantperformance [40] Such high air contents indicate high freewater potential So most of the water that infiltrates intopores is retained in the profiles and induces soil imper-meability surface ponding poor aeration and floods in therainy season [41]

Mile 4 Nkwen

Below Foncha

Mulang

Ngomgham

Ntamulung

Oven-dry Moist Wet

Gravity water

Gravity water

Soil water potential (kPa log scale)

Wat

er co

nten

t (

wat

er1

00g

of d

ry so

il)

Capillary water

Plant-available waterUnavailable water

Hygroscopicwater HC WP FC

0ndash1ndash10ndash100ndash1000ndash10000ndash1000000

10

20

30

40

50

60

70

80

90

Figure 5 Mean moisture retention curve of the Gleysols from different studied sites in the Bamenda wetlands HC hygroscopic coefficientWP moisture content at permanent wilting point FC moisture content at field capacity

Table 8 Cumulative soil moisture contents (in of dry soil) used to model the water characteristic curves of the Gleysols in the Bamendawetlands

Properties HW UW UW+AWR UW+AWR+GW UW+AWR+GW+ACMile 4 Nkwen (n 3) 817 2159 2718 4148 5768Below Foncha (n 4) 1640 2186 4372 5202 8072Mulang (n 5) 1173 2367 4939 5579 7849Ngomgham (n 5) 166 2846 5691 6411 9170Ntamulung (n 3) 1422 1939 3878 4753 7384Mean (n 20) 1372 2300 4460 5220 7650HW hygroscopic water content UW unavailable water content AWR available water reserve CW capillary water content GW gravity water content ACair content n number of samples

10 Applied and Environmental Soil Science

e soil moisture characteristics increased considerablyfrom upstream at Mile 4 Nkwen to downstream atNgomgham Mulang below Foncha and Ntamulung ismight be related to transport and deposition of fine earthmaterial from upstream to downstream and to the geo-morphological configuration of the studied site or even tospecific soil characteristics like the mineralogical composi-tion of the clayey fraction Also several soil internal factorsmay be responsible for the variation in the soil moistureretention curve per site such as nonuniformity of porescontact angle difference and entrapped air in pore space[42]

e capillary water of the wetland soils was high as thiswater fraction is held to soil particles by weak surface tensionforces of soil particles and is thus available to plants Duringconditions of water stress (particularly during the dry season)capillarity plays a vital role in maintaining crop performancee soil water loss is faster at the surface than at depth causinga higher water tension at the surface than at depth [43 44] Itcauses a higher water tension at the surface than at depth andthis creates a water capillary current which moves from baseto surface and hence water rises to the surface to be availableto plants [45 46]e FC andWP are primarily influenced byirregular pore geometry and discontinuity and variations intexture and mineralogy [47ndash50]

In this study clay content of the soils correlated best withthe moisture characteristics more than any other propertye clay and SOC contents probably linked together asrevealed by their significant positive correlation favor theoccurrence of micropores and menisci that generate capil-lary forcesus they increase the specific surface area of thesoil matrix and consequently water adsorption [48] Al-though siltclay ratio displays no significant correlation withsoil moisture characteristics it negatively strongly correlateswith SOC e size and structure of clay particles were moresuitable for association with SOM molecules than the sizeand the structure of bigger soil particles [49] e clay andSOC contents are indispensable in the water and nutrientretention for plants based on their high specific surface area[50] Sand and coarse fragments contents tend to increasesoil particle density thereby increasing macroporosity and

reducing microporosity hence lowering the soil capacity toretain water [51] us low correlation coefficients betweensand and coarse fragments contents and WHC are docu-mented [52 53] meanwhile the negative correlation be-tween SOC and silt content is not in line with some results[44]

e statistical analysis of the studied soil propertiesfollowed a log-normal distribution as revealed by the co-efficient of kurtosis and skewness indicating possible an-thropogenic disturbances Under natural grasslands manysoil variables tend to conform to normal distribution due tothe homogenization effect of biotic factors [54] Followingirrigation or rainfall that saturates the soil making its watercontent higher than FC there should normally be adownward movement of water by gravity action Infiltrationis related to hydraulic conductivity that leads to decrease insoil moisture content as infiltration leads to soil water loss

42 Implications of theGleysolsCharacteristics onAgriculturalManagement Strategies In the Bamenda wetlands waterlosses often attain WP in the dry season making plant-available water contents low is condition of water stresshas been reported to cause drastic decrease in yields inwetlands [55] erefore for irrigation the ldquoplant readilyavailable waterrdquo constitutes the ideal operating range of soilmoisture for irrigation management [29 56] us irriga-tion scheduling should involve the replacement of depletedwater not higher than the FC to avoid waterlogging in thesesoils as drainage andor deep percolation is poor But sincethe soils are flooded in the rainy season it implies that theirwater content is above the FC and thus necessitating thedrainage of excess water during farming in the rainy seasone soil water characteristic curves become an indispensableto design irrigation schedules especially in the dry seasonduring moisture deficiency or to drain excess water in therainy season [57ndash59]

To achieve high yields without creating excess drainageit is necessary to know the crop readily available to becultivated After readily available water has been used plantroots cannot easily extract water and nutrients from the soil

Table 9 List of Ramsar sites in Cameroon [15]

SN Site Ramsar

identifierDesignation

date Region Geographic coordinates Altitude(m)

Surface area(km2)

1 Waza-Logone floodplain 1609 26052006 ExtremeNorth

11deg 37prime 59primeNorth14deg 37prime 01prime East 300 6000

2 Barombi-Mbo Lake 1643 810rsquo2006 South west 4deg 40prime 01primeNorth9deg 22prime 59primeEast 301ndash400 415

3 Cameroon section of theSangha River 1739 2022008 East 1deg 49prime 59primeNorth

16deg 01prime 59primeEast 350ndash700 62

4 Cameroon section of LakeChad 1903 2022010 Extreme

North12deg 46prime 01primeNorth14deg18prime 00primeEast 160ndash280 125

5 Rio Del Rey Estuary 1908 20052010 South West 4deg 37prime 01primeNorth8deg 43prime 01prime East 5 1650

6 Cameroon section of theNtem River 2067 5062012 South 2deg 22prime 44primeNorth

10deg 33prime14primeEast 400ndash526 39848

7 Ebogo Humid Zone 2028 605 2012 Centre 3deg 23prime10primeNorth11deg 29prime 20primeEast 630ndash670 3097

Applied and Environmental Soil Science 11

and this is the time to irrigate or refill pointe drier the soilis the more water it needs to return to field capacityus inirrigation FC and refill point are critical values for thecorrect use of many of the soil water monitoring

e high clay content of the Gleysols in the Bamendawetlands makes tillage and weed control in these areasdifficult due to the presence of water and sticky nature ofsoils to farm tools e high bulk density of the Gleysols isvery high (16 gmiddotcmminus3) compared to the optimum value(133 gmiddotcmminus3) for root penetration but also close to the upperlimit (175 gmiddotcmminus3) for root growth and is therefore a lim-iting factor to agriculture [60] High bulk density impliesthat the soils are not well aerated as most of the pores aresaturated with water during wet conditions

e highly significant correlation between clay and or-ganic matter contents reveals that both are linked together toform organo-mineral complexes and thus the SOC is beingprotected by soil matrix ese two soil colloids play a vital

role in the retention of water and nutrients for crop needs asrevealed by their high correlation with most of the moisturecharacteristicse high SOC implies a high cation exchangecapacity (CEC) e overall CEC of SOC and clay contentsfavors the retention and availability of nutrients to maintaincrop production in those Gleysols [60ndash62]

Particle size distribution also conditions chemical nu-trient supply [63] Most of the studied Gleysols samples haveclay plus silt content greater than 35 this indicates poornutrient assimilation by plants A correlation has also beenestablished between particle size distribution and yields [63]e (silt + sand)-to-total earth ratios of the Gleysols werevery high (gtgt35) relative to the ratio range of 15 to 35necessary for optimum yields and indicate potentially pooryields for a majority of tropical crops [63]

e SOCS of the Bamenda wetlands Gleysols is very high(gt200Mgmiddothaminus1) as such wetlands especially floodplains areoften very productive [4] Such ecosystems have the ability of

(a) (b)

(c) (d)

(e) (f )

Figure 6 Photographs of wetland ecosystems in Nkwen (Bamenda) (a) Wetland with grassed vegetation (b) water retained in furrows ofraised ridges (c d) channeling of water into farmlands for irrigation (e f ) healthy maize crops cultivated in the wetlands of Bamenda

12 Applied and Environmental Soil Science

sequestering and storing carbon through photosynthesis andorganic matter accumulation in soils and plant biomassthereby offering the opportunity for regaining lost pro-ductivity especially under agricultural systems e prop-erties of these studied soils could be similar to those of someRamsar sites in Cameroon although with some site specificfeatures Table 9 shows different Ramsar sites in Cameroon

5 Conclusion

In Bamenda City (Northwest Cameroon) population in-crease has led to considerable lawless occupation of wetlandsespecially as these areas are very fertile and support year-round agriculture Land use is often done without necessarytechnical know-how of sustainable land managementtechniques is work was focused on the determination ofmoisture characteristics of Gleysols in the Bamenda wet-lands and to establish a link between them and selected soilcharacteristics affecting crop production

e major findings revealed that the Gleysols showedvery high organic carbon contents and very high soil organiccarbon stocks implying a high level of carbon sequestrationMajor constraints of the soils to farming were clay plus siltcontents massive structure and waterlogging e moistureproperties revealed very high water-holding capacity andvery high plant-available water e particle density andcoarse fragments and sand contents correlated negativelywith the soil moisture retention characteristics and could bereducing the soilrsquos water-holding capacity e soil moisturecharacteristics curves were sigmoid-shaped and their heightsdecreased from upstream to downstream probably por-traying increase of finer material with fluvial transportdistant

e present work might have been limited in terms ofthe inadequate number of samples studied Further re-search is necessary on these wetland soils of the northwestregion of Cameroon to evaluate their potential risk ofdegradation based on a higher number of samples Alsothe results presented in this work might have been biasedbased on the fact that the tests were conducted solely inthe laboratory In the future measurements of waterstorage capacity of these soils should be done directly inthe field using more accurate methods such as electricalresistance and tensiometric and heat-diffusion methodsIrrigation schedules on this these soils should involve thereplacement of depleted water with water amounts notexceeding the FC to avoid waterlogging in these soils asdrainage andor deep percolation is poor Adapted cropslike lowland rice could also be introduced to extend thesurfaces of rice cultivation in the zone

Data Availability

Data can be made available on request

Conflicts of Interest

e authors declare no conflicts of interest

References

[1] W J Rawls T J Gish and D L Brakensiek ldquoEstimating soilwater retention from soil physical properties and character-isticsrdquoAdvances in Soil Science vol 16 pp 213ndash234 Springer-Verlag New York Inc NY USA 1991

[2] E Kellner and S Halldin ldquoWater budget and surface-layerwater storage in a Sphagnum bog in central Swedenrdquo Hy-drological Processes vol 16 no 1 pp 87ndash103 2002

[3] R M Khalid and H A K Ahmed ldquoNature of soil-watercharacteristics curves (SWCC) for soils from Anbar Gover-noraterdquo Anbar Journal of Engineering Sciences vol 3 no 1pp 61ndash80 2010

[4] e Ramsar Convention on Wetlands ldquoClimate Change andWetlands Resolution X24rdquo in Proceedings of the 10thMeeting of the Conference of the Parties to the Convention onWetlands Changwon Republic of Korea October 2008httpswwwramsarorgdocumentresolution-x24-climate-change-and-wetlands

[5] J Vopravil P Formanek and T Khel ldquoComparison of thephysical properties of soils belonging to different referencesoil groupsrdquo Soil andWater Research vol 16 pp 29ndash38 2021

[6] USDA Soil Survey Manual USDA Washington D C USA2017

[7] S R Carpenter W A Brock and P Hanson ldquoResilientmanagement comments onrdquo Ecological and Social Dynamics inSimple Models of EcosystemManagement Conservation EcologyResilience Alliance vol 3 no 2 Wisconsin USA 1999

[8] K E Saxton and W J Rawls ldquoSoil water characteristic es-timates by texture and organic matter for hydrologic solu-tionsrdquo Soil Science Society of America Journal vol 70 no 5pp 1569ndash1578 2006

[9] P A Tamfuh A H Chotangui A H Chotangui et al ldquoLandcharacteristics and agricultural suitability status along a top-osequence in Santa Bamenda Highlands Cameroonrdquo Journalof Atmospheric amp Earth Science vol 4 no 1 pp 1ndash9 2020

[10] A Kagou Dongmo C S Guedjeo P Azinwi Tamfuh et alldquoGeochemical and geotechnical characterization of soils de-veloped on volcanic rocks in the Bamenda Mountain(Cameroon volcanic line)rdquo International Journal of AdvancedGeosciences vol 6 no 2 pp 184ndash194 2018

[11] B Minasny and A E Hartemink ldquoPredicting soil propertiesin the tropicsrdquo Earth-Science Reviews vol 106 no 1-2pp 52ndash62 2011

[12] D Baros and A Albernaz ldquoPossible impacts of climate changeon wetlands and its biota in the Brazilian Amazonrdquo BrazilianJournal of Biology vol 74 no 4 pp 810ndash820 2014

[13] P Azinwi Tamfuh E Djoufac Woumfo E TemgouaA Boukong and D Bitom ldquoMoisture moisture-relatedproperties and agricultural management strategies of theBenue floodplain Vertisols in North Cameroonrdquo AfricanJournal of Agricultural Research vol 13 no 33 pp 1730ndash1746 2018

[14] IPCC (Intergovernmental Panel on Climate Change) ldquoCli-mate change 2013 the physical science basisrdquo in Contributionof Working Group I to the Fifth Assessment Report of theIntergovernmental Panel on Climate Change T F StockerD Qin G-K Plattner et al Eds Cambridge University PressCambridge UK 2013 httpwwwipccchreportar5wg1

[15] Ramsar Sites Information Service Annotated List of Wetlandsof International Importance Cameroon Ramsar Sites Infor-mation Service Gland Switzerland 2016 httpsrsisramsarorgfrris-searchlanguageframpf[0]regioncountry_fr_ss3ACameroon

Applied and Environmental Soil Science 13

mean value stood at 4808 and the CV was 140 e UWvaried between 244 and 2759emean value of unavailablewater of 848 was low showing a low CV at 510eWHCvaried between 43171 and 84722mmm meanwhile the meanvalues attained 67970mmm and the CV was 18 egravitational water content of the Bamendawetland soils rangedfrom 072 to 1352 with amean of 746 and a CVof 5471e infiltration depth (D) appeared between 265dmmiddotmminus1 and444dmmiddotmminus1 and the mean and CV were respectively383dmmiddotmminus1 and 12e natural air content of the soils at FCoscillated between 649 and 3186 with a mean of 2476 and aCV of 28

32 Correlation and Principal Component Analysis of the SoilCharacteristics ere was a positive correlation betweensand content and Dp and a negative correlation between DPand clay content (Table 5) Db was correlating negatively

with SOC while sand and clay contents showed a significantnegative correlation Clay and SOC contents showed asignificant positive correlation e coarse fragments con-tents correlated negatively with SOC and Db but positivelywith Db e siltclay ratio showed a significant positivecorrelation with Db Dp as well as sand silt and rockfragment contents but correlated negatively with SOC andclay contents Among the soil properties SOCS was posi-tively correlated with Db clay and silt-to-clay ratio butnegatively correlated with Dp sand silt coarse fragmentsand SOC contents No significant correlation was observedbetween the soil moisture characteristics and siltclay ratioe SOCS showed a positive correlation with FC PW CWand WHC and a negative correlation with HW AWR andUW

e analysis of linear correlation of soil moisturecharacteristics revealed that WP showed a significant pos-itive correlation with AWC and RAW and a significantnegative correlation with AWR and UW (Table 6) Also FCshowed a positive correlation with AWC RAW WHC andinfiltration depth (D) of the soil layer e AWR showed avery significant negative correlation with AWC RAW andWHC e AWC displayed a strong negative correlationwith UW while RAW displayed a strong negative corre-lation with UW e CW revealed a strong positive cor-relation with D Also UW showed a significant negativecorrelation with WHC

e PCA enabled observing a reduction of the 17original variables described to only three principal com-ponents (PC1 PC2 and PC3) explaining 7373 of the totalvariance explained (Table 7) us PC1 explained 4512 ofthe total variance and revealed significant loadings on WPAWR AWC RAW UW WHC clay and SOC while PC2expressed 1893 of the total variance and showed signif-icant loadings at FC CW and D (Figure 4) PC3 expressedsignificant loadings withDb and sand with a total variance of968 e PC1 was named the soil water retention factorbecause of a high factor loading of moisture characteristicswith soil colloids (clay and organic carbon) e PC2 wasreferred to as the available water factor because of high factorloading between available water capillary water and infil-tration depth e PC3 was denoted the soil compactionfactor as sand and bulk density affect soil porosity

Table 2 Summary statistics of the soil physical characteristics and organic matter content (n 20)

Parameters Dp Db PorosityParticle size distribution

Coarsefragments

Sandsiltratio

Siltclayratio

SOC SOCSFinesand

Coarsesand

Finesilt

Coarsesilt Clay

gmiddotcmminus3 gmiddotcmminus3 Mgmiddothaminus1

Minimum 230 130 4000 600 900 800 1000 2700 300 050 055 567 25163Maximum 250 160 4348 2200 2200 2900 2200 6000 2500 165 196 1945 80493Mean 236 145 4232 1360 1510 1570 1790 3790 1210 090 096 1366 59368SD 0067 0083 119 439 449 597 355 792 57700 031 044 414 17261CV 286 567 280 3200 2900 3850 19 21 4789 3400 105 3032 2907Skew 0549 minus0176 minus0464 0477 0400 0720 minus1197 0957 0521 099 1390 minus0450 minus052Kurtosis minus0548 minus0212 minus765 minus0575 minus129 minus008 027 171 027 056 098 minus092 minus085K-S stat 0284 0257 0287 0238 0226 0133 0269 0119 0203 0122 0210 0147 0282Dp particle density Db bulk density CV coefficient of variation SD standard deviation K-S stat KolmogorovndashSmirnov statistics

100 0

10

20

30

40

50

60

70

80

90

100

90

80

70

60

50

40

30

20

10

0100 90 80 70 60

sand

cl

ay

silt

50 40 30 20 10 0

1

2

3

4

5

67

8 9101112 13

Figure 3 Textural classes of the Bamenda Gleysols according to theUnited States Department of Agriculture textural classi-ficationmdashclassification according to the Soil Science Division Staff[6] (1) heavy clay (2) clay (3) sandy clay (4) clayey loam (5) siltyclayey (6) silty clay loam (7) sandy clay loam (8) loam (9) siltyloam (10) sandy loam (11) loamy sand (12) sand (13) loam

Applied and Environmental Soil Science 7

33 Soil Water Characteristic Curves Soil moisture char-acteristic curves enabled establishing the relationship be-tween the volumetric water content and soil matric potentialof the studied soil (Figure 5) using water retention data(Table 8) e curves revealed a sigmoid shape which slopedgently from the HW to UW steepened more from UW to

AW and became gentle from gravity water to complete poresaturation e Gleysols of Mile 4 Nkwen showed the lowestwater retention curve while those of Ngomgham displayedthe highest ones (Figure 5) e soils attained full watersaturation (HW+AWC+GW+AC) at a range of 5768 ofdry soil (Mile 4 Nkwen) to 9170 of dry soil (Ngomgham)

Table 3 Moisture characteristics of the Gleysols from the Bamenda Wetlands (n 20)

S no Site HW WP FC AWR AWC RAW CW UW GW AC WHC D() () () () (mmm) (mmm) (mmm) (mmm) (mmm) () (mmm) (dmm)

1Mile 4 Nkwen

912 366 4816 1156 28267 37878 2904 244 1263 649 56534 2652 72 4152 566 1508 33127 4439 394 788 227 1493 66253 3343 82 5606 6719 1113 4181 56025 4699 293 699 2719 83619 3974

Below Foncha

1776 4842 698 2138 37164 49799 5204 362 856 2632 74327 4125 1222 5568 7258 169 38754 5193 5436 468 1088 291 77507 46 222 4762 7328 2566 31767 42567 5108 346 941 3161 63533 3757 134 4592 6941 2349 35932 48148 4601 1009 434 2774 71863 418

Mulang

1232 2214 572 3506 21583 28921 4488 2274 321 1553 43166 3389 1088 4556 6247 1691 30824 41304 4559 603 392 208 61648 3210 743 5884 7267 1383 4076 54618 5324 64 976 2919 8152 40111 158 334 7049 3709 30391 40723 5469 2129 1302 2882 60781 44412 1221 4716 6262 1546 34147 45757 4141 325 207 1914 68294 34513

Ngomgham

1535 254 6834 4294 23436 31404 4999 2759 999 2834 46871 40414 1311 5886 7534 1648 40688 54522 5523 337 1175 3186 81376 41515 221 4228 6449 2221 33792 45281 4239 011 072 2282 67583 38116 939 5242 6726 1484 42361 56764 4887 545 539 2378 84722 42417 2302 27 728 458 24456 3277 4978 2278 811 3113 48911 4318

Ntamulung978 532 7324 2004 40257 53944 5346 1026 998 2976 80513 418

19 1567 415 6192 2042 31032 41583 4625 475 277 1844 62064 40420 1721 565 7421 1771 39157 5247 5700 050 1352 3073 78314 341

Table 4 Summary statistics of the soil moisture characteristics in the Bamenda wetlands (n 20)

Parameters HW WP FC AWR AWC RAW CW UW WHC D GW AC() () () () (mmm) (mmm) () () (mmm) (dmm) () ()

Minimum 720 2214 4816 1113 21583 28921 2904 011 43166 265 072 649Maximum 2302 5886 7534 4580 42361 56764 5700 2759 84722 4 44 1352 3186Mean 1372 4480 6700 2220 33985 45540 4809 848 67970 383 746 2476SD 487 1116 709 1016 6287 8424 665 825 12573 045 408 689CV 3600 2500 1100 4600 1800 1800 1400 9700 1800 1200 5500 2800Skew 059 minus066 minus115 127 minus048 minus048 minus121 133 minus048 minus106 minus014 minus119Kurtosis minus053 minus045 110 063 minus070 minus070 216 047 minus070 081 minus140 097K-S stat 013 013 016 020 013 013 012 025 013 022 013 020HW hygroscopic water WP permanent wilting point FC field capacity AWR available water reserve AWC available water content RAW readilyavailable water CW capillary water UW unavailable water WHC water-holding capacity D weighting depth AC air content GW gravity water CVcoefficient of variation SD standard deviation K-S stat KolmogorovndashSmirnov statistics

Table 5 Correlation amongst soil physical characteristics and soil organic carbon

Soil properties Dp Db Sand Silt Clay RF SOC Siltclay ratio SOCSDp 1 mdash mdash mdash mdash mdash mdash mdashDb 02 1 mdash mdash mdash mdash mdash mdash mdashSand 038 minus012 1 mdash mdash mdash mdash mdash mdashSilt 022 minus002 minus032 1 mdash mdash mdash mdashClay minus052lowast minus011 minus063lowastlowast minus041 1 mdash mdash mdash mdashRF 011 minus02 minus025 024 minus008 1 mdash mdash mdashSOC minus049lowast minus04 minus031 minus031 069lowastlowast minus026 1 mdash mdashSiltclay ratio 046lowast 01 017 080lowastlowast minus084lowastlowast 022 minus064lowastlowast 1 mdashSOCS minus048lowast 049lowast minus036 minus040 053lowastlowast minus032 minus065lowastlowast 098lowastlowast 100lowastCorrelation is significant at the 005 level lowastlowastcorrelation is significant at the 001 level

8 Applied and Environmental Soil Science

e height of the water characteristic curves shows a meanincreasing trend such that Ngomghamgt belowFonchagtMulanggtNtamulunggtMile 4 Nkwen

4 Discussion

41 Soil Moisture Storage Capacity of Gleysols as Affected byPhysical Properties and SOC e Gleysols of the Bamendawetlands were reddish brown wet and waterlogged with

reddish yellow and blue patches in the more waterloggedareas e surface aspect of the studied Gleysols is shown inFigure 6 ese properties are common to all wetland soils[28] e massive structure and high density of these soilscan be attributed to high clay content e high clay contentin turn made the soils stick to farm tools e sandsilt ratiois an index of weathering intensity according to Sharma et al[36] All the ratio values were greater than 045 typical ofmoderate weather e siltclay ratio of the Gleysols wasgt015 indicating that the soils are relatively young or gt020portraying a high degree of weathering potential [37] eseindices agreed with values of alluvial floodplain Gleysols[13]

e plant-available water content of the BamendaGleysols was very high according to GEPPA [34] Such high

Table 6 Pearson linear correlation coefficients amongst soil moisture characteristics (n 20)

Soil properties HW WP FC AWR AWC RAW CW UW WHC DHW 100 mdash mdash mdash mdash mdash mdash mdash mdash mdashWP minus032 100 mdash mdash mdash mdash mdash mdash mdash mdashFC 036 045 100 mdash mdash mdash mdash mdash mdash mdashAWR 059lowast minus078lowastlowast 020 100 mdash mdash mdash mdash mdash mdashAWC minus036 095lowastlowast 046lowast minus073lowastlowast 100 mdash mdash mdash mdash mdashRAW minus036 095lowastlowast 046lowastlowast minus073lowastlowast 099lowastlowast 100 mdash mdash mdash mdashCW 025 037 092lowastlowast 024 038 038 100 mdash mdash mdashUW 014 minus078lowastlowast 004 088lowastlowast minus068lowastlowast minus068lowastlowast 014 100 mdash mdashWHC minus036 minus036 046lowast -073lowastlowast 100 100 038 minus068lowastlowast 100 mdashD 027 013 074lowastlowast 037 029 036 070lowastlowast 030 029 100Dp 012 054lowast 031 037 052lowast 052lowast 035 038 minus052lowast minus017Db 002 minus037 minus009 034 minus008 minus008 minus001 041 minus008 047lowastSand 004 minus057lowast minus048lowast 028 minus054lowast minus054lowast minus047lowast 033 minus054lowast 048lowastSilt 029 minus048lowast minus005 049lowast minus045 minus045 minus006 042 minus044 minus051lowastClay minus034 081lowastlowast 027 minus070lowast 081lowastlowast 081lowastlowast 019 minus066lowastlowast 081lowastlowast 022RF 015 minus001 039 029 minus010 minus010 033 026 minus010 007SOC minus035 085lowastlowast 039 -066lowast 081lowastlowast 081lowastlowast 031 minus061lowastlowast 081lowastlowast 025Siltclay ratio 044 004 minus006 minus008 007 007 minus020 minus035 007 minus014SOCS minus035 096lowastlowast 045 minus082lowastlowast 094lowastlowast 094lowastlowast 037 minus079lowastlowast 094lowastlowast 005lowastCorrelation is significant at the 005 level lowastlowastcorrelation is significant at the 001 level

Table 7 Principal component analysis generated based on factorloading (n 20)

Soil properties PC1 PC2 PC3HW minus036 048 023WP 098 minus001 011FC 042 084 028AWR minus079 059 007AWC 097 008 minus013RAW 097 008 minus013CW 036 081 029UW minus076 044 minus005WHC 097 008 -013D 020 086 minus023Dp minus061 minus011 019Db minus028 032 minus072Sand minus059 minus038 074Silt 011 minus057 051Clay 087 minus-001 minus024RF minus010 046 033SOC 089 minus001 008Total loadinga 1175 65 194 variance explained 4512 1893 968Cumulative variance explained 4512 1893 7373RF coarse fragments extraction method principal component analysisaSums of loadings PC1 PC2 and PC3 are the first second and thirdprincipal components

0

1

075

05

025

ndash025

ndash05

ndash075

ndash1ndash1 ndash075 ndash05 ndash025 0 025 05 075 1

AWR HW RF

D CWFC

AWC RAW WHC

Clay SOC WP

Silt

Sand

Dp

Db

UW

Variables (axes F1 and F2 6404)

F2 (1

893

)

F1 (4512)

Figure 4 Graphical representation of the first two principalcomponents of soil and moisture characteristics Extractionmethod principal component analysis (n 20)

Applied and Environmental Soil Science 9

values have already been reported in some wetland soils ofNorth Cameroon [13] Also comparatively lower availablewater contents have also been reported elsewhere such as11000mmm in Australia [38] 12500mmm in Sudan [39]and 23000mmm in India [40] e difference is oftenattributed to soil texture climate and topographic positions[9 10]

e WHC values for soils from 95 of the samplingpoints of the Bamenda Gleysols were very high(gt600mmm) and comparable with values of somewetland soil in North Cameroon [13] us Gleysolsdominated by silt and sand have low WHC values while

clay-rich ones show high WHC values [38] e highvalues of RAW observed in most of the studied soils are afunction of the soil texture and the organic mattercontents of the Gleysols

e air capacity of the studied Gleysols was highcompared to the optimum root aeration value of 1000 andthe critical value of 500 required for optimum plantperformance [40] Such high air contents indicate high freewater potential So most of the water that infiltrates intopores is retained in the profiles and induces soil imper-meability surface ponding poor aeration and floods in therainy season [41]

Mile 4 Nkwen

Below Foncha

Mulang

Ngomgham

Ntamulung

Oven-dry Moist Wet

Gravity water

Gravity water

Soil water potential (kPa log scale)

Wat

er co

nten

t (

wat

er1

00g

of d

ry so

il)

Capillary water

Plant-available waterUnavailable water

Hygroscopicwater HC WP FC

0ndash1ndash10ndash100ndash1000ndash10000ndash1000000

10

20

30

40

50

60

70

80

90

Figure 5 Mean moisture retention curve of the Gleysols from different studied sites in the Bamenda wetlands HC hygroscopic coefficientWP moisture content at permanent wilting point FC moisture content at field capacity

Table 8 Cumulative soil moisture contents (in of dry soil) used to model the water characteristic curves of the Gleysols in the Bamendawetlands

Properties HW UW UW+AWR UW+AWR+GW UW+AWR+GW+ACMile 4 Nkwen (n 3) 817 2159 2718 4148 5768Below Foncha (n 4) 1640 2186 4372 5202 8072Mulang (n 5) 1173 2367 4939 5579 7849Ngomgham (n 5) 166 2846 5691 6411 9170Ntamulung (n 3) 1422 1939 3878 4753 7384Mean (n 20) 1372 2300 4460 5220 7650HW hygroscopic water content UW unavailable water content AWR available water reserve CW capillary water content GW gravity water content ACair content n number of samples

10 Applied and Environmental Soil Science

e soil moisture characteristics increased considerablyfrom upstream at Mile 4 Nkwen to downstream atNgomgham Mulang below Foncha and Ntamulung ismight be related to transport and deposition of fine earthmaterial from upstream to downstream and to the geo-morphological configuration of the studied site or even tospecific soil characteristics like the mineralogical composi-tion of the clayey fraction Also several soil internal factorsmay be responsible for the variation in the soil moistureretention curve per site such as nonuniformity of porescontact angle difference and entrapped air in pore space[42]

e capillary water of the wetland soils was high as thiswater fraction is held to soil particles by weak surface tensionforces of soil particles and is thus available to plants Duringconditions of water stress (particularly during the dry season)capillarity plays a vital role in maintaining crop performancee soil water loss is faster at the surface than at depth causinga higher water tension at the surface than at depth [43 44] Itcauses a higher water tension at the surface than at depth andthis creates a water capillary current which moves from baseto surface and hence water rises to the surface to be availableto plants [45 46]e FC andWP are primarily influenced byirregular pore geometry and discontinuity and variations intexture and mineralogy [47ndash50]

In this study clay content of the soils correlated best withthe moisture characteristics more than any other propertye clay and SOC contents probably linked together asrevealed by their significant positive correlation favor theoccurrence of micropores and menisci that generate capil-lary forcesus they increase the specific surface area of thesoil matrix and consequently water adsorption [48] Al-though siltclay ratio displays no significant correlation withsoil moisture characteristics it negatively strongly correlateswith SOC e size and structure of clay particles were moresuitable for association with SOM molecules than the sizeand the structure of bigger soil particles [49] e clay andSOC contents are indispensable in the water and nutrientretention for plants based on their high specific surface area[50] Sand and coarse fragments contents tend to increasesoil particle density thereby increasing macroporosity and

reducing microporosity hence lowering the soil capacity toretain water [51] us low correlation coefficients betweensand and coarse fragments contents and WHC are docu-mented [52 53] meanwhile the negative correlation be-tween SOC and silt content is not in line with some results[44]

e statistical analysis of the studied soil propertiesfollowed a log-normal distribution as revealed by the co-efficient of kurtosis and skewness indicating possible an-thropogenic disturbances Under natural grasslands manysoil variables tend to conform to normal distribution due tothe homogenization effect of biotic factors [54] Followingirrigation or rainfall that saturates the soil making its watercontent higher than FC there should normally be adownward movement of water by gravity action Infiltrationis related to hydraulic conductivity that leads to decrease insoil moisture content as infiltration leads to soil water loss

42 Implications of theGleysolsCharacteristics onAgriculturalManagement Strategies In the Bamenda wetlands waterlosses often attain WP in the dry season making plant-available water contents low is condition of water stresshas been reported to cause drastic decrease in yields inwetlands [55] erefore for irrigation the ldquoplant readilyavailable waterrdquo constitutes the ideal operating range of soilmoisture for irrigation management [29 56] us irriga-tion scheduling should involve the replacement of depletedwater not higher than the FC to avoid waterlogging in thesesoils as drainage andor deep percolation is poor But sincethe soils are flooded in the rainy season it implies that theirwater content is above the FC and thus necessitating thedrainage of excess water during farming in the rainy seasone soil water characteristic curves become an indispensableto design irrigation schedules especially in the dry seasonduring moisture deficiency or to drain excess water in therainy season [57ndash59]

To achieve high yields without creating excess drainageit is necessary to know the crop readily available to becultivated After readily available water has been used plantroots cannot easily extract water and nutrients from the soil

Table 9 List of Ramsar sites in Cameroon [15]

SN Site Ramsar

identifierDesignation

date Region Geographic coordinates Altitude(m)

Surface area(km2)

1 Waza-Logone floodplain 1609 26052006 ExtremeNorth

11deg 37prime 59primeNorth14deg 37prime 01prime East 300 6000

2 Barombi-Mbo Lake 1643 810rsquo2006 South west 4deg 40prime 01primeNorth9deg 22prime 59primeEast 301ndash400 415

3 Cameroon section of theSangha River 1739 2022008 East 1deg 49prime 59primeNorth

16deg 01prime 59primeEast 350ndash700 62

4 Cameroon section of LakeChad 1903 2022010 Extreme

North12deg 46prime 01primeNorth14deg18prime 00primeEast 160ndash280 125

5 Rio Del Rey Estuary 1908 20052010 South West 4deg 37prime 01primeNorth8deg 43prime 01prime East 5 1650

6 Cameroon section of theNtem River 2067 5062012 South 2deg 22prime 44primeNorth

10deg 33prime14primeEast 400ndash526 39848

7 Ebogo Humid Zone 2028 605 2012 Centre 3deg 23prime10primeNorth11deg 29prime 20primeEast 630ndash670 3097

Applied and Environmental Soil Science 11

and this is the time to irrigate or refill pointe drier the soilis the more water it needs to return to field capacityus inirrigation FC and refill point are critical values for thecorrect use of many of the soil water monitoring

e high clay content of the Gleysols in the Bamendawetlands makes tillage and weed control in these areasdifficult due to the presence of water and sticky nature ofsoils to farm tools e high bulk density of the Gleysols isvery high (16 gmiddotcmminus3) compared to the optimum value(133 gmiddotcmminus3) for root penetration but also close to the upperlimit (175 gmiddotcmminus3) for root growth and is therefore a lim-iting factor to agriculture [60] High bulk density impliesthat the soils are not well aerated as most of the pores aresaturated with water during wet conditions

e highly significant correlation between clay and or-ganic matter contents reveals that both are linked together toform organo-mineral complexes and thus the SOC is beingprotected by soil matrix ese two soil colloids play a vital

role in the retention of water and nutrients for crop needs asrevealed by their high correlation with most of the moisturecharacteristicse high SOC implies a high cation exchangecapacity (CEC) e overall CEC of SOC and clay contentsfavors the retention and availability of nutrients to maintaincrop production in those Gleysols [60ndash62]

Particle size distribution also conditions chemical nu-trient supply [63] Most of the studied Gleysols samples haveclay plus silt content greater than 35 this indicates poornutrient assimilation by plants A correlation has also beenestablished between particle size distribution and yields [63]e (silt + sand)-to-total earth ratios of the Gleysols werevery high (gtgt35) relative to the ratio range of 15 to 35necessary for optimum yields and indicate potentially pooryields for a majority of tropical crops [63]

e SOCS of the Bamenda wetlands Gleysols is very high(gt200Mgmiddothaminus1) as such wetlands especially floodplains areoften very productive [4] Such ecosystems have the ability of

(a) (b)

(c) (d)

(e) (f )

Figure 6 Photographs of wetland ecosystems in Nkwen (Bamenda) (a) Wetland with grassed vegetation (b) water retained in furrows ofraised ridges (c d) channeling of water into farmlands for irrigation (e f ) healthy maize crops cultivated in the wetlands of Bamenda

12 Applied and Environmental Soil Science

sequestering and storing carbon through photosynthesis andorganic matter accumulation in soils and plant biomassthereby offering the opportunity for regaining lost pro-ductivity especially under agricultural systems e prop-erties of these studied soils could be similar to those of someRamsar sites in Cameroon although with some site specificfeatures Table 9 shows different Ramsar sites in Cameroon

5 Conclusion

In Bamenda City (Northwest Cameroon) population in-crease has led to considerable lawless occupation of wetlandsespecially as these areas are very fertile and support year-round agriculture Land use is often done without necessarytechnical know-how of sustainable land managementtechniques is work was focused on the determination ofmoisture characteristics of Gleysols in the Bamenda wet-lands and to establish a link between them and selected soilcharacteristics affecting crop production

e major findings revealed that the Gleysols showedvery high organic carbon contents and very high soil organiccarbon stocks implying a high level of carbon sequestrationMajor constraints of the soils to farming were clay plus siltcontents massive structure and waterlogging e moistureproperties revealed very high water-holding capacity andvery high plant-available water e particle density andcoarse fragments and sand contents correlated negativelywith the soil moisture retention characteristics and could bereducing the soilrsquos water-holding capacity e soil moisturecharacteristics curves were sigmoid-shaped and their heightsdecreased from upstream to downstream probably por-traying increase of finer material with fluvial transportdistant

e present work might have been limited in terms ofthe inadequate number of samples studied Further re-search is necessary on these wetland soils of the northwestregion of Cameroon to evaluate their potential risk ofdegradation based on a higher number of samples Alsothe results presented in this work might have been biasedbased on the fact that the tests were conducted solely inthe laboratory In the future measurements of waterstorage capacity of these soils should be done directly inthe field using more accurate methods such as electricalresistance and tensiometric and heat-diffusion methodsIrrigation schedules on this these soils should involve thereplacement of depleted water with water amounts notexceeding the FC to avoid waterlogging in these soils asdrainage andor deep percolation is poor Adapted cropslike lowland rice could also be introduced to extend thesurfaces of rice cultivation in the zone

Data Availability

Data can be made available on request

Conflicts of Interest

e authors declare no conflicts of interest

References

[1] W J Rawls T J Gish and D L Brakensiek ldquoEstimating soilwater retention from soil physical properties and character-isticsrdquoAdvances in Soil Science vol 16 pp 213ndash234 Springer-Verlag New York Inc NY USA 1991

[2] E Kellner and S Halldin ldquoWater budget and surface-layerwater storage in a Sphagnum bog in central Swedenrdquo Hy-drological Processes vol 16 no 1 pp 87ndash103 2002

[3] R M Khalid and H A K Ahmed ldquoNature of soil-watercharacteristics curves (SWCC) for soils from Anbar Gover-noraterdquo Anbar Journal of Engineering Sciences vol 3 no 1pp 61ndash80 2010

[4] e Ramsar Convention on Wetlands ldquoClimate Change andWetlands Resolution X24rdquo in Proceedings of the 10thMeeting of the Conference of the Parties to the Convention onWetlands Changwon Republic of Korea October 2008httpswwwramsarorgdocumentresolution-x24-climate-change-and-wetlands

[5] J Vopravil P Formanek and T Khel ldquoComparison of thephysical properties of soils belonging to different referencesoil groupsrdquo Soil andWater Research vol 16 pp 29ndash38 2021

[6] USDA Soil Survey Manual USDA Washington D C USA2017

[7] S R Carpenter W A Brock and P Hanson ldquoResilientmanagement comments onrdquo Ecological and Social Dynamics inSimple Models of EcosystemManagement Conservation EcologyResilience Alliance vol 3 no 2 Wisconsin USA 1999

[8] K E Saxton and W J Rawls ldquoSoil water characteristic es-timates by texture and organic matter for hydrologic solu-tionsrdquo Soil Science Society of America Journal vol 70 no 5pp 1569ndash1578 2006

[9] P A Tamfuh A H Chotangui A H Chotangui et al ldquoLandcharacteristics and agricultural suitability status along a top-osequence in Santa Bamenda Highlands Cameroonrdquo Journalof Atmospheric amp Earth Science vol 4 no 1 pp 1ndash9 2020

[10] A Kagou Dongmo C S Guedjeo P Azinwi Tamfuh et alldquoGeochemical and geotechnical characterization of soils de-veloped on volcanic rocks in the Bamenda Mountain(Cameroon volcanic line)rdquo International Journal of AdvancedGeosciences vol 6 no 2 pp 184ndash194 2018

[11] B Minasny and A E Hartemink ldquoPredicting soil propertiesin the tropicsrdquo Earth-Science Reviews vol 106 no 1-2pp 52ndash62 2011

[12] D Baros and A Albernaz ldquoPossible impacts of climate changeon wetlands and its biota in the Brazilian Amazonrdquo BrazilianJournal of Biology vol 74 no 4 pp 810ndash820 2014

[13] P Azinwi Tamfuh E Djoufac Woumfo E TemgouaA Boukong and D Bitom ldquoMoisture moisture-relatedproperties and agricultural management strategies of theBenue floodplain Vertisols in North Cameroonrdquo AfricanJournal of Agricultural Research vol 13 no 33 pp 1730ndash1746 2018

[14] IPCC (Intergovernmental Panel on Climate Change) ldquoCli-mate change 2013 the physical science basisrdquo in Contributionof Working Group I to the Fifth Assessment Report of theIntergovernmental Panel on Climate Change T F StockerD Qin G-K Plattner et al Eds Cambridge University PressCambridge UK 2013 httpwwwipccchreportar5wg1

[15] Ramsar Sites Information Service Annotated List of Wetlandsof International Importance Cameroon Ramsar Sites Infor-mation Service Gland Switzerland 2016 httpsrsisramsarorgfrris-searchlanguageframpf[0]regioncountry_fr_ss3ACameroon

Applied and Environmental Soil Science 13

33 Soil Water Characteristic Curves Soil moisture char-acteristic curves enabled establishing the relationship be-tween the volumetric water content and soil matric potentialof the studied soil (Figure 5) using water retention data(Table 8) e curves revealed a sigmoid shape which slopedgently from the HW to UW steepened more from UW to

AW and became gentle from gravity water to complete poresaturation e Gleysols of Mile 4 Nkwen showed the lowestwater retention curve while those of Ngomgham displayedthe highest ones (Figure 5) e soils attained full watersaturation (HW+AWC+GW+AC) at a range of 5768 ofdry soil (Mile 4 Nkwen) to 9170 of dry soil (Ngomgham)

Table 3 Moisture characteristics of the Gleysols from the Bamenda Wetlands (n 20)

S no Site HW WP FC AWR AWC RAW CW UW GW AC WHC D() () () () (mmm) (mmm) (mmm) (mmm) (mmm) () (mmm) (dmm)

1Mile 4 Nkwen

912 366 4816 1156 28267 37878 2904 244 1263 649 56534 2652 72 4152 566 1508 33127 4439 394 788 227 1493 66253 3343 82 5606 6719 1113 4181 56025 4699 293 699 2719 83619 3974

Below Foncha

1776 4842 698 2138 37164 49799 5204 362 856 2632 74327 4125 1222 5568 7258 169 38754 5193 5436 468 1088 291 77507 46 222 4762 7328 2566 31767 42567 5108 346 941 3161 63533 3757 134 4592 6941 2349 35932 48148 4601 1009 434 2774 71863 418

Mulang

1232 2214 572 3506 21583 28921 4488 2274 321 1553 43166 3389 1088 4556 6247 1691 30824 41304 4559 603 392 208 61648 3210 743 5884 7267 1383 4076 54618 5324 64 976 2919 8152 40111 158 334 7049 3709 30391 40723 5469 2129 1302 2882 60781 44412 1221 4716 6262 1546 34147 45757 4141 325 207 1914 68294 34513

Ngomgham

1535 254 6834 4294 23436 31404 4999 2759 999 2834 46871 40414 1311 5886 7534 1648 40688 54522 5523 337 1175 3186 81376 41515 221 4228 6449 2221 33792 45281 4239 011 072 2282 67583 38116 939 5242 6726 1484 42361 56764 4887 545 539 2378 84722 42417 2302 27 728 458 24456 3277 4978 2278 811 3113 48911 4318

Ntamulung978 532 7324 2004 40257 53944 5346 1026 998 2976 80513 418

19 1567 415 6192 2042 31032 41583 4625 475 277 1844 62064 40420 1721 565 7421 1771 39157 5247 5700 050 1352 3073 78314 341

Table 4 Summary statistics of the soil moisture characteristics in the Bamenda wetlands (n 20)

Parameters HW WP FC AWR AWC RAW CW UW WHC D GW AC() () () () (mmm) (mmm) () () (mmm) (dmm) () ()

Minimum 720 2214 4816 1113 21583 28921 2904 011 43166 265 072 649Maximum 2302 5886 7534 4580 42361 56764 5700 2759 84722 4 44 1352 3186Mean 1372 4480 6700 2220 33985 45540 4809 848 67970 383 746 2476SD 487 1116 709 1016 6287 8424 665 825 12573 045 408 689CV 3600 2500 1100 4600 1800 1800 1400 9700 1800 1200 5500 2800Skew 059 minus066 minus115 127 minus048 minus048 minus121 133 minus048 minus106 minus014 minus119Kurtosis minus053 minus045 110 063 minus070 minus070 216 047 minus070 081 minus140 097K-S stat 013 013 016 020 013 013 012 025 013 022 013 020HW hygroscopic water WP permanent wilting point FC field capacity AWR available water reserve AWC available water content RAW readilyavailable water CW capillary water UW unavailable water WHC water-holding capacity D weighting depth AC air content GW gravity water CVcoefficient of variation SD standard deviation K-S stat KolmogorovndashSmirnov statistics

Table 5 Correlation amongst soil physical characteristics and soil organic carbon

Soil properties Dp Db Sand Silt Clay RF SOC Siltclay ratio SOCSDp 1 mdash mdash mdash mdash mdash mdash mdashDb 02 1 mdash mdash mdash mdash mdash mdash mdashSand 038 minus012 1 mdash mdash mdash mdash mdash mdashSilt 022 minus002 minus032 1 mdash mdash mdash mdashClay minus052lowast minus011 minus063lowastlowast minus041 1 mdash mdash mdash mdashRF 011 minus02 minus025 024 minus008 1 mdash mdash mdashSOC minus049lowast minus04 minus031 minus031 069lowastlowast minus026 1 mdash mdashSiltclay ratio 046lowast 01 017 080lowastlowast minus084lowastlowast 022 minus064lowastlowast 1 mdashSOCS minus048lowast 049lowast minus036 minus040 053lowastlowast minus032 minus065lowastlowast 098lowastlowast 100lowastCorrelation is significant at the 005 level lowastlowastcorrelation is significant at the 001 level

8 Applied and Environmental Soil Science

e height of the water characteristic curves shows a meanincreasing trend such that Ngomghamgt belowFonchagtMulanggtNtamulunggtMile 4 Nkwen

4 Discussion

41 Soil Moisture Storage Capacity of Gleysols as Affected byPhysical Properties and SOC e Gleysols of the Bamendawetlands were reddish brown wet and waterlogged with

reddish yellow and blue patches in the more waterloggedareas e surface aspect of the studied Gleysols is shown inFigure 6 ese properties are common to all wetland soils[28] e massive structure and high density of these soilscan be attributed to high clay content e high clay contentin turn made the soils stick to farm tools e sandsilt ratiois an index of weathering intensity according to Sharma et al[36] All the ratio values were greater than 045 typical ofmoderate weather e siltclay ratio of the Gleysols wasgt015 indicating that the soils are relatively young or gt020portraying a high degree of weathering potential [37] eseindices agreed with values of alluvial floodplain Gleysols[13]

e plant-available water content of the BamendaGleysols was very high according to GEPPA [34] Such high

Table 6 Pearson linear correlation coefficients amongst soil moisture characteristics (n 20)

Soil properties HW WP FC AWR AWC RAW CW UW WHC DHW 100 mdash mdash mdash mdash mdash mdash mdash mdash mdashWP minus032 100 mdash mdash mdash mdash mdash mdash mdash mdashFC 036 045 100 mdash mdash mdash mdash mdash mdash mdashAWR 059lowast minus078lowastlowast 020 100 mdash mdash mdash mdash mdash mdashAWC minus036 095lowastlowast 046lowast minus073lowastlowast 100 mdash mdash mdash mdash mdashRAW minus036 095lowastlowast 046lowastlowast minus073lowastlowast 099lowastlowast 100 mdash mdash mdash mdashCW 025 037 092lowastlowast 024 038 038 100 mdash mdash mdashUW 014 minus078lowastlowast 004 088lowastlowast minus068lowastlowast minus068lowastlowast 014 100 mdash mdashWHC minus036 minus036 046lowast -073lowastlowast 100 100 038 minus068lowastlowast 100 mdashD 027 013 074lowastlowast 037 029 036 070lowastlowast 030 029 100Dp 012 054lowast 031 037 052lowast 052lowast 035 038 minus052lowast minus017Db 002 minus037 minus009 034 minus008 minus008 minus001 041 minus008 047lowastSand 004 minus057lowast minus048lowast 028 minus054lowast minus054lowast minus047lowast 033 minus054lowast 048lowastSilt 029 minus048lowast minus005 049lowast minus045 minus045 minus006 042 minus044 minus051lowastClay minus034 081lowastlowast 027 minus070lowast 081lowastlowast 081lowastlowast 019 minus066lowastlowast 081lowastlowast 022RF 015 minus001 039 029 minus010 minus010 033 026 minus010 007SOC minus035 085lowastlowast 039 -066lowast 081lowastlowast 081lowastlowast 031 minus061lowastlowast 081lowastlowast 025Siltclay ratio 044 004 minus006 minus008 007 007 minus020 minus035 007 minus014SOCS minus035 096lowastlowast 045 minus082lowastlowast 094lowastlowast 094lowastlowast 037 minus079lowastlowast 094lowastlowast 005lowastCorrelation is significant at the 005 level lowastlowastcorrelation is significant at the 001 level

Table 7 Principal component analysis generated based on factorloading (n 20)

Soil properties PC1 PC2 PC3HW minus036 048 023WP 098 minus001 011FC 042 084 028AWR minus079 059 007AWC 097 008 minus013RAW 097 008 minus013CW 036 081 029UW minus076 044 minus005WHC 097 008 -013D 020 086 minus023Dp minus061 minus011 019Db minus028 032 minus072Sand minus059 minus038 074Silt 011 minus057 051Clay 087 minus-001 minus024RF minus010 046 033SOC 089 minus001 008Total loadinga 1175 65 194 variance explained 4512 1893 968Cumulative variance explained 4512 1893 7373RF coarse fragments extraction method principal component analysisaSums of loadings PC1 PC2 and PC3 are the first second and thirdprincipal components

0

1

075

05

025

ndash025

ndash05

ndash075

ndash1ndash1 ndash075 ndash05 ndash025 0 025 05 075 1

AWR HW RF

D CWFC

AWC RAW WHC

Clay SOC WP

Silt

Sand

Dp

Db

UW

Variables (axes F1 and F2 6404)

F2 (1

893

)

F1 (4512)

Figure 4 Graphical representation of the first two principalcomponents of soil and moisture characteristics Extractionmethod principal component analysis (n 20)

Applied and Environmental Soil Science 9

values have already been reported in some wetland soils ofNorth Cameroon [13] Also comparatively lower availablewater contents have also been reported elsewhere such as11000mmm in Australia [38] 12500mmm in Sudan [39]and 23000mmm in India [40] e difference is oftenattributed to soil texture climate and topographic positions[9 10]

e WHC values for soils from 95 of the samplingpoints of the Bamenda Gleysols were very high(gt600mmm) and comparable with values of somewetland soil in North Cameroon [13] us Gleysolsdominated by silt and sand have low WHC values while

clay-rich ones show high WHC values [38] e highvalues of RAW observed in most of the studied soils are afunction of the soil texture and the organic mattercontents of the Gleysols

e air capacity of the studied Gleysols was highcompared to the optimum root aeration value of 1000 andthe critical value of 500 required for optimum plantperformance [40] Such high air contents indicate high freewater potential So most of the water that infiltrates intopores is retained in the profiles and induces soil imper-meability surface ponding poor aeration and floods in therainy season [41]

Mile 4 Nkwen

Below Foncha

Mulang

Ngomgham

Ntamulung

Oven-dry Moist Wet

Gravity water

Gravity water

Soil water potential (kPa log scale)

Wat

er co

nten

t (

wat

er1

00g

of d

ry so

il)

Capillary water

Plant-available waterUnavailable water

Hygroscopicwater HC WP FC

0ndash1ndash10ndash100ndash1000ndash10000ndash1000000

10

20

30

40

50

60

70

80

90

Figure 5 Mean moisture retention curve of the Gleysols from different studied sites in the Bamenda wetlands HC hygroscopic coefficientWP moisture content at permanent wilting point FC moisture content at field capacity

Table 8 Cumulative soil moisture contents (in of dry soil) used to model the water characteristic curves of the Gleysols in the Bamendawetlands

Properties HW UW UW+AWR UW+AWR+GW UW+AWR+GW+ACMile 4 Nkwen (n 3) 817 2159 2718 4148 5768Below Foncha (n 4) 1640 2186 4372 5202 8072Mulang (n 5) 1173 2367 4939 5579 7849Ngomgham (n 5) 166 2846 5691 6411 9170Ntamulung (n 3) 1422 1939 3878 4753 7384Mean (n 20) 1372 2300 4460 5220 7650HW hygroscopic water content UW unavailable water content AWR available water reserve CW capillary water content GW gravity water content ACair content n number of samples

10 Applied and Environmental Soil Science

e soil moisture characteristics increased considerablyfrom upstream at Mile 4 Nkwen to downstream atNgomgham Mulang below Foncha and Ntamulung ismight be related to transport and deposition of fine earthmaterial from upstream to downstream and to the geo-morphological configuration of the studied site or even tospecific soil characteristics like the mineralogical composi-tion of the clayey fraction Also several soil internal factorsmay be responsible for the variation in the soil moistureretention curve per site such as nonuniformity of porescontact angle difference and entrapped air in pore space[42]

e capillary water of the wetland soils was high as thiswater fraction is held to soil particles by weak surface tensionforces of soil particles and is thus available to plants Duringconditions of water stress (particularly during the dry season)capillarity plays a vital role in maintaining crop performancee soil water loss is faster at the surface than at depth causinga higher water tension at the surface than at depth [43 44] Itcauses a higher water tension at the surface than at depth andthis creates a water capillary current which moves from baseto surface and hence water rises to the surface to be availableto plants [45 46]e FC andWP are primarily influenced byirregular pore geometry and discontinuity and variations intexture and mineralogy [47ndash50]

In this study clay content of the soils correlated best withthe moisture characteristics more than any other propertye clay and SOC contents probably linked together asrevealed by their significant positive correlation favor theoccurrence of micropores and menisci that generate capil-lary forcesus they increase the specific surface area of thesoil matrix and consequently water adsorption [48] Al-though siltclay ratio displays no significant correlation withsoil moisture characteristics it negatively strongly correlateswith SOC e size and structure of clay particles were moresuitable for association with SOM molecules than the sizeand the structure of bigger soil particles [49] e clay andSOC contents are indispensable in the water and nutrientretention for plants based on their high specific surface area[50] Sand and coarse fragments contents tend to increasesoil particle density thereby increasing macroporosity and

reducing microporosity hence lowering the soil capacity toretain water [51] us low correlation coefficients betweensand and coarse fragments contents and WHC are docu-mented [52 53] meanwhile the negative correlation be-tween SOC and silt content is not in line with some results[44]

e statistical analysis of the studied soil propertiesfollowed a log-normal distribution as revealed by the co-efficient of kurtosis and skewness indicating possible an-thropogenic disturbances Under natural grasslands manysoil variables tend to conform to normal distribution due tothe homogenization effect of biotic factors [54] Followingirrigation or rainfall that saturates the soil making its watercontent higher than FC there should normally be adownward movement of water by gravity action Infiltrationis related to hydraulic conductivity that leads to decrease insoil moisture content as infiltration leads to soil water loss

42 Implications of theGleysolsCharacteristics onAgriculturalManagement Strategies In the Bamenda wetlands waterlosses often attain WP in the dry season making plant-available water contents low is condition of water stresshas been reported to cause drastic decrease in yields inwetlands [55] erefore for irrigation the ldquoplant readilyavailable waterrdquo constitutes the ideal operating range of soilmoisture for irrigation management [29 56] us irriga-tion scheduling should involve the replacement of depletedwater not higher than the FC to avoid waterlogging in thesesoils as drainage andor deep percolation is poor But sincethe soils are flooded in the rainy season it implies that theirwater content is above the FC and thus necessitating thedrainage of excess water during farming in the rainy seasone soil water characteristic curves become an indispensableto design irrigation schedules especially in the dry seasonduring moisture deficiency or to drain excess water in therainy season [57ndash59]

To achieve high yields without creating excess drainageit is necessary to know the crop readily available to becultivated After readily available water has been used plantroots cannot easily extract water and nutrients from the soil

Table 9 List of Ramsar sites in Cameroon [15]

SN Site Ramsar

identifierDesignation

date Region Geographic coordinates Altitude(m)

Surface area(km2)

1 Waza-Logone floodplain 1609 26052006 ExtremeNorth

11deg 37prime 59primeNorth14deg 37prime 01prime East 300 6000

2 Barombi-Mbo Lake 1643 810rsquo2006 South west 4deg 40prime 01primeNorth9deg 22prime 59primeEast 301ndash400 415

3 Cameroon section of theSangha River 1739 2022008 East 1deg 49prime 59primeNorth

16deg 01prime 59primeEast 350ndash700 62

4 Cameroon section of LakeChad 1903 2022010 Extreme

North12deg 46prime 01primeNorth14deg18prime 00primeEast 160ndash280 125

5 Rio Del Rey Estuary 1908 20052010 South West 4deg 37prime 01primeNorth8deg 43prime 01prime East 5 1650

6 Cameroon section of theNtem River 2067 5062012 South 2deg 22prime 44primeNorth

10deg 33prime14primeEast 400ndash526 39848

7 Ebogo Humid Zone 2028 605 2012 Centre 3deg 23prime10primeNorth11deg 29prime 20primeEast 630ndash670 3097

Applied and Environmental Soil Science 11

and this is the time to irrigate or refill pointe drier the soilis the more water it needs to return to field capacityus inirrigation FC and refill point are critical values for thecorrect use of many of the soil water monitoring

e high clay content of the Gleysols in the Bamendawetlands makes tillage and weed control in these areasdifficult due to the presence of water and sticky nature ofsoils to farm tools e high bulk density of the Gleysols isvery high (16 gmiddotcmminus3) compared to the optimum value(133 gmiddotcmminus3) for root penetration but also close to the upperlimit (175 gmiddotcmminus3) for root growth and is therefore a lim-iting factor to agriculture [60] High bulk density impliesthat the soils are not well aerated as most of the pores aresaturated with water during wet conditions

e highly significant correlation between clay and or-ganic matter contents reveals that both are linked together toform organo-mineral complexes and thus the SOC is beingprotected by soil matrix ese two soil colloids play a vital

role in the retention of water and nutrients for crop needs asrevealed by their high correlation with most of the moisturecharacteristicse high SOC implies a high cation exchangecapacity (CEC) e overall CEC of SOC and clay contentsfavors the retention and availability of nutrients to maintaincrop production in those Gleysols [60ndash62]

Particle size distribution also conditions chemical nu-trient supply [63] Most of the studied Gleysols samples haveclay plus silt content greater than 35 this indicates poornutrient assimilation by plants A correlation has also beenestablished between particle size distribution and yields [63]e (silt + sand)-to-total earth ratios of the Gleysols werevery high (gtgt35) relative to the ratio range of 15 to 35necessary for optimum yields and indicate potentially pooryields for a majority of tropical crops [63]

e SOCS of the Bamenda wetlands Gleysols is very high(gt200Mgmiddothaminus1) as such wetlands especially floodplains areoften very productive [4] Such ecosystems have the ability of

(a) (b)

(c) (d)

(e) (f )

Figure 6 Photographs of wetland ecosystems in Nkwen (Bamenda) (a) Wetland with grassed vegetation (b) water retained in furrows ofraised ridges (c d) channeling of water into farmlands for irrigation (e f ) healthy maize crops cultivated in the wetlands of Bamenda

12 Applied and Environmental Soil Science

sequestering and storing carbon through photosynthesis andorganic matter accumulation in soils and plant biomassthereby offering the opportunity for regaining lost pro-ductivity especially under agricultural systems e prop-erties of these studied soils could be similar to those of someRamsar sites in Cameroon although with some site specificfeatures Table 9 shows different Ramsar sites in Cameroon

5 Conclusion

In Bamenda City (Northwest Cameroon) population in-crease has led to considerable lawless occupation of wetlandsespecially as these areas are very fertile and support year-round agriculture Land use is often done without necessarytechnical know-how of sustainable land managementtechniques is work was focused on the determination ofmoisture characteristics of Gleysols in the Bamenda wet-lands and to establish a link between them and selected soilcharacteristics affecting crop production

e major findings revealed that the Gleysols showedvery high organic carbon contents and very high soil organiccarbon stocks implying a high level of carbon sequestrationMajor constraints of the soils to farming were clay plus siltcontents massive structure and waterlogging e moistureproperties revealed very high water-holding capacity andvery high plant-available water e particle density andcoarse fragments and sand contents correlated negativelywith the soil moisture retention characteristics and could bereducing the soilrsquos water-holding capacity e soil moisturecharacteristics curves were sigmoid-shaped and their heightsdecreased from upstream to downstream probably por-traying increase of finer material with fluvial transportdistant

e present work might have been limited in terms ofthe inadequate number of samples studied Further re-search is necessary on these wetland soils of the northwestregion of Cameroon to evaluate their potential risk ofdegradation based on a higher number of samples Alsothe results presented in this work might have been biasedbased on the fact that the tests were conducted solely inthe laboratory In the future measurements of waterstorage capacity of these soils should be done directly inthe field using more accurate methods such as electricalresistance and tensiometric and heat-diffusion methodsIrrigation schedules on this these soils should involve thereplacement of depleted water with water amounts notexceeding the FC to avoid waterlogging in these soils asdrainage andor deep percolation is poor Adapted cropslike lowland rice could also be introduced to extend thesurfaces of rice cultivation in the zone

Data Availability

Data can be made available on request

Conflicts of Interest

e authors declare no conflicts of interest

References

[1] W J Rawls T J Gish and D L Brakensiek ldquoEstimating soilwater retention from soil physical properties and character-isticsrdquoAdvances in Soil Science vol 16 pp 213ndash234 Springer-Verlag New York Inc NY USA 1991

[2] E Kellner and S Halldin ldquoWater budget and surface-layerwater storage in a Sphagnum bog in central Swedenrdquo Hy-drological Processes vol 16 no 1 pp 87ndash103 2002

[3] R M Khalid and H A K Ahmed ldquoNature of soil-watercharacteristics curves (SWCC) for soils from Anbar Gover-noraterdquo Anbar Journal of Engineering Sciences vol 3 no 1pp 61ndash80 2010

[4] e Ramsar Convention on Wetlands ldquoClimate Change andWetlands Resolution X24rdquo in Proceedings of the 10thMeeting of the Conference of the Parties to the Convention onWetlands Changwon Republic of Korea October 2008httpswwwramsarorgdocumentresolution-x24-climate-change-and-wetlands

[5] J Vopravil P Formanek and T Khel ldquoComparison of thephysical properties of soils belonging to different referencesoil groupsrdquo Soil andWater Research vol 16 pp 29ndash38 2021

[6] USDA Soil Survey Manual USDA Washington D C USA2017

[7] S R Carpenter W A Brock and P Hanson ldquoResilientmanagement comments onrdquo Ecological and Social Dynamics inSimple Models of EcosystemManagement Conservation EcologyResilience Alliance vol 3 no 2 Wisconsin USA 1999

[8] K E Saxton and W J Rawls ldquoSoil water characteristic es-timates by texture and organic matter for hydrologic solu-tionsrdquo Soil Science Society of America Journal vol 70 no 5pp 1569ndash1578 2006

[9] P A Tamfuh A H Chotangui A H Chotangui et al ldquoLandcharacteristics and agricultural suitability status along a top-osequence in Santa Bamenda Highlands Cameroonrdquo Journalof Atmospheric amp Earth Science vol 4 no 1 pp 1ndash9 2020

[10] A Kagou Dongmo C S Guedjeo P Azinwi Tamfuh et alldquoGeochemical and geotechnical characterization of soils de-veloped on volcanic rocks in the Bamenda Mountain(Cameroon volcanic line)rdquo International Journal of AdvancedGeosciences vol 6 no 2 pp 184ndash194 2018

[11] B Minasny and A E Hartemink ldquoPredicting soil propertiesin the tropicsrdquo Earth-Science Reviews vol 106 no 1-2pp 52ndash62 2011

[12] D Baros and A Albernaz ldquoPossible impacts of climate changeon wetlands and its biota in the Brazilian Amazonrdquo BrazilianJournal of Biology vol 74 no 4 pp 810ndash820 2014

[13] P Azinwi Tamfuh E Djoufac Woumfo E TemgouaA Boukong and D Bitom ldquoMoisture moisture-relatedproperties and agricultural management strategies of theBenue floodplain Vertisols in North Cameroonrdquo AfricanJournal of Agricultural Research vol 13 no 33 pp 1730ndash1746 2018

[14] IPCC (Intergovernmental Panel on Climate Change) ldquoCli-mate change 2013 the physical science basisrdquo in Contributionof Working Group I to the Fifth Assessment Report of theIntergovernmental Panel on Climate Change T F StockerD Qin G-K Plattner et al Eds Cambridge University PressCambridge UK 2013 httpwwwipccchreportar5wg1

[15] Ramsar Sites Information Service Annotated List of Wetlandsof International Importance Cameroon Ramsar Sites Infor-mation Service Gland Switzerland 2016 httpsrsisramsarorgfrris-searchlanguageframpf[0]regioncountry_fr_ss3ACameroon

Applied and Environmental Soil Science 13

e height of the water characteristic curves shows a meanincreasing trend such that Ngomghamgt belowFonchagtMulanggtNtamulunggtMile 4 Nkwen

4 Discussion

41 Soil Moisture Storage Capacity of Gleysols as Affected byPhysical Properties and SOC e Gleysols of the Bamendawetlands were reddish brown wet and waterlogged with

reddish yellow and blue patches in the more waterloggedareas e surface aspect of the studied Gleysols is shown inFigure 6 ese properties are common to all wetland soils[28] e massive structure and high density of these soilscan be attributed to high clay content e high clay contentin turn made the soils stick to farm tools e sandsilt ratiois an index of weathering intensity according to Sharma et al[36] All the ratio values were greater than 045 typical ofmoderate weather e siltclay ratio of the Gleysols wasgt015 indicating that the soils are relatively young or gt020portraying a high degree of weathering potential [37] eseindices agreed with values of alluvial floodplain Gleysols[13]

e plant-available water content of the BamendaGleysols was very high according to GEPPA [34] Such high

Table 6 Pearson linear correlation coefficients amongst soil moisture characteristics (n 20)

Soil properties HW WP FC AWR AWC RAW CW UW WHC DHW 100 mdash mdash mdash mdash mdash mdash mdash mdash mdashWP minus032 100 mdash mdash mdash mdash mdash mdash mdash mdashFC 036 045 100 mdash mdash mdash mdash mdash mdash mdashAWR 059lowast minus078lowastlowast 020 100 mdash mdash mdash mdash mdash mdashAWC minus036 095lowastlowast 046lowast minus073lowastlowast 100 mdash mdash mdash mdash mdashRAW minus036 095lowastlowast 046lowastlowast minus073lowastlowast 099lowastlowast 100 mdash mdash mdash mdashCW 025 037 092lowastlowast 024 038 038 100 mdash mdash mdashUW 014 minus078lowastlowast 004 088lowastlowast minus068lowastlowast minus068lowastlowast 014 100 mdash mdashWHC minus036 minus036 046lowast -073lowastlowast 100 100 038 minus068lowastlowast 100 mdashD 027 013 074lowastlowast 037 029 036 070lowastlowast 030 029 100Dp 012 054lowast 031 037 052lowast 052lowast 035 038 minus052lowast minus017Db 002 minus037 minus009 034 minus008 minus008 minus001 041 minus008 047lowastSand 004 minus057lowast minus048lowast 028 minus054lowast minus054lowast minus047lowast 033 minus054lowast 048lowastSilt 029 minus048lowast minus005 049lowast minus045 minus045 minus006 042 minus044 minus051lowastClay minus034 081lowastlowast 027 minus070lowast 081lowastlowast 081lowastlowast 019 minus066lowastlowast 081lowastlowast 022RF 015 minus001 039 029 minus010 minus010 033 026 minus010 007SOC minus035 085lowastlowast 039 -066lowast 081lowastlowast 081lowastlowast 031 minus061lowastlowast 081lowastlowast 025Siltclay ratio 044 004 minus006 minus008 007 007 minus020 minus035 007 minus014SOCS minus035 096lowastlowast 045 minus082lowastlowast 094lowastlowast 094lowastlowast 037 minus079lowastlowast 094lowastlowast 005lowastCorrelation is significant at the 005 level lowastlowastcorrelation is significant at the 001 level

Table 7 Principal component analysis generated based on factorloading (n 20)

Soil properties PC1 PC2 PC3HW minus036 048 023WP 098 minus001 011FC 042 084 028AWR minus079 059 007AWC 097 008 minus013RAW 097 008 minus013CW 036 081 029UW minus076 044 minus005WHC 097 008 -013D 020 086 minus023Dp minus061 minus011 019Db minus028 032 minus072Sand minus059 minus038 074Silt 011 minus057 051Clay 087 minus-001 minus024RF minus010 046 033SOC 089 minus001 008Total loadinga 1175 65 194 variance explained 4512 1893 968Cumulative variance explained 4512 1893 7373RF coarse fragments extraction method principal component analysisaSums of loadings PC1 PC2 and PC3 are the first second and thirdprincipal components

0

1

075

05

025

ndash025

ndash05

ndash075

ndash1ndash1 ndash075 ndash05 ndash025 0 025 05 075 1

AWR HW RF

D CWFC

AWC RAW WHC

Clay SOC WP

Silt

Sand

Dp

Db

UW

Variables (axes F1 and F2 6404)

F2 (1

893

)

F1 (4512)

Figure 4 Graphical representation of the first two principalcomponents of soil and moisture characteristics Extractionmethod principal component analysis (n 20)

Applied and Environmental Soil Science 9

values have already been reported in some wetland soils ofNorth Cameroon [13] Also comparatively lower availablewater contents have also been reported elsewhere such as11000mmm in Australia [38] 12500mmm in Sudan [39]and 23000mmm in India [40] e difference is oftenattributed to soil texture climate and topographic positions[9 10]

e WHC values for soils from 95 of the samplingpoints of the Bamenda Gleysols were very high(gt600mmm) and comparable with values of somewetland soil in North Cameroon [13] us Gleysolsdominated by silt and sand have low WHC values while

clay-rich ones show high WHC values [38] e highvalues of RAW observed in most of the studied soils are afunction of the soil texture and the organic mattercontents of the Gleysols

e air capacity of the studied Gleysols was highcompared to the optimum root aeration value of 1000 andthe critical value of 500 required for optimum plantperformance [40] Such high air contents indicate high freewater potential So most of the water that infiltrates intopores is retained in the profiles and induces soil imper-meability surface ponding poor aeration and floods in therainy season [41]

Mile 4 Nkwen

Below Foncha

Mulang

Ngomgham

Ntamulung

Oven-dry Moist Wet

Gravity water

Gravity water

Soil water potential (kPa log scale)

Wat

er co

nten

t (

wat

er1

00g

of d

ry so

il)

Capillary water

Plant-available waterUnavailable water

Hygroscopicwater HC WP FC

0ndash1ndash10ndash100ndash1000ndash10000ndash1000000

10

20

30

40

50

60

70

80

90

Figure 5 Mean moisture retention curve of the Gleysols from different studied sites in the Bamenda wetlands HC hygroscopic coefficientWP moisture content at permanent wilting point FC moisture content at field capacity

Table 8 Cumulative soil moisture contents (in of dry soil) used to model the water characteristic curves of the Gleysols in the Bamendawetlands

Properties HW UW UW+AWR UW+AWR+GW UW+AWR+GW+ACMile 4 Nkwen (n 3) 817 2159 2718 4148 5768Below Foncha (n 4) 1640 2186 4372 5202 8072Mulang (n 5) 1173 2367 4939 5579 7849Ngomgham (n 5) 166 2846 5691 6411 9170Ntamulung (n 3) 1422 1939 3878 4753 7384Mean (n 20) 1372 2300 4460 5220 7650HW hygroscopic water content UW unavailable water content AWR available water reserve CW capillary water content GW gravity water content ACair content n number of samples

10 Applied and Environmental Soil Science

e soil moisture characteristics increased considerablyfrom upstream at Mile 4 Nkwen to downstream atNgomgham Mulang below Foncha and Ntamulung ismight be related to transport and deposition of fine earthmaterial from upstream to downstream and to the geo-morphological configuration of the studied site or even tospecific soil characteristics like the mineralogical composi-tion of the clayey fraction Also several soil internal factorsmay be responsible for the variation in the soil moistureretention curve per site such as nonuniformity of porescontact angle difference and entrapped air in pore space[42]

e capillary water of the wetland soils was high as thiswater fraction is held to soil particles by weak surface tensionforces of soil particles and is thus available to plants Duringconditions of water stress (particularly during the dry season)capillarity plays a vital role in maintaining crop performancee soil water loss is faster at the surface than at depth causinga higher water tension at the surface than at depth [43 44] Itcauses a higher water tension at the surface than at depth andthis creates a water capillary current which moves from baseto surface and hence water rises to the surface to be availableto plants [45 46]e FC andWP are primarily influenced byirregular pore geometry and discontinuity and variations intexture and mineralogy [47ndash50]

In this study clay content of the soils correlated best withthe moisture characteristics more than any other propertye clay and SOC contents probably linked together asrevealed by their significant positive correlation favor theoccurrence of micropores and menisci that generate capil-lary forcesus they increase the specific surface area of thesoil matrix and consequently water adsorption [48] Al-though siltclay ratio displays no significant correlation withsoil moisture characteristics it negatively strongly correlateswith SOC e size and structure of clay particles were moresuitable for association with SOM molecules than the sizeand the structure of bigger soil particles [49] e clay andSOC contents are indispensable in the water and nutrientretention for plants based on their high specific surface area[50] Sand and coarse fragments contents tend to increasesoil particle density thereby increasing macroporosity and

reducing microporosity hence lowering the soil capacity toretain water [51] us low correlation coefficients betweensand and coarse fragments contents and WHC are docu-mented [52 53] meanwhile the negative correlation be-tween SOC and silt content is not in line with some results[44]

e statistical analysis of the studied soil propertiesfollowed a log-normal distribution as revealed by the co-efficient of kurtosis and skewness indicating possible an-thropogenic disturbances Under natural grasslands manysoil variables tend to conform to normal distribution due tothe homogenization effect of biotic factors [54] Followingirrigation or rainfall that saturates the soil making its watercontent higher than FC there should normally be adownward movement of water by gravity action Infiltrationis related to hydraulic conductivity that leads to decrease insoil moisture content as infiltration leads to soil water loss

42 Implications of theGleysolsCharacteristics onAgriculturalManagement Strategies In the Bamenda wetlands waterlosses often attain WP in the dry season making plant-available water contents low is condition of water stresshas been reported to cause drastic decrease in yields inwetlands [55] erefore for irrigation the ldquoplant readilyavailable waterrdquo constitutes the ideal operating range of soilmoisture for irrigation management [29 56] us irriga-tion scheduling should involve the replacement of depletedwater not higher than the FC to avoid waterlogging in thesesoils as drainage andor deep percolation is poor But sincethe soils are flooded in the rainy season it implies that theirwater content is above the FC and thus necessitating thedrainage of excess water during farming in the rainy seasone soil water characteristic curves become an indispensableto design irrigation schedules especially in the dry seasonduring moisture deficiency or to drain excess water in therainy season [57ndash59]

To achieve high yields without creating excess drainageit is necessary to know the crop readily available to becultivated After readily available water has been used plantroots cannot easily extract water and nutrients from the soil

Table 9 List of Ramsar sites in Cameroon [15]

SN Site Ramsar

identifierDesignation

date Region Geographic coordinates Altitude(m)

Surface area(km2)

1 Waza-Logone floodplain 1609 26052006 ExtremeNorth

11deg 37prime 59primeNorth14deg 37prime 01prime East 300 6000

2 Barombi-Mbo Lake 1643 810rsquo2006 South west 4deg 40prime 01primeNorth9deg 22prime 59primeEast 301ndash400 415

3 Cameroon section of theSangha River 1739 2022008 East 1deg 49prime 59primeNorth

16deg 01prime 59primeEast 350ndash700 62

4 Cameroon section of LakeChad 1903 2022010 Extreme

North12deg 46prime 01primeNorth14deg18prime 00primeEast 160ndash280 125

5 Rio Del Rey Estuary 1908 20052010 South West 4deg 37prime 01primeNorth8deg 43prime 01prime East 5 1650

6 Cameroon section of theNtem River 2067 5062012 South 2deg 22prime 44primeNorth

10deg 33prime14primeEast 400ndash526 39848

7 Ebogo Humid Zone 2028 605 2012 Centre 3deg 23prime10primeNorth11deg 29prime 20primeEast 630ndash670 3097

Applied and Environmental Soil Science 11

and this is the time to irrigate or refill pointe drier the soilis the more water it needs to return to field capacityus inirrigation FC and refill point are critical values for thecorrect use of many of the soil water monitoring

e high clay content of the Gleysols in the Bamendawetlands makes tillage and weed control in these areasdifficult due to the presence of water and sticky nature ofsoils to farm tools e high bulk density of the Gleysols isvery high (16 gmiddotcmminus3) compared to the optimum value(133 gmiddotcmminus3) for root penetration but also close to the upperlimit (175 gmiddotcmminus3) for root growth and is therefore a lim-iting factor to agriculture [60] High bulk density impliesthat the soils are not well aerated as most of the pores aresaturated with water during wet conditions

e highly significant correlation between clay and or-ganic matter contents reveals that both are linked together toform organo-mineral complexes and thus the SOC is beingprotected by soil matrix ese two soil colloids play a vital

role in the retention of water and nutrients for crop needs asrevealed by their high correlation with most of the moisturecharacteristicse high SOC implies a high cation exchangecapacity (CEC) e overall CEC of SOC and clay contentsfavors the retention and availability of nutrients to maintaincrop production in those Gleysols [60ndash62]

Particle size distribution also conditions chemical nu-trient supply [63] Most of the studied Gleysols samples haveclay plus silt content greater than 35 this indicates poornutrient assimilation by plants A correlation has also beenestablished between particle size distribution and yields [63]e (silt + sand)-to-total earth ratios of the Gleysols werevery high (gtgt35) relative to the ratio range of 15 to 35necessary for optimum yields and indicate potentially pooryields for a majority of tropical crops [63]

e SOCS of the Bamenda wetlands Gleysols is very high(gt200Mgmiddothaminus1) as such wetlands especially floodplains areoften very productive [4] Such ecosystems have the ability of

(a) (b)

(c) (d)

(e) (f )

Figure 6 Photographs of wetland ecosystems in Nkwen (Bamenda) (a) Wetland with grassed vegetation (b) water retained in furrows ofraised ridges (c d) channeling of water into farmlands for irrigation (e f ) healthy maize crops cultivated in the wetlands of Bamenda

12 Applied and Environmental Soil Science

sequestering and storing carbon through photosynthesis andorganic matter accumulation in soils and plant biomassthereby offering the opportunity for regaining lost pro-ductivity especially under agricultural systems e prop-erties of these studied soils could be similar to those of someRamsar sites in Cameroon although with some site specificfeatures Table 9 shows different Ramsar sites in Cameroon

5 Conclusion

In Bamenda City (Northwest Cameroon) population in-crease has led to considerable lawless occupation of wetlandsespecially as these areas are very fertile and support year-round agriculture Land use is often done without necessarytechnical know-how of sustainable land managementtechniques is work was focused on the determination ofmoisture characteristics of Gleysols in the Bamenda wet-lands and to establish a link between them and selected soilcharacteristics affecting crop production

e major findings revealed that the Gleysols showedvery high organic carbon contents and very high soil organiccarbon stocks implying a high level of carbon sequestrationMajor constraints of the soils to farming were clay plus siltcontents massive structure and waterlogging e moistureproperties revealed very high water-holding capacity andvery high plant-available water e particle density andcoarse fragments and sand contents correlated negativelywith the soil moisture retention characteristics and could bereducing the soilrsquos water-holding capacity e soil moisturecharacteristics curves were sigmoid-shaped and their heightsdecreased from upstream to downstream probably por-traying increase of finer material with fluvial transportdistant

e present work might have been limited in terms ofthe inadequate number of samples studied Further re-search is necessary on these wetland soils of the northwestregion of Cameroon to evaluate their potential risk ofdegradation based on a higher number of samples Alsothe results presented in this work might have been biasedbased on the fact that the tests were conducted solely inthe laboratory In the future measurements of waterstorage capacity of these soils should be done directly inthe field using more accurate methods such as electricalresistance and tensiometric and heat-diffusion methodsIrrigation schedules on this these soils should involve thereplacement of depleted water with water amounts notexceeding the FC to avoid waterlogging in these soils asdrainage andor deep percolation is poor Adapted cropslike lowland rice could also be introduced to extend thesurfaces of rice cultivation in the zone

Data Availability

Data can be made available on request

Conflicts of Interest

e authors declare no conflicts of interest

References

[1] W J Rawls T J Gish and D L Brakensiek ldquoEstimating soilwater retention from soil physical properties and character-isticsrdquoAdvances in Soil Science vol 16 pp 213ndash234 Springer-Verlag New York Inc NY USA 1991

[2] E Kellner and S Halldin ldquoWater budget and surface-layerwater storage in a Sphagnum bog in central Swedenrdquo Hy-drological Processes vol 16 no 1 pp 87ndash103 2002

[3] R M Khalid and H A K Ahmed ldquoNature of soil-watercharacteristics curves (SWCC) for soils from Anbar Gover-noraterdquo Anbar Journal of Engineering Sciences vol 3 no 1pp 61ndash80 2010

[4] e Ramsar Convention on Wetlands ldquoClimate Change andWetlands Resolution X24rdquo in Proceedings of the 10thMeeting of the Conference of the Parties to the Convention onWetlands Changwon Republic of Korea October 2008httpswwwramsarorgdocumentresolution-x24-climate-change-and-wetlands

[5] J Vopravil P Formanek and T Khel ldquoComparison of thephysical properties of soils belonging to different referencesoil groupsrdquo Soil andWater Research vol 16 pp 29ndash38 2021

[6] USDA Soil Survey Manual USDA Washington D C USA2017

[7] S R Carpenter W A Brock and P Hanson ldquoResilientmanagement comments onrdquo Ecological and Social Dynamics inSimple Models of EcosystemManagement Conservation EcologyResilience Alliance vol 3 no 2 Wisconsin USA 1999

[8] K E Saxton and W J Rawls ldquoSoil water characteristic es-timates by texture and organic matter for hydrologic solu-tionsrdquo Soil Science Society of America Journal vol 70 no 5pp 1569ndash1578 2006

[9] P A Tamfuh A H Chotangui A H Chotangui et al ldquoLandcharacteristics and agricultural suitability status along a top-osequence in Santa Bamenda Highlands Cameroonrdquo Journalof Atmospheric amp Earth Science vol 4 no 1 pp 1ndash9 2020

[10] A Kagou Dongmo C S Guedjeo P Azinwi Tamfuh et alldquoGeochemical and geotechnical characterization of soils de-veloped on volcanic rocks in the Bamenda Mountain(Cameroon volcanic line)rdquo International Journal of AdvancedGeosciences vol 6 no 2 pp 184ndash194 2018

[11] B Minasny and A E Hartemink ldquoPredicting soil propertiesin the tropicsrdquo Earth-Science Reviews vol 106 no 1-2pp 52ndash62 2011

[12] D Baros and A Albernaz ldquoPossible impacts of climate changeon wetlands and its biota in the Brazilian Amazonrdquo BrazilianJournal of Biology vol 74 no 4 pp 810ndash820 2014

[13] P Azinwi Tamfuh E Djoufac Woumfo E TemgouaA Boukong and D Bitom ldquoMoisture moisture-relatedproperties and agricultural management strategies of theBenue floodplain Vertisols in North Cameroonrdquo AfricanJournal of Agricultural Research vol 13 no 33 pp 1730ndash1746 2018

[14] IPCC (Intergovernmental Panel on Climate Change) ldquoCli-mate change 2013 the physical science basisrdquo in Contributionof Working Group I to the Fifth Assessment Report of theIntergovernmental Panel on Climate Change T F StockerD Qin G-K Plattner et al Eds Cambridge University PressCambridge UK 2013 httpwwwipccchreportar5wg1

[15] Ramsar Sites Information Service Annotated List of Wetlandsof International Importance Cameroon Ramsar Sites Infor-mation Service Gland Switzerland 2016 httpsrsisramsarorgfrris-searchlanguageframpf[0]regioncountry_fr_ss3ACameroon

Applied and Environmental Soil Science 13

values have already been reported in some wetland soils ofNorth Cameroon [13] Also comparatively lower availablewater contents have also been reported elsewhere such as11000mmm in Australia [38] 12500mmm in Sudan [39]and 23000mmm in India [40] e difference is oftenattributed to soil texture climate and topographic positions[9 10]

e WHC values for soils from 95 of the samplingpoints of the Bamenda Gleysols were very high(gt600mmm) and comparable with values of somewetland soil in North Cameroon [13] us Gleysolsdominated by silt and sand have low WHC values while

clay-rich ones show high WHC values [38] e highvalues of RAW observed in most of the studied soils are afunction of the soil texture and the organic mattercontents of the Gleysols

e air capacity of the studied Gleysols was highcompared to the optimum root aeration value of 1000 andthe critical value of 500 required for optimum plantperformance [40] Such high air contents indicate high freewater potential So most of the water that infiltrates intopores is retained in the profiles and induces soil imper-meability surface ponding poor aeration and floods in therainy season [41]

Mile 4 Nkwen

Below Foncha

Mulang

Ngomgham

Ntamulung

Oven-dry Moist Wet

Gravity water

Gravity water

Soil water potential (kPa log scale)

Wat

er co

nten

t (

wat

er1

00g

of d

ry so

il)

Capillary water

Plant-available waterUnavailable water

Hygroscopicwater HC WP FC

0ndash1ndash10ndash100ndash1000ndash10000ndash1000000

10

20

30

40

50

60

70

80

90

Figure 5 Mean moisture retention curve of the Gleysols from different studied sites in the Bamenda wetlands HC hygroscopic coefficientWP moisture content at permanent wilting point FC moisture content at field capacity

Table 8 Cumulative soil moisture contents (in of dry soil) used to model the water characteristic curves of the Gleysols in the Bamendawetlands

Properties HW UW UW+AWR UW+AWR+GW UW+AWR+GW+ACMile 4 Nkwen (n 3) 817 2159 2718 4148 5768Below Foncha (n 4) 1640 2186 4372 5202 8072Mulang (n 5) 1173 2367 4939 5579 7849Ngomgham (n 5) 166 2846 5691 6411 9170Ntamulung (n 3) 1422 1939 3878 4753 7384Mean (n 20) 1372 2300 4460 5220 7650HW hygroscopic water content UW unavailable water content AWR available water reserve CW capillary water content GW gravity water content ACair content n number of samples

10 Applied and Environmental Soil Science

e soil moisture characteristics increased considerablyfrom upstream at Mile 4 Nkwen to downstream atNgomgham Mulang below Foncha and Ntamulung ismight be related to transport and deposition of fine earthmaterial from upstream to downstream and to the geo-morphological configuration of the studied site or even tospecific soil characteristics like the mineralogical composi-tion of the clayey fraction Also several soil internal factorsmay be responsible for the variation in the soil moistureretention curve per site such as nonuniformity of porescontact angle difference and entrapped air in pore space[42]

e capillary water of the wetland soils was high as thiswater fraction is held to soil particles by weak surface tensionforces of soil particles and is thus available to plants Duringconditions of water stress (particularly during the dry season)capillarity plays a vital role in maintaining crop performancee soil water loss is faster at the surface than at depth causinga higher water tension at the surface than at depth [43 44] Itcauses a higher water tension at the surface than at depth andthis creates a water capillary current which moves from baseto surface and hence water rises to the surface to be availableto plants [45 46]e FC andWP are primarily influenced byirregular pore geometry and discontinuity and variations intexture and mineralogy [47ndash50]

In this study clay content of the soils correlated best withthe moisture characteristics more than any other propertye clay and SOC contents probably linked together asrevealed by their significant positive correlation favor theoccurrence of micropores and menisci that generate capil-lary forcesus they increase the specific surface area of thesoil matrix and consequently water adsorption [48] Al-though siltclay ratio displays no significant correlation withsoil moisture characteristics it negatively strongly correlateswith SOC e size and structure of clay particles were moresuitable for association with SOM molecules than the sizeand the structure of bigger soil particles [49] e clay andSOC contents are indispensable in the water and nutrientretention for plants based on their high specific surface area[50] Sand and coarse fragments contents tend to increasesoil particle density thereby increasing macroporosity and

reducing microporosity hence lowering the soil capacity toretain water [51] us low correlation coefficients betweensand and coarse fragments contents and WHC are docu-mented [52 53] meanwhile the negative correlation be-tween SOC and silt content is not in line with some results[44]

e statistical analysis of the studied soil propertiesfollowed a log-normal distribution as revealed by the co-efficient of kurtosis and skewness indicating possible an-thropogenic disturbances Under natural grasslands manysoil variables tend to conform to normal distribution due tothe homogenization effect of biotic factors [54] Followingirrigation or rainfall that saturates the soil making its watercontent higher than FC there should normally be adownward movement of water by gravity action Infiltrationis related to hydraulic conductivity that leads to decrease insoil moisture content as infiltration leads to soil water loss

42 Implications of theGleysolsCharacteristics onAgriculturalManagement Strategies In the Bamenda wetlands waterlosses often attain WP in the dry season making plant-available water contents low is condition of water stresshas been reported to cause drastic decrease in yields inwetlands [55] erefore for irrigation the ldquoplant readilyavailable waterrdquo constitutes the ideal operating range of soilmoisture for irrigation management [29 56] us irriga-tion scheduling should involve the replacement of depletedwater not higher than the FC to avoid waterlogging in thesesoils as drainage andor deep percolation is poor But sincethe soils are flooded in the rainy season it implies that theirwater content is above the FC and thus necessitating thedrainage of excess water during farming in the rainy seasone soil water characteristic curves become an indispensableto design irrigation schedules especially in the dry seasonduring moisture deficiency or to drain excess water in therainy season [57ndash59]

To achieve high yields without creating excess drainageit is necessary to know the crop readily available to becultivated After readily available water has been used plantroots cannot easily extract water and nutrients from the soil

Table 9 List of Ramsar sites in Cameroon [15]

SN Site Ramsar

identifierDesignation

date Region Geographic coordinates Altitude(m)

Surface area(km2)

1 Waza-Logone floodplain 1609 26052006 ExtremeNorth

11deg 37prime 59primeNorth14deg 37prime 01prime East 300 6000

2 Barombi-Mbo Lake 1643 810rsquo2006 South west 4deg 40prime 01primeNorth9deg 22prime 59primeEast 301ndash400 415

3 Cameroon section of theSangha River 1739 2022008 East 1deg 49prime 59primeNorth

16deg 01prime 59primeEast 350ndash700 62

4 Cameroon section of LakeChad 1903 2022010 Extreme

North12deg 46prime 01primeNorth14deg18prime 00primeEast 160ndash280 125

5 Rio Del Rey Estuary 1908 20052010 South West 4deg 37prime 01primeNorth8deg 43prime 01prime East 5 1650

6 Cameroon section of theNtem River 2067 5062012 South 2deg 22prime 44primeNorth

10deg 33prime14primeEast 400ndash526 39848

7 Ebogo Humid Zone 2028 605 2012 Centre 3deg 23prime10primeNorth11deg 29prime 20primeEast 630ndash670 3097

Applied and Environmental Soil Science 11

and this is the time to irrigate or refill pointe drier the soilis the more water it needs to return to field capacityus inirrigation FC and refill point are critical values for thecorrect use of many of the soil water monitoring

e high clay content of the Gleysols in the Bamendawetlands makes tillage and weed control in these areasdifficult due to the presence of water and sticky nature ofsoils to farm tools e high bulk density of the Gleysols isvery high (16 gmiddotcmminus3) compared to the optimum value(133 gmiddotcmminus3) for root penetration but also close to the upperlimit (175 gmiddotcmminus3) for root growth and is therefore a lim-iting factor to agriculture [60] High bulk density impliesthat the soils are not well aerated as most of the pores aresaturated with water during wet conditions

e highly significant correlation between clay and or-ganic matter contents reveals that both are linked together toform organo-mineral complexes and thus the SOC is beingprotected by soil matrix ese two soil colloids play a vital

role in the retention of water and nutrients for crop needs asrevealed by their high correlation with most of the moisturecharacteristicse high SOC implies a high cation exchangecapacity (CEC) e overall CEC of SOC and clay contentsfavors the retention and availability of nutrients to maintaincrop production in those Gleysols [60ndash62]

Particle size distribution also conditions chemical nu-trient supply [63] Most of the studied Gleysols samples haveclay plus silt content greater than 35 this indicates poornutrient assimilation by plants A correlation has also beenestablished between particle size distribution and yields [63]e (silt + sand)-to-total earth ratios of the Gleysols werevery high (gtgt35) relative to the ratio range of 15 to 35necessary for optimum yields and indicate potentially pooryields for a majority of tropical crops [63]

e SOCS of the Bamenda wetlands Gleysols is very high(gt200Mgmiddothaminus1) as such wetlands especially floodplains areoften very productive [4] Such ecosystems have the ability of

(a) (b)

(c) (d)

(e) (f )

Figure 6 Photographs of wetland ecosystems in Nkwen (Bamenda) (a) Wetland with grassed vegetation (b) water retained in furrows ofraised ridges (c d) channeling of water into farmlands for irrigation (e f ) healthy maize crops cultivated in the wetlands of Bamenda

12 Applied and Environmental Soil Science

sequestering and storing carbon through photosynthesis andorganic matter accumulation in soils and plant biomassthereby offering the opportunity for regaining lost pro-ductivity especially under agricultural systems e prop-erties of these studied soils could be similar to those of someRamsar sites in Cameroon although with some site specificfeatures Table 9 shows different Ramsar sites in Cameroon

5 Conclusion

In Bamenda City (Northwest Cameroon) population in-crease has led to considerable lawless occupation of wetlandsespecially as these areas are very fertile and support year-round agriculture Land use is often done without necessarytechnical know-how of sustainable land managementtechniques is work was focused on the determination ofmoisture characteristics of Gleysols in the Bamenda wet-lands and to establish a link between them and selected soilcharacteristics affecting crop production

e major findings revealed that the Gleysols showedvery high organic carbon contents and very high soil organiccarbon stocks implying a high level of carbon sequestrationMajor constraints of the soils to farming were clay plus siltcontents massive structure and waterlogging e moistureproperties revealed very high water-holding capacity andvery high plant-available water e particle density andcoarse fragments and sand contents correlated negativelywith the soil moisture retention characteristics and could bereducing the soilrsquos water-holding capacity e soil moisturecharacteristics curves were sigmoid-shaped and their heightsdecreased from upstream to downstream probably por-traying increase of finer material with fluvial transportdistant

e present work might have been limited in terms ofthe inadequate number of samples studied Further re-search is necessary on these wetland soils of the northwestregion of Cameroon to evaluate their potential risk ofdegradation based on a higher number of samples Alsothe results presented in this work might have been biasedbased on the fact that the tests were conducted solely inthe laboratory In the future measurements of waterstorage capacity of these soils should be done directly inthe field using more accurate methods such as electricalresistance and tensiometric and heat-diffusion methodsIrrigation schedules on this these soils should involve thereplacement of depleted water with water amounts notexceeding the FC to avoid waterlogging in these soils asdrainage andor deep percolation is poor Adapted cropslike lowland rice could also be introduced to extend thesurfaces of rice cultivation in the zone

Data Availability

Data can be made available on request

Conflicts of Interest

e authors declare no conflicts of interest

References

[1] W J Rawls T J Gish and D L Brakensiek ldquoEstimating soilwater retention from soil physical properties and character-isticsrdquoAdvances in Soil Science vol 16 pp 213ndash234 Springer-Verlag New York Inc NY USA 1991

[2] E Kellner and S Halldin ldquoWater budget and surface-layerwater storage in a Sphagnum bog in central Swedenrdquo Hy-drological Processes vol 16 no 1 pp 87ndash103 2002

[3] R M Khalid and H A K Ahmed ldquoNature of soil-watercharacteristics curves (SWCC) for soils from Anbar Gover-noraterdquo Anbar Journal of Engineering Sciences vol 3 no 1pp 61ndash80 2010

[4] e Ramsar Convention on Wetlands ldquoClimate Change andWetlands Resolution X24rdquo in Proceedings of the 10thMeeting of the Conference of the Parties to the Convention onWetlands Changwon Republic of Korea October 2008httpswwwramsarorgdocumentresolution-x24-climate-change-and-wetlands

[5] J Vopravil P Formanek and T Khel ldquoComparison of thephysical properties of soils belonging to different referencesoil groupsrdquo Soil andWater Research vol 16 pp 29ndash38 2021

[6] USDA Soil Survey Manual USDA Washington D C USA2017

[7] S R Carpenter W A Brock and P Hanson ldquoResilientmanagement comments onrdquo Ecological and Social Dynamics inSimple Models of EcosystemManagement Conservation EcologyResilience Alliance vol 3 no 2 Wisconsin USA 1999

[8] K E Saxton and W J Rawls ldquoSoil water characteristic es-timates by texture and organic matter for hydrologic solu-tionsrdquo Soil Science Society of America Journal vol 70 no 5pp 1569ndash1578 2006

[9] P A Tamfuh A H Chotangui A H Chotangui et al ldquoLandcharacteristics and agricultural suitability status along a top-osequence in Santa Bamenda Highlands Cameroonrdquo Journalof Atmospheric amp Earth Science vol 4 no 1 pp 1ndash9 2020

[10] A Kagou Dongmo C S Guedjeo P Azinwi Tamfuh et alldquoGeochemical and geotechnical characterization of soils de-veloped on volcanic rocks in the Bamenda Mountain(Cameroon volcanic line)rdquo International Journal of AdvancedGeosciences vol 6 no 2 pp 184ndash194 2018

[11] B Minasny and A E Hartemink ldquoPredicting soil propertiesin the tropicsrdquo Earth-Science Reviews vol 106 no 1-2pp 52ndash62 2011

[12] D Baros and A Albernaz ldquoPossible impacts of climate changeon wetlands and its biota in the Brazilian Amazonrdquo BrazilianJournal of Biology vol 74 no 4 pp 810ndash820 2014

[13] P Azinwi Tamfuh E Djoufac Woumfo E TemgouaA Boukong and D Bitom ldquoMoisture moisture-relatedproperties and agricultural management strategies of theBenue floodplain Vertisols in North Cameroonrdquo AfricanJournal of Agricultural Research vol 13 no 33 pp 1730ndash1746 2018

[14] IPCC (Intergovernmental Panel on Climate Change) ldquoCli-mate change 2013 the physical science basisrdquo in Contributionof Working Group I to the Fifth Assessment Report of theIntergovernmental Panel on Climate Change T F StockerD Qin G-K Plattner et al Eds Cambridge University PressCambridge UK 2013 httpwwwipccchreportar5wg1

[15] Ramsar Sites Information Service Annotated List of Wetlandsof International Importance Cameroon Ramsar Sites Infor-mation Service Gland Switzerland 2016 httpsrsisramsarorgfrris-searchlanguageframpf[0]regioncountry_fr_ss3ACameroon

Applied and Environmental Soil Science 13

e soil moisture characteristics increased considerablyfrom upstream at Mile 4 Nkwen to downstream atNgomgham Mulang below Foncha and Ntamulung ismight be related to transport and deposition of fine earthmaterial from upstream to downstream and to the geo-morphological configuration of the studied site or even tospecific soil characteristics like the mineralogical composi-tion of the clayey fraction Also several soil internal factorsmay be responsible for the variation in the soil moistureretention curve per site such as nonuniformity of porescontact angle difference and entrapped air in pore space[42]

e capillary water of the wetland soils was high as thiswater fraction is held to soil particles by weak surface tensionforces of soil particles and is thus available to plants Duringconditions of water stress (particularly during the dry season)capillarity plays a vital role in maintaining crop performancee soil water loss is faster at the surface than at depth causinga higher water tension at the surface than at depth [43 44] Itcauses a higher water tension at the surface than at depth andthis creates a water capillary current which moves from baseto surface and hence water rises to the surface to be availableto plants [45 46]e FC andWP are primarily influenced byirregular pore geometry and discontinuity and variations intexture and mineralogy [47ndash50]

In this study clay content of the soils correlated best withthe moisture characteristics more than any other propertye clay and SOC contents probably linked together asrevealed by their significant positive correlation favor theoccurrence of micropores and menisci that generate capil-lary forcesus they increase the specific surface area of thesoil matrix and consequently water adsorption [48] Al-though siltclay ratio displays no significant correlation withsoil moisture characteristics it negatively strongly correlateswith SOC e size and structure of clay particles were moresuitable for association with SOM molecules than the sizeand the structure of bigger soil particles [49] e clay andSOC contents are indispensable in the water and nutrientretention for plants based on their high specific surface area[50] Sand and coarse fragments contents tend to increasesoil particle density thereby increasing macroporosity and

reducing microporosity hence lowering the soil capacity toretain water [51] us low correlation coefficients betweensand and coarse fragments contents and WHC are docu-mented [52 53] meanwhile the negative correlation be-tween SOC and silt content is not in line with some results[44]

e statistical analysis of the studied soil propertiesfollowed a log-normal distribution as revealed by the co-efficient of kurtosis and skewness indicating possible an-thropogenic disturbances Under natural grasslands manysoil variables tend to conform to normal distribution due tothe homogenization effect of biotic factors [54] Followingirrigation or rainfall that saturates the soil making its watercontent higher than FC there should normally be adownward movement of water by gravity action Infiltrationis related to hydraulic conductivity that leads to decrease insoil moisture content as infiltration leads to soil water loss

42 Implications of theGleysolsCharacteristics onAgriculturalManagement Strategies In the Bamenda wetlands waterlosses often attain WP in the dry season making plant-available water contents low is condition of water stresshas been reported to cause drastic decrease in yields inwetlands [55] erefore for irrigation the ldquoplant readilyavailable waterrdquo constitutes the ideal operating range of soilmoisture for irrigation management [29 56] us irriga-tion scheduling should involve the replacement of depletedwater not higher than the FC to avoid waterlogging in thesesoils as drainage andor deep percolation is poor But sincethe soils are flooded in the rainy season it implies that theirwater content is above the FC and thus necessitating thedrainage of excess water during farming in the rainy seasone soil water characteristic curves become an indispensableto design irrigation schedules especially in the dry seasonduring moisture deficiency or to drain excess water in therainy season [57ndash59]

To achieve high yields without creating excess drainageit is necessary to know the crop readily available to becultivated After readily available water has been used plantroots cannot easily extract water and nutrients from the soil

Table 9 List of Ramsar sites in Cameroon [15]

SN Site Ramsar

identifierDesignation

date Region Geographic coordinates Altitude(m)

Surface area(km2)

1 Waza-Logone floodplain 1609 26052006 ExtremeNorth

11deg 37prime 59primeNorth14deg 37prime 01prime East 300 6000

2 Barombi-Mbo Lake 1643 810rsquo2006 South west 4deg 40prime 01primeNorth9deg 22prime 59primeEast 301ndash400 415

3 Cameroon section of theSangha River 1739 2022008 East 1deg 49prime 59primeNorth

16deg 01prime 59primeEast 350ndash700 62

4 Cameroon section of LakeChad 1903 2022010 Extreme

North12deg 46prime 01primeNorth14deg18prime 00primeEast 160ndash280 125

5 Rio Del Rey Estuary 1908 20052010 South West 4deg 37prime 01primeNorth8deg 43prime 01prime East 5 1650

6 Cameroon section of theNtem River 2067 5062012 South 2deg 22prime 44primeNorth

10deg 33prime14primeEast 400ndash526 39848

7 Ebogo Humid Zone 2028 605 2012 Centre 3deg 23prime10primeNorth11deg 29prime 20primeEast 630ndash670 3097

Applied and Environmental Soil Science 11

and this is the time to irrigate or refill pointe drier the soilis the more water it needs to return to field capacityus inirrigation FC and refill point are critical values for thecorrect use of many of the soil water monitoring

e high clay content of the Gleysols in the Bamendawetlands makes tillage and weed control in these areasdifficult due to the presence of water and sticky nature ofsoils to farm tools e high bulk density of the Gleysols isvery high (16 gmiddotcmminus3) compared to the optimum value(133 gmiddotcmminus3) for root penetration but also close to the upperlimit (175 gmiddotcmminus3) for root growth and is therefore a lim-iting factor to agriculture [60] High bulk density impliesthat the soils are not well aerated as most of the pores aresaturated with water during wet conditions

e highly significant correlation between clay and or-ganic matter contents reveals that both are linked together toform organo-mineral complexes and thus the SOC is beingprotected by soil matrix ese two soil colloids play a vital

role in the retention of water and nutrients for crop needs asrevealed by their high correlation with most of the moisturecharacteristicse high SOC implies a high cation exchangecapacity (CEC) e overall CEC of SOC and clay contentsfavors the retention and availability of nutrients to maintaincrop production in those Gleysols [60ndash62]

Particle size distribution also conditions chemical nu-trient supply [63] Most of the studied Gleysols samples haveclay plus silt content greater than 35 this indicates poornutrient assimilation by plants A correlation has also beenestablished between particle size distribution and yields [63]e (silt + sand)-to-total earth ratios of the Gleysols werevery high (gtgt35) relative to the ratio range of 15 to 35necessary for optimum yields and indicate potentially pooryields for a majority of tropical crops [63]

e SOCS of the Bamenda wetlands Gleysols is very high(gt200Mgmiddothaminus1) as such wetlands especially floodplains areoften very productive [4] Such ecosystems have the ability of

(a) (b)

(c) (d)

(e) (f )

Figure 6 Photographs of wetland ecosystems in Nkwen (Bamenda) (a) Wetland with grassed vegetation (b) water retained in furrows ofraised ridges (c d) channeling of water into farmlands for irrigation (e f ) healthy maize crops cultivated in the wetlands of Bamenda

12 Applied and Environmental Soil Science

sequestering and storing carbon through photosynthesis andorganic matter accumulation in soils and plant biomassthereby offering the opportunity for regaining lost pro-ductivity especially under agricultural systems e prop-erties of these studied soils could be similar to those of someRamsar sites in Cameroon although with some site specificfeatures Table 9 shows different Ramsar sites in Cameroon

5 Conclusion

In Bamenda City (Northwest Cameroon) population in-crease has led to considerable lawless occupation of wetlandsespecially as these areas are very fertile and support year-round agriculture Land use is often done without necessarytechnical know-how of sustainable land managementtechniques is work was focused on the determination ofmoisture characteristics of Gleysols in the Bamenda wet-lands and to establish a link between them and selected soilcharacteristics affecting crop production

e major findings revealed that the Gleysols showedvery high organic carbon contents and very high soil organiccarbon stocks implying a high level of carbon sequestrationMajor constraints of the soils to farming were clay plus siltcontents massive structure and waterlogging e moistureproperties revealed very high water-holding capacity andvery high plant-available water e particle density andcoarse fragments and sand contents correlated negativelywith the soil moisture retention characteristics and could bereducing the soilrsquos water-holding capacity e soil moisturecharacteristics curves were sigmoid-shaped and their heightsdecreased from upstream to downstream probably por-traying increase of finer material with fluvial transportdistant

e present work might have been limited in terms ofthe inadequate number of samples studied Further re-search is necessary on these wetland soils of the northwestregion of Cameroon to evaluate their potential risk ofdegradation based on a higher number of samples Alsothe results presented in this work might have been biasedbased on the fact that the tests were conducted solely inthe laboratory In the future measurements of waterstorage capacity of these soils should be done directly inthe field using more accurate methods such as electricalresistance and tensiometric and heat-diffusion methodsIrrigation schedules on this these soils should involve thereplacement of depleted water with water amounts notexceeding the FC to avoid waterlogging in these soils asdrainage andor deep percolation is poor Adapted cropslike lowland rice could also be introduced to extend thesurfaces of rice cultivation in the zone

Data Availability

Data can be made available on request

Conflicts of Interest

e authors declare no conflicts of interest

References

[1] W J Rawls T J Gish and D L Brakensiek ldquoEstimating soilwater retention from soil physical properties and character-isticsrdquoAdvances in Soil Science vol 16 pp 213ndash234 Springer-Verlag New York Inc NY USA 1991

[2] E Kellner and S Halldin ldquoWater budget and surface-layerwater storage in a Sphagnum bog in central Swedenrdquo Hy-drological Processes vol 16 no 1 pp 87ndash103 2002

[3] R M Khalid and H A K Ahmed ldquoNature of soil-watercharacteristics curves (SWCC) for soils from Anbar Gover-noraterdquo Anbar Journal of Engineering Sciences vol 3 no 1pp 61ndash80 2010

[4] e Ramsar Convention on Wetlands ldquoClimate Change andWetlands Resolution X24rdquo in Proceedings of the 10thMeeting of the Conference of the Parties to the Convention onWetlands Changwon Republic of Korea October 2008httpswwwramsarorgdocumentresolution-x24-climate-change-and-wetlands

[5] J Vopravil P Formanek and T Khel ldquoComparison of thephysical properties of soils belonging to different referencesoil groupsrdquo Soil andWater Research vol 16 pp 29ndash38 2021

[6] USDA Soil Survey Manual USDA Washington D C USA2017

[7] S R Carpenter W A Brock and P Hanson ldquoResilientmanagement comments onrdquo Ecological and Social Dynamics inSimple Models of EcosystemManagement Conservation EcologyResilience Alliance vol 3 no 2 Wisconsin USA 1999

[8] K E Saxton and W J Rawls ldquoSoil water characteristic es-timates by texture and organic matter for hydrologic solu-tionsrdquo Soil Science Society of America Journal vol 70 no 5pp 1569ndash1578 2006

[9] P A Tamfuh A H Chotangui A H Chotangui et al ldquoLandcharacteristics and agricultural suitability status along a top-osequence in Santa Bamenda Highlands Cameroonrdquo Journalof Atmospheric amp Earth Science vol 4 no 1 pp 1ndash9 2020

[10] A Kagou Dongmo C S Guedjeo P Azinwi Tamfuh et alldquoGeochemical and geotechnical characterization of soils de-veloped on volcanic rocks in the Bamenda Mountain(Cameroon volcanic line)rdquo International Journal of AdvancedGeosciences vol 6 no 2 pp 184ndash194 2018

[11] B Minasny and A E Hartemink ldquoPredicting soil propertiesin the tropicsrdquo Earth-Science Reviews vol 106 no 1-2pp 52ndash62 2011

[12] D Baros and A Albernaz ldquoPossible impacts of climate changeon wetlands and its biota in the Brazilian Amazonrdquo BrazilianJournal of Biology vol 74 no 4 pp 810ndash820 2014

[13] P Azinwi Tamfuh E Djoufac Woumfo E TemgouaA Boukong and D Bitom ldquoMoisture moisture-relatedproperties and agricultural management strategies of theBenue floodplain Vertisols in North Cameroonrdquo AfricanJournal of Agricultural Research vol 13 no 33 pp 1730ndash1746 2018

[14] IPCC (Intergovernmental Panel on Climate Change) ldquoCli-mate change 2013 the physical science basisrdquo in Contributionof Working Group I to the Fifth Assessment Report of theIntergovernmental Panel on Climate Change T F StockerD Qin G-K Plattner et al Eds Cambridge University PressCambridge UK 2013 httpwwwipccchreportar5wg1

[15] Ramsar Sites Information Service Annotated List of Wetlandsof International Importance Cameroon Ramsar Sites Infor-mation Service Gland Switzerland 2016 httpsrsisramsarorgfrris-searchlanguageframpf[0]regioncountry_fr_ss3ACameroon

Applied and Environmental Soil Science 13

and this is the time to irrigate or refill pointe drier the soilis the more water it needs to return to field capacityus inirrigation FC and refill point are critical values for thecorrect use of many of the soil water monitoring

e high clay content of the Gleysols in the Bamendawetlands makes tillage and weed control in these areasdifficult due to the presence of water and sticky nature ofsoils to farm tools e high bulk density of the Gleysols isvery high (16 gmiddotcmminus3) compared to the optimum value(133 gmiddotcmminus3) for root penetration but also close to the upperlimit (175 gmiddotcmminus3) for root growth and is therefore a lim-iting factor to agriculture [60] High bulk density impliesthat the soils are not well aerated as most of the pores aresaturated with water during wet conditions

e highly significant correlation between clay and or-ganic matter contents reveals that both are linked together toform organo-mineral complexes and thus the SOC is beingprotected by soil matrix ese two soil colloids play a vital

role in the retention of water and nutrients for crop needs asrevealed by their high correlation with most of the moisturecharacteristicse high SOC implies a high cation exchangecapacity (CEC) e overall CEC of SOC and clay contentsfavors the retention and availability of nutrients to maintaincrop production in those Gleysols [60ndash62]

Particle size distribution also conditions chemical nu-trient supply [63] Most of the studied Gleysols samples haveclay plus silt content greater than 35 this indicates poornutrient assimilation by plants A correlation has also beenestablished between particle size distribution and yields [63]e (silt + sand)-to-total earth ratios of the Gleysols werevery high (gtgt35) relative to the ratio range of 15 to 35necessary for optimum yields and indicate potentially pooryields for a majority of tropical crops [63]

e SOCS of the Bamenda wetlands Gleysols is very high(gt200Mgmiddothaminus1) as such wetlands especially floodplains areoften very productive [4] Such ecosystems have the ability of

(a) (b)

(c) (d)

(e) (f )

Figure 6 Photographs of wetland ecosystems in Nkwen (Bamenda) (a) Wetland with grassed vegetation (b) water retained in furrows ofraised ridges (c d) channeling of water into farmlands for irrigation (e f ) healthy maize crops cultivated in the wetlands of Bamenda

12 Applied and Environmental Soil Science

sequestering and storing carbon through photosynthesis andorganic matter accumulation in soils and plant biomassthereby offering the opportunity for regaining lost pro-ductivity especially under agricultural systems e prop-erties of these studied soils could be similar to those of someRamsar sites in Cameroon although with some site specificfeatures Table 9 shows different Ramsar sites in Cameroon

5 Conclusion

In Bamenda City (Northwest Cameroon) population in-crease has led to considerable lawless occupation of wetlandsespecially as these areas are very fertile and support year-round agriculture Land use is often done without necessarytechnical know-how of sustainable land managementtechniques is work was focused on the determination ofmoisture characteristics of Gleysols in the Bamenda wet-lands and to establish a link between them and selected soilcharacteristics affecting crop production

e major findings revealed that the Gleysols showedvery high organic carbon contents and very high soil organiccarbon stocks implying a high level of carbon sequestrationMajor constraints of the soils to farming were clay plus siltcontents massive structure and waterlogging e moistureproperties revealed very high water-holding capacity andvery high plant-available water e particle density andcoarse fragments and sand contents correlated negativelywith the soil moisture retention characteristics and could bereducing the soilrsquos water-holding capacity e soil moisturecharacteristics curves were sigmoid-shaped and their heightsdecreased from upstream to downstream probably por-traying increase of finer material with fluvial transportdistant

e present work might have been limited in terms ofthe inadequate number of samples studied Further re-search is necessary on these wetland soils of the northwestregion of Cameroon to evaluate their potential risk ofdegradation based on a higher number of samples Alsothe results presented in this work might have been biasedbased on the fact that the tests were conducted solely inthe laboratory In the future measurements of waterstorage capacity of these soils should be done directly inthe field using more accurate methods such as electricalresistance and tensiometric and heat-diffusion methodsIrrigation schedules on this these soils should involve thereplacement of depleted water with water amounts notexceeding the FC to avoid waterlogging in these soils asdrainage andor deep percolation is poor Adapted cropslike lowland rice could also be introduced to extend thesurfaces of rice cultivation in the zone

Data Availability

Data can be made available on request

Conflicts of Interest

e authors declare no conflicts of interest

References

[1] W J Rawls T J Gish and D L Brakensiek ldquoEstimating soilwater retention from soil physical properties and character-isticsrdquoAdvances in Soil Science vol 16 pp 213ndash234 Springer-Verlag New York Inc NY USA 1991

[2] E Kellner and S Halldin ldquoWater budget and surface-layerwater storage in a Sphagnum bog in central Swedenrdquo Hy-drological Processes vol 16 no 1 pp 87ndash103 2002

[3] R M Khalid and H A K Ahmed ldquoNature of soil-watercharacteristics curves (SWCC) for soils from Anbar Gover-noraterdquo Anbar Journal of Engineering Sciences vol 3 no 1pp 61ndash80 2010

[4] e Ramsar Convention on Wetlands ldquoClimate Change andWetlands Resolution X24rdquo in Proceedings of the 10thMeeting of the Conference of the Parties to the Convention onWetlands Changwon Republic of Korea October 2008httpswwwramsarorgdocumentresolution-x24-climate-change-and-wetlands

[5] J Vopravil P Formanek and T Khel ldquoComparison of thephysical properties of soils belonging to different referencesoil groupsrdquo Soil andWater Research vol 16 pp 29ndash38 2021

[6] USDA Soil Survey Manual USDA Washington D C USA2017

[7] S R Carpenter W A Brock and P Hanson ldquoResilientmanagement comments onrdquo Ecological and Social Dynamics inSimple Models of EcosystemManagement Conservation EcologyResilience Alliance vol 3 no 2 Wisconsin USA 1999

[8] K E Saxton and W J Rawls ldquoSoil water characteristic es-timates by texture and organic matter for hydrologic solu-tionsrdquo Soil Science Society of America Journal vol 70 no 5pp 1569ndash1578 2006

[9] P A Tamfuh A H Chotangui A H Chotangui et al ldquoLandcharacteristics and agricultural suitability status along a top-osequence in Santa Bamenda Highlands Cameroonrdquo Journalof Atmospheric amp Earth Science vol 4 no 1 pp 1ndash9 2020

[10] A Kagou Dongmo C S Guedjeo P Azinwi Tamfuh et alldquoGeochemical and geotechnical characterization of soils de-veloped on volcanic rocks in the Bamenda Mountain(Cameroon volcanic line)rdquo International Journal of AdvancedGeosciences vol 6 no 2 pp 184ndash194 2018

[11] B Minasny and A E Hartemink ldquoPredicting soil propertiesin the tropicsrdquo Earth-Science Reviews vol 106 no 1-2pp 52ndash62 2011

[12] D Baros and A Albernaz ldquoPossible impacts of climate changeon wetlands and its biota in the Brazilian Amazonrdquo BrazilianJournal of Biology vol 74 no 4 pp 810ndash820 2014

[13] P Azinwi Tamfuh E Djoufac Woumfo E TemgouaA Boukong and D Bitom ldquoMoisture moisture-relatedproperties and agricultural management strategies of theBenue floodplain Vertisols in North Cameroonrdquo AfricanJournal of Agricultural Research vol 13 no 33 pp 1730ndash1746 2018

[14] IPCC (Intergovernmental Panel on Climate Change) ldquoCli-mate change 2013 the physical science basisrdquo in Contributionof Working Group I to the Fifth Assessment Report of theIntergovernmental Panel on Climate Change T F StockerD Qin G-K Plattner et al Eds Cambridge University PressCambridge UK 2013 httpwwwipccchreportar5wg1

[15] Ramsar Sites Information Service Annotated List of Wetlandsof International Importance Cameroon Ramsar Sites Infor-mation Service Gland Switzerland 2016 httpsrsisramsarorgfrris-searchlanguageframpf[0]regioncountry_fr_ss3ACameroon

Applied and Environmental Soil Science 13

sequestering and storing carbon through photosynthesis andorganic matter accumulation in soils and plant biomassthereby offering the opportunity for regaining lost pro-ductivity especially under agricultural systems e prop-erties of these studied soils could be similar to those of someRamsar sites in Cameroon although with some site specificfeatures Table 9 shows different Ramsar sites in Cameroon

5 Conclusion

In Bamenda City (Northwest Cameroon) population in-crease has led to considerable lawless occupation of wetlandsespecially as these areas are very fertile and support year-round agriculture Land use is often done without necessarytechnical know-how of sustainable land managementtechniques is work was focused on the determination ofmoisture characteristics of Gleysols in the Bamenda wet-lands and to establish a link between them and selected soilcharacteristics affecting crop production

e major findings revealed that the Gleysols showedvery high organic carbon contents and very high soil organiccarbon stocks implying a high level of carbon sequestrationMajor constraints of the soils to farming were clay plus siltcontents massive structure and waterlogging e moistureproperties revealed very high water-holding capacity andvery high plant-available water e particle density andcoarse fragments and sand contents correlated negativelywith the soil moisture retention characteristics and could bereducing the soilrsquos water-holding capacity e soil moisturecharacteristics curves were sigmoid-shaped and their heightsdecreased from upstream to downstream probably por-traying increase of finer material with fluvial transportdistant

e present work might have been limited in terms ofthe inadequate number of samples studied Further re-search is necessary on these wetland soils of the northwestregion of Cameroon to evaluate their potential risk ofdegradation based on a higher number of samples Alsothe results presented in this work might have been biasedbased on the fact that the tests were conducted solely inthe laboratory In the future measurements of waterstorage capacity of these soils should be done directly inthe field using more accurate methods such as electricalresistance and tensiometric and heat-diffusion methodsIrrigation schedules on this these soils should involve thereplacement of depleted water with water amounts notexceeding the FC to avoid waterlogging in these soils asdrainage andor deep percolation is poor Adapted cropslike lowland rice could also be introduced to extend thesurfaces of rice cultivation in the zone

Data Availability

Data can be made available on request

Conflicts of Interest

e authors declare no conflicts of interest

References

[1] W J Rawls T J Gish and D L Brakensiek ldquoEstimating soilwater retention from soil physical properties and character-isticsrdquoAdvances in Soil Science vol 16 pp 213ndash234 Springer-Verlag New York Inc NY USA 1991

[2] E Kellner and S Halldin ldquoWater budget and surface-layerwater storage in a Sphagnum bog in central Swedenrdquo Hy-drological Processes vol 16 no 1 pp 87ndash103 2002

[3] R M Khalid and H A K Ahmed ldquoNature of soil-watercharacteristics curves (SWCC) for soils from Anbar Gover-noraterdquo Anbar Journal of Engineering Sciences vol 3 no 1pp 61ndash80 2010

[4] e Ramsar Convention on Wetlands ldquoClimate Change andWetlands Resolution X24rdquo in Proceedings of the 10thMeeting of the Conference of the Parties to the Convention onWetlands Changwon Republic of Korea October 2008httpswwwramsarorgdocumentresolution-x24-climate-change-and-wetlands

[5] J Vopravil P Formanek and T Khel ldquoComparison of thephysical properties of soils belonging to different referencesoil groupsrdquo Soil andWater Research vol 16 pp 29ndash38 2021

[6] USDA Soil Survey Manual USDA Washington D C USA2017

[7] S R Carpenter W A Brock and P Hanson ldquoResilientmanagement comments onrdquo Ecological and Social Dynamics inSimple Models of EcosystemManagement Conservation EcologyResilience Alliance vol 3 no 2 Wisconsin USA 1999

[8] K E Saxton and W J Rawls ldquoSoil water characteristic es-timates by texture and organic matter for hydrologic solu-tionsrdquo Soil Science Society of America Journal vol 70 no 5pp 1569ndash1578 2006

[9] P A Tamfuh A H Chotangui A H Chotangui et al ldquoLandcharacteristics and agricultural suitability status along a top-osequence in Santa Bamenda Highlands Cameroonrdquo Journalof Atmospheric amp Earth Science vol 4 no 1 pp 1ndash9 2020

[10] A Kagou Dongmo C S Guedjeo P Azinwi Tamfuh et alldquoGeochemical and geotechnical characterization of soils de-veloped on volcanic rocks in the Bamenda Mountain(Cameroon volcanic line)rdquo International Journal of AdvancedGeosciences vol 6 no 2 pp 184ndash194 2018

[11] B Minasny and A E Hartemink ldquoPredicting soil propertiesin the tropicsrdquo Earth-Science Reviews vol 106 no 1-2pp 52ndash62 2011

[12] D Baros and A Albernaz ldquoPossible impacts of climate changeon wetlands and its biota in the Brazilian Amazonrdquo BrazilianJournal of Biology vol 74 no 4 pp 810ndash820 2014

[13] P Azinwi Tamfuh E Djoufac Woumfo E TemgouaA Boukong and D Bitom ldquoMoisture moisture-relatedproperties and agricultural management strategies of theBenue floodplain Vertisols in North Cameroonrdquo AfricanJournal of Agricultural Research vol 13 no 33 pp 1730ndash1746 2018

[14] IPCC (Intergovernmental Panel on Climate Change) ldquoCli-mate change 2013 the physical science basisrdquo in Contributionof Working Group I to the Fifth Assessment Report of theIntergovernmental Panel on Climate Change T F StockerD Qin G-K Plattner et al Eds Cambridge University PressCambridge UK 2013 httpwwwipccchreportar5wg1

[15] Ramsar Sites Information Service Annotated List of Wetlandsof International Importance Cameroon Ramsar Sites Infor-mation Service Gland Switzerland 2016 httpsrsisramsarorgfrris-searchlanguageframpf[0]regioncountry_fr_ss3ACameroon

Applied and Environmental Soil Science 13

[16] A Magha M A Tita G D Kouankap P WotchokoA Tabot and V K B Kamgang ldquoPhysico-chemical andbacteriological characterization of spring and well water inBamenda III (NW region Cameroon)rdquo American Journal ofEnvironmental Protection vol 4 no 3 pp 163ndash173 2015

[17] S S Kometa ldquoWetlands exploitation along the Bafoussam -Bamenda road axis of the Western Highlands of CameroonrdquoJournal of Human Ecology vol 41 no 1 pp 25ndash32 2013

[18] E M Nyambod ldquoEnvironmental consequences of rapid ur-banisation Bamenda city Cameroonrdquo Journal of Environ-mental Protection vol 1 no 1 pp 15ndash23 2010

[19] M A Tita G N Tsala and K V B Kamgang ldquoLevels ofmetals in huckleberry (Solanum scabrum) grown along theMezam river banks Bamenda North-West Cameroon im-plications for crops growth and human consumptionrdquo Syl-labus Review vol 2 no 2 pp 69ndash78 2011

[20] C Acho ldquoHuman interference and environmental instabilityaddressing the environmental consequences of rapid urbangrowth in Bamendardquo Environment and Urbanization vol 10no 2 pp 161ndash174 1998

[21] A G Asongwe P K Y Bernard and A S Tening ldquoSpatialvariability of selected physico-chemical properties of soilsunder vegetable cultivation in urban and peri-urban wetlandgardens of Bamenda municipality Cameroonrdquo African Journalof Agricultural Research vol 11 no 2 pp 74ndash86 2016

[22] N A Mofor N E B Tamungang K MbeneN B Yuhinwenkeh and F B Nchofua ldquoTrace element statusand environmental implications of soils and Zea mays fromfarmed dumpsites in the Bamenda metropolis North westCameroonrdquo Applied and Environmental Soil Sciencevol 2020 Article ID 8861102 9 pages 2020

[23] C S Guedjeo A Kagou Dongmo F Ngapgue et al ldquoNaturalhazards along the Bamenda escarpment and its environs thecase of landslide rock fall and flood risksrdquo Journal of Geologyand Mining Research vol 2 pp 15ndash26 2012

[24] R N Afungang C A Nkwemoh and R Ngoufo ldquoSpatialmodelling of landslide susceptibility using logistic regressionmodel in the Bamenda Escarpment zone NW CameroonrdquoInternational Journal of Innovative Research and Develop-ment vol 6 no 12 pp 187ndash199 2017

[25] P Kamgang E Njonfang G Chazot and F TchoualdquoGeochimie et geochronologie des laves felsiques des montsBamenda (ligne volcanique du Cameroun)rdquo Comptes RendusGeoscience vol 339 no 10 pp 659ndash666 2007

[26] E N Ndenecho and B Eze ldquoGeomorphic and anthropogenicfactors influencing landslides in the Bamenda Highlands(North West province Cameroon)rdquo Journal of Applied SocialSciences vol 4 no 1 pp 15ndash26 2004

[27] LVanReeuwijk ldquoProcedures for Soil Analysisrdquo in Sulitjelmafeltetsgeologi og petrografi Norge sGeologisk eUndersokelse T Vogt Edvol 121 pp 1ndash560 ISRIC-FAO Wageningen Netherlands 1927

[28] FAO (Food and Agriculture Organization) Guidelines for SoilDescription a Framework for International ClassificationCorrelation and Communication FAO Rome Italy 2006

[29] B Jabiol Lrsquoeau dans le sol FIF-ENGREF Paris France 2001[30] K S Grewal G D Buchan and P J Tonkin ldquoEstimation of

field capacity and wilting point of someNew Zealand soils fromtheir saturation percentagesrdquoNew Zealand Journal of Crop andHorticultural Science vol 18 no 4 pp 241ndash246 1990

[31] M Vilain La Production Vegetalerdquo editeur LAVOISIERTEC ET DOC collection Agriculture daujourdhui vol 2Paris France 1997 httpswwwunithequecomLivreLavoisier-tec_et_docAgriculture_d_aujourd_huiLa_production_vegetale_Volume_ 2-33593html

[32] H Baize and B Jabiol Guide Pour la Description des solsMasson Paris France 1er edition 1995

[33] J Lozet and C Mathieu Dictionnaire de Science du Sol vol 8Karstologia Paris France 2eme edition 1986

[34] GEPPA (Groupe drsquoEtude des Problemes en PedologieAppliquee) Synthese des travaux de la Commission de car-tographie 1971ndash1981 GEPPA (Groupe drsquoEtude des Problemesen Pedologie Appliquee) Paris France 1981

[35] B D Reetashree B Das G Yam P Pankaj andO P Tripathi ldquoModeling water holding capacity using readilyavailable soil characteristicsrdquo Journal of Agricultural Researchvol 8 pp 347ndash355 2019

[36] R P Sharma P Raja and B P Bhaskar ldquoPedogenesis andmineralogy of alluvial soils from semi-arid South Eastern partof Rajasthan in Aravalli range Indiardquo Journal of the GeologicalSociety of India vol 95 no 1 pp 59ndash66 2020

[37] W G Sombroek and I S Zonneveld Ancient Dune Fields andFluviatiledeposits Soil Survey Institute of WageningenWageningen Netherlands 1971

[38] H C T Stace G D Hubble R Brewer et al A Handbook ofAustralian Soils Soil Science Society of America RelimTechnical Publications Glenside SA Adelaide Australia1968

[39] T N Jewitt R D Law and K J Virgo ldquoVertisol soils of thetropics and sub-tropics their management and userdquo Outlookon Agriculture vol 10 no 1 1979

[40] E A Gardner K J Coughlan and D M Silburn ldquoSoil watermeasurement and management of vertisols in Queensland(Australia)rdquo in Proceedings of the Conference on the Man-agement of Vertisols in Sub-saharan Africa pp 188ndash200Addis Ababa Ethiopia August 1987

[41] S S R Gidigasu and S K Y Gawu ldquoe mode of formationnature and geotechnical characteristics of black cotton soils - areviewrdquo Standard Scientific Research and Essays vol 1 no 14pp 377ndash390 2013

[42] S L J Page ldquoEffects of the physical properties of two tropicalCotton soils on their permanent wilting point and relativehumidity in relation to survival and distribution of Meloi-dogyne acroneardquo Revue Nematologique vol 7 no 3pp 227ndash232 1984

[43] G Haider T Hordofa and B Endale ldquoIrrigation watermanagement for cotton on vertisols in the middle awashregion of Ethiopiardquo in Proceedings of the Conference on theManagement of Vertisols in Sub-saharan Africa pp 166ndash182Addis Ababa Ethiopia August 1987

[44] J M Reichert J A Albuquerque D R Kaiser D J ReinertF Lavarda Urach and R Carlesso ldquoEstimation of water re-tention and availability in soils of Rio Grande do Sul RevistaBrasileira de Ciencia do Solordquo Sociedade Brasileira de Cienciado Solo Viccedilosa vol 33 no 6 pp 1547ndash1560 2009

[45] J M Reichert J A Albuquerque D J Reinert J E S Perezaand A Da Costa ldquoEstimating water retention and availabilityin cultivated soils of Southern Brazilrdquo Geoderma Regionalvol 21 2020

[46] J L Costa V Aparicio and A Cerda ldquoSoil physical qualitychanges under different management systems after 10 years inthe Argentine humid pampardquo Solid Earth vol 6 no 1pp 361ndash371 2015

[47] W J Rawls D L Brakensiek and K E Saxton Estimation ofSoil Water Properties pp 1316ndash1328 Transactions AmericanSociety of Agricultural Engineers Michigan USA 1982

[48] D Hillel Environmental Soil Physics Academic Press SanDiego USA 1998

14 Applied and Environmental Soil Science

[49] W G Sombroek and I S Zonneveld Ancient Dune Fields andFluviatile Deposits in the Rima-Sokoto River Basin (NWNigeria) Netherlands Soil Survey Institute WageningenNetherlands 1971

[50] W J Rawls Y A Pachepsky J C Ritchie T M Sobecki andH Bloodworth ldquoEffect of soil organic carbon on soil waterretentionrdquo Geoderma vol 116 no 1-2 pp 61ndash76 2003

[51] M Mecke C J Westman and H Ilvesniemi ldquoWater re-tention capacity in coarse Podzol profiles predicted frommeasured soil propertiesrdquo Soil Science Society of AmericaJournal vol 66 no 1 pp 1ndash11 2002

[52] M Van den Berg E Klamt L P Van Reeuwijk andW G Sombroek ldquoPedotransfer functions for the estimationof moisture retention characteristics of ferralsols and relatedsoilsrdquo Geoderma vol 78 no 3-4 pp 161ndash180 1997

[53] N F B Giarola A P silva and S Imhoff ldquoRelaccedilotildees entrepropriedades fısicas e caracterısticas de solos da Regiatildeo Sul doBrasilrdquo Revista Brasileira de Ciencia do Solo vol 26pp 885ndash893 2002

[54] R G D Steel and J H Torrie Principles and Procedures ofStatistics A Biometrical Approach McGraw-Hill NY USA2nd edition 1980

[55] D G Fredlund and A Xing ldquoEquations for the soil-watercharacteristic curverdquo Canadian Geotechnical Journal vol 31no 4 pp 521ndash532 1994

[56] A-M Laroche J Gallichand R Lagace and A PesantldquoSimulating atrazine transport with HSPF in an agriculturalwatershedrdquo Journal of Environmental Engineering vol 122no 7 pp 622ndash630 1996

[57] A D Costa J A Albuquerque J A D Almeida A D Costaand R V Luciano ldquoPedotransfer functions to estimate re-tention and availability of water in soils of the state of SantaCatarina Brazilrdquo Revista Brasileira de Ciencia do Solo vol 37no 4 pp 889ndash910 2013

[58] M P Nguyen V K Le and C WimHydrology in a ChangingWorld Environmental and Human Dimensions Proceedings ofFRIEND-Water 2014 vol 363 pp 392ndash398 IAHS Publica-tions Montpellier France 2014

[59] G A Asongwe P K B Yerima A S Tening andM E Sailieh ldquoFood security and environmental implicationsof urban wetlands utilisation as vegetable gardens the case ofBamendamunicipality Cameroonrdquo Journal of Agriculture andEnvironmental Sciences vol 6 no 1 pp 66ndash77 2017

[60] H E Igbadun M A Oyebode and A S MohammedldquoEvaluation of a simulation model for prediction soil water-characteristics of selected agricultural fieldsrdquoNigerian Journalof Technological Development vol 8 no 1 pp 61ndash73 2011

[61] T F Scherer D Franzen and K Cihacek Soil Water andPlant Characteristics Important to Irrigation North DakotaState University Fargo USA 2017 httpwwwagndsuedu

[62] J Perez-Rojas F Moreno J C Quevedo and J Villa ldquoSoilorganic carbon stocks in fluvial and isolated tropical wetlandsfrom Colombiardquo Catena vol 179 pp 139ndash148 2019

[63] M Lathan ldquoRole du facteur sol dans le developpement ducotonnier en Cote drsquoIvoirerdquo Cahiers Office de RechercheScientifique et Technique dOutre Mer Serie Pedologiquevol IX no 1 pp 29ndash42 1971

Applied and Environmental Soil Science 15