Land Degradation Assessment, Using Geospatial Technology

Land Degradation Assessment, Using Geospatial Technology in Sokoto State Dry Sub-humid Plain in North-western Nigeria

*Maniyunda, L. M. and Ya'u, S. L.

Department of Soil Science, Faculty of Agriculture/ Institute for Agricultural Research,

Ahmadu Bello University, P.M.B. 1044, Samaru, Zaria, Nigeria

*Corresponding author's e- mail: [email protected]

ABSTRACT

The use of satellite imagery (SI) and geographic information system (GIS) is key to successful assessment of terrestrial biomes covering large area at state or regional levels. This study was carried out to identify, assess and analyze the extent and rate of land degradation, and determine the relationship among the various classes of terrestrial biomes in Sokoto State Dry Sub-humid agro-ecological zone of northwestern Nigeria. Twelve classes of terrestrial biomes were identified using SI and GIS, and further grouped into land cover, land use and degraded land types. The study showed the alarming scale of land degradation by desert encroachment covering, 1,781,644 ha (55.45 %) at the rate of 1,594.77 ha per annum. Deforestation is occurring at an alarming rate of 3.49 % per annum (194.88 ha). Anthropogenic and natural activities in form of rainfed cultivation, irrigation, deforestation (trees mining), urbanization and perennial/seasonal flooding contributed significantly to desertification and erosion process of land degradation. The loss of forested areas, which is key to sustaining environment is indicated by the negative and significant correlation between anthropogenic activities of rainfed cultivation (r = -0.9306**), irrigation (r = -0.9101*), deforestation (r = -0.9385**) and urban growth (r = -0.8667*). Other relationships assessed through correlation analysis buttress the significant influence between the various terrestrial biomes as drivers of the land degradation threatening Sokoto State. Intensive and intentional effort in planting trees as shelter belts across the state, especially in the desert encroachment areas and erosion sites will greatly combat these environmental degradations. It is also suggested that oil gas can be harnessed as cooking energy to replace or reduce tree mining that causes deforestation.

Key Words: Land Degradation, Terrestrial Biomes. Satellite Imagery, Desert Encroachment and Urban Growth

Nig. J. Soil & Env. Res. Vol. 18: 2019, 32 - 41@ Department of Soil Science, Faculty of Agriculture, Ahmadu Bello University, Zaria, Nigeria

Nigerian

Journal of Soil andEnvironmental Research

activities (Zhang et al., 2014).The severity and extent of soil degredation is increasingin almost all terrestrial biomes and agro-ecologies in arid, dry and even sub-humid areas of the world (Omutoet al., 2014). Its impact seriously affects both the livelihood of the rural poor and urban rich, who depend on natural resources (FAO, 1997; Mailumoet al., 2011; Nkonyaet al., 2016).The causes of land degradation are numerous, interrelated and very complex. However, the immediate cause of land degradation is either natural (example, air pollution from harmattan) or inappropriate land use by humans

INTRODUCTIONLand is fundamental to man's existence, because all the needs of man, such as food, clothing, and shelter are based on land. It is therefore, necessary to take care of land and prevent its degradation. Land degradation is the persistence in decline or loss in biodiversity or ecosystem functions and services due to decrease in productivity and quality of the land that cannot fully recover unaided within decade time scales (Ahmad and Pandey, 2018; IPBES, 2018). This can lead to decline in the biological productivity of land due to climate change and human

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(anthropogenic) through deforestation, overgrazing, bush burning, mining activities among others, thus affecting ecosystem structure and functions, leading to degradation of soil, water, vegetation cover and biological diversity (Ladan, 2004; Nkonyaet al., 2016). Maiangwaet al. (2007) showed the major causes of land degradation in northern Nigeria to include farm vegetation burning, existence of attenuated property rights over land, forest and woodland destruction, overgrazing, increased intensity of farming and contraction of fallows, low-input agriculture, erosion, absence of legislation on land use and absence of a social organizational structure conducive to a sustainable use of land. Land degradation is not eonlycaused by interaction between physical, chemical and biological factors comprising topography, soil properties and climatic features as according to Brady and Weil (2013), but also by human factors and land use management practices (Khaledian et al., 2017). Hence, inappropriate landuse has been considered as one of the causes of land degradation (Biro et al., 2013).Fertile soils are non-renewable resource and their degradation has wide range of consequence on human security for generations to come (Lal, 1994). Land degradation is a severe problem due to which 1.5 billion people are threatened (Nachtergaeleet al., 2010) and about 1.9 billion hectares of land and 250 million people are affected worldwide (Low, 2013). IPBES (2018) recently reported an increasing negative impact to at least 3.2 billion people, with more than 10 per cent of the annual global gross product in loss of biodiversity and ecosystem services.There is an increasing trend in severity of degradation, covering most of the world's land area, which includes 30% forests, 20 % cultivated areas and 10 % grasslands undergoing degradation (Bai and Dent, 2009). Similarly, the annual land degradation due to land use/cover change especially, in Sub-Sahara Africa is on the increase with 22% of the total global cost (Nkonyaet al., 2016).It has been estimated that Nigeria is losing about 351,000 hectares of its landmass to desert conditions annually, estimated to be advancing southwards at the rate of about 0.6 km/ annum. Land degradation therefore, encompasses the whole environment from the surface, underground and above the earth's surface, including soil, water resources, forest (woodland), grasslands, cropland (rainfed and irrigated). About 18% of Nigerian land area is affected by desert encroachment and the effects are portrayed by the vegetation becoming scanty; rivers, streams and lakes drying up; sand dunes forming and reduced yields of crops and livestock (Prudemco Nigeria Limited, 2010). In fact, all the vegetation zones in Nigeria are considered to be in varying stages of vegetation degradation due to the extraction of their wood resources, bush burning, overgrazing and cultivators encroaching into forest and savannahs in the nature of the extensive shifting agricultural landuse practices, infrastructure expansion

and logging.In addition to deforestation, forests are largely affected by degradation. This is primarily due to past and present wood overexploitation, overgrazing, and sometimes overhunting (Croitoru and Sarraf, 2010). These threats are found in the entire country but with different intensities in each forest zone. In Nigeria, most agricultural activities are practiced within the peasant or subsistent level, with unsustainable land management. Such practices are mostly associated with nutrient mining with resultant annual decline in crop yields. Most Nigerian soils are rated low in soil fertility, except the alluvial soils in the floodplains (Ojanuga, 2006). Success in fighting land degradation requires a better understanding of the causes, degree and acquaintance with climate, soil, water, land cover and its potential impact (Oldemanet al.,1991). Land degradation assessment is a primary goal in a decision support system for reversing degradation (Ahmad and Pandey, 2018). Assessment of land degradation on large areas such as state, regional or national level requires going beyond the conventional or ground trothing methods to the use of remote sensing technology. Scientist have developed assessment and monitoring methods of land degradation. These range from expert opinions, field measurements, field observations, land users' opinion, productivity changes, remote sensing and modeling methods among the many approaches (Nkonyaet al., 2016; Mainaet al., 2017; Ahmad and Pandey, 2018).The importance of remote sensing and GIS techniques in mapping and change detection have been highlighted recently by several researchers (Abbas et al. 2010; Lehet al., 2013; Gessesseet al., 2015; Ahmed and Pandey, 2018).Overall, there is a scarcity of information regarding land degradation studies for Sokoto state in the Northwest region of Nigeria. There is also no sufficient quantitative data on current land use practices. Till date, there is no multispectral Land satellite images (Landsat satellite-7& 8 ETM+ and Sentinel 2) that has been applied to assess the changes in landuse land cover features in the area.

Therefore, this study was carried out to assess and analyze

the extent and rate of land degradation, and determine the

relationship between the various forms of landuse and

land cover (biomes) in Sokoto State Dry Savanna of

Nigeria.

MATERIALS AND METHODS

Description of the Study Area

The study is carried out in the entire land area of Sokoto

state in northwestern Nigeria (Figure 1). The State lies

between latitude 11°33ʹ42ʺN and 13°59ʹ7ʺN and

longitude 4°9ʹ36ʺ E and 6°45ʹ33ʺE. It is bordered to the

north by Niger Republic and to the south by Kebbi and

33 Land Degradation Assessment, Using Geospatial Technology in Sokoto State Dry Sub-humid Plain in North-western Nigeria

Zamfara States of Nigeria.The area is situated within the

Dry Sub-Humid plains (Ojanuga, 2006).The climate is characterised by little amount of rainfall throughout the year with mean annual value of 629 mm. The least amount of rainfall occurs in January, while the greatest amount occurs in August. The mean annual temperature is 28.4 °C. The highest mean temperature occurs in April (33.2 °C), while the lowest in January (24.5 °C) (Ojanuga, 2006). Vegetation of the State consists of Acacia Parkland Savanna. Locations within Sokoto Rima and Niger valley and other Upland areas are dominantly EutricArenosols and Chromic Cambisols developed from Sedimentary rocks and Aeolian sand deposits. Floodplains consist of Colluvial- alluvial deposits namely EutricFluvisols and EutricGleysols (Ojanuga, 2006).

Satellite Image and GIS Data

Landsat images were obtained from United States

Geological Survey (USGS) (Landsat 8 TM, ETM) and

Sentinel 2 data from European Space Agency (ESA) for

the more recent time (2010 – 2015)periods. The satellite

image data were processed using Earth Resources Data

Analysis System (ERDAS) image processing software.

Spatial resolution of the satellite Imageries acquired were

between 30 m and 10 m, and the imageries were selected

for the dry season months (November to April). Other

datasets collected and used include drainage network over

each stage at scale 1:250,000 digitized from satellite

imagery, Shuttle Radar Topographic Mission (SRTM)

data which was used to determine landforms and areas

that are perennially and seasonally flooded.In determining the extent of land degradation, the study relied on land-use land-cover changes over the study area. Landsat and Sentinel 2 images for 1990, 1995, 2000, 2005, 2010 and 2015 were clipped in ERDAS imagine 2014 to boundary of SokotoState. The classes of Landuse type include areas under cultivation, irrigation and urban growth. Forested areas, water bodies and rock outcrops were classified under Landcover class type. Land degradation class type includedareas under desert encroachment, dam siltation, deforestation, erosion (especially gullies), perennial/ seasonally flooded arable land and river bed siltation. The images were referenced to the Universal Transverse Mercator (UTM) referencing system with the World Geodetic System (WGS) 84 datum. Images were downloaded, spectrally enhanced and layer stacked and mosaiced for each time period. Each of the images were clipped to the boundary of the state.

Interpretation was done manually delineating the classes according to the interpretation key that has been produced

using the identified spectral properties of target materials.In addition, interpretation was enhanced with SRTM Digital Elevation Modell (SRTM). Digitizing was performed using ArcGIS desktop. Each landuse and landcover class area (Hectares) was calculated and exported as a spreadsheet dataset.

Analysis of Extent of Terrestrial Biomes

The analysed data obtained from GIS interpretation of

satellite imageries were subjected to further analysis to

obtain the total area degraded (equivalent to terrestrial

biome of end-line time; year 2015) and the trend of

degradation from the baseline year 1990 to end-line time

2015 according to the equations developed below by the

authors

Positive value indicates decrease in extent of the

terrestrial biome (TB), while negative value indicated

increasing in extent of TB. The rate of annual change in TB was obtained from the summation of the change in TB for the five years interval in series divided by the 25 years' timeline to obtain an average value considered as the rate of annual TB rate (equation 3).

Tb = Extent of area of terrestrial biome per annum a

(Average annual TB).%Tb Percentage rate of change ofterrestrial biome per a =

annum.The proportion of TB in relation to the entire state was estimated from equation 4.

.

Pearson's correlation analysis was used to determine the

relationship between the different classes of TBs, and the

coefficient of correlation was statistically tested at 5 %

34Maniyunda, L.M. and Ya'u, S. L.

biome between 1990 and 2015 in Sokoto States is

presented in Table 1 and their maps in Figure1 (a, b, c, d, e

and f).

Land cover Terrestrial Biomes

The features identified as terrestrial biome under land

level of significance using Statgraphic Centurion XV

computer soft-ware packages (www.statgraphic.co m., 2005).

RESULTS AND DISCUSSION The spatial extent of the distribution of each terrestrial

35

Figure 1a:Map of Sokoto State showing classes of Terrestrial Biomes (1990 -2005)

Land Degradation Assessment, Using Geospatial Technology in Sokoto State Dry Sub-humid Plain in North-western Nigeria

cover included forest, water body and rock outcrops.

These land cover classes constituted 1.75 % (56,277.98

ha), 0.18 % (5,773.51 ha) and 1.52 % (48,840.53 ha) of the

land area in Sokoto State respectively. The State is situated

in Dry Sub-humid agro-ecological zone and is prone to

desertification, and the study indicated that forested area

reduces more rapidly at the rate of 1,887.46 ha (3.35 %;

Table 2) per annum. The decrease in forest area may also

be attributed to anthropogenic activities of trees mining

without replacement, urban growth, rainfed and irrigated

crop production, animal uncontrollable grazing, as well as

desert encroachment. This was indicated by the significant

negative correlation between the various stated land uses

and forested areas (Table 3).

However, rock outcrops and water body change slightly

and irregularly within the period of the study. There was

inconsistent decrease in water body at the rate of 11.93 ha

per annum (0.21 %) and may be attributed to climate

change resulting in season variation in rainfall but with

decreasing pattern (Zhang et al., 2014; Van der Eschet al.,

2017). The conversion of forest to other land uses have

been strongly attributed by several authors to the increase

in population (Ladan, 2004; Abbas et al., 2010), as

indicated by the anthropogenic activities in this study.

Landuse Terrestrial Biomes

Areas under rainfed cultivation, irrigation project and

urban growth as land use type of terrestrial biomes were

estimated to cover 957,589.57 ha, 1,862.48 ha and

12,045.08 ha respectively in Sokoto State at the end of the

study time line in the year 2015. Areas for the three (3) land

uses increased consistently for the 25 years at the rate of

0.16% (1497.55 ha), 1.36 % (25.37 ha) and 1.07 % (128.61

ha) per annum, respectively.

Area under rainfed cultivation was second to desert

encroachment in the State, and was similarly reported by

Foley, et al. (2011). The consistent increase in land area for

rainfed cultivation at the rate of 1,497.55 ha (0.16 % per

annum; Table 2) is below the 4 % increase rate reported in

Sub-Sahara Africa (SSA), as the largest increase in the

world (FAOSTAT, 2014), and may be due to increasing

awareness on sustainable soil management and deviation

from shifting cultivation to other cropping system such as

crop rotation, agro-forestry and mixed cropping.

Figure 1b:Map of Sokoto State showing classes of Terrestrial Biomes (2010 -2015)


37 Land Degradation Assessment, Using Geospatial Technology In Sokoto State Dry Sub-humid Plain in North-western Nigeria

Table 1: Spatial Distribution of Terrestrial Biomes of Sokoto State (1990 - 2015)

COED Class 1990 1995 2000 2005 2010 2015 Grand TotalAreas under cultivation 919,573.03 931,080.52 930,897.17 935,576.76 953,589.57 957,011.78 5,627,728.83

Areas under desert encroachment

1,741,774.97

1,752,232.36

1,751,325.42 1,759,467.23

1,777,475.24 1,781,644.25 10,563,919.47

Dam siltation

17,429.25

13,534.26

15,965.07

11,847.46

9,780.62 7,732.83 76,289.50

Deforested Area

717.04

1,712.30

2,775.41

3,183.04

4,085.08 5,588.95 18,061.82

Eroded areas especially gullies

101,122.92

104,234.74

106,098.04

105,702.33

109,917.60 111,286.93 638,362.56

Forested Area

103,464.53

78,511.78

75,686.53

75,660.36

63,867.57 56,277.98 453,468.76

Irrigation project

1,228.22

1,483.61

1,473.99

1,486.44

1,521.69 1,862.48 9,056.43

Perennial/seasonally flooded arable lands

255,148.49

247,037.18

252,379.80

245,366.83

219,981.50 219,459.90 1,439,373.69

River Bed Siltation

3,497.20

3,711.30

3,570.17

2,554.66

5,395.06 5,471.96 24,200.34

Rock outcrop

52,848.04

51,981.31

53,789.78

55,566.93

50,425.77 48,840.53 313,452.35

Urban growth

8,829.87

9,365.92

9,386.90

9,526.35

10,945.46 12,045.08 60,099.58

Water Body

6,071.80

6,976.81

5,999.27

5,813.33

6,070.59 5,773.51 36,705.31

Grand Total

3,211,705.36

3,201,862.08

3,209,347.55

3,211,751.71

3,213,055.75 3,212,996.18 19,260,718.63

Table 2 Total, Mean Proportions and rate of change of the Terrestrial Biomes ,

Class Total Terrestrial

Biomes Area (ha)

Proportion of Total

Terrestrial Biomes Area

(%)

Terrestrial Biomes Area (ha) within 25 years (1990 –

2015)

Terrestrial Biomes Area (ha) within

25 years

(1990 –

2015)

Average Terrestrial Biomes Area (ha)

per Annum

Rate of annual change in Terrestrial Biomes

Area (%)

Area under Cultivation

957011.8

29.79

37438.7

37438.7

1497.55 0.16

Area under Desert Encroachment

1781644

55.45

39869.3

39869.3

1594.77 0.09

Dam Siltation 7732.829

0.24

9696.419

9696.419

387.857 5.02

Deforested Area 5588.949

0.17

4871.91

4871.91

194.876 3.49

Eroded Areas Especially Gullies

111286.9

3.46

10164

10164

406.56 0.37

Forested Area 56277.98

1.75

47186.55

47186.55

1887.462 3.35

Irrigation Project

1862.48

0.06

634.257

634.257

25.37 1.36

Perennial/Seasonal Flooded Arable Lands

219459.9

6.83

35688.58

35688.58

1427.543 0.65

River Bed Siltation 5471.956 0.17 1974.76 1974.76 78.99 1.44

Rock Outcrop 48840.53 1.52 4007.505 4007.505 160.3 0.33

Urban Growth 12045.08 0.37 3215.2 3215.2 128.608 1.07

Water Body 5773.513 0.18 298.286 298.286 11.931 0.21

Total 3212996 100.00

Figure 2 Proportion of Total Terrestrial Biomes of Sokoto State at study end-line (2015)

Table 3: Correlation Matrix of BiomesClasses of Terrestrial Biomes

Areas under cultivation


Dam siltation

Deforested Area


Forested Area

Irrigation project

Perennial/seasonally flooded area

River Bed Siltation

Rock outcrop

Urban growth


0.9972***

Dam siltation -0.9538**

-0.9640** Deforested Area 0.9485** 0.9471**

-0.9088*


0.9783***

0.9661**

-0.9007*

0.9740**

Forested Area -0.9306**

-0.9109*

0.8939*

-0.9385**

-0.9643**

Irrigation project 0.8548* 0.8443*

-0.8665*

0.9182**

0.8815*

-0.9101*

Perennial/seasonally flooded area

-0.9754***

-0.9792***

0.9293**

-0.8721*

-0.9164*

0.8340*

-0.7681NS

River Bed Siltation 0.8052 NS 0.7893

NS

-0.6651

NS

0.6687

NS

0.7653

NS

-0.6408

NS

0.6236

NS

-0.8709*

Rock outcrop -0.6992 NS

-0.6864

NS

0.6137

NS

-0.5599

NS

-0.6366

NS

0.5361

NS

-0.6233

NS

0.7838

NS

-0.9528**

Urban growth 0.9630** 0.9634**

-0.9170*

0.9380**

0.9409**

-0.8667*

0.8969*

-0.9537**

0.8549*

-0.8024

NS

Water Body -0.3391 NS -0.3731 NS 0.2744 NS -0.5208 NS -0.3928 NS 0.2371 NS -0.2690 NS 0.2912

NS

-0.1202

NS

-0.0362

NS -0.3810 NS

Level of significance (LOS)(P): NS = not significant, * < 0.05, ** < 0.01, *** P <0.001



The significant correlation (Table 3) between the land use classes indicated that the increasing areas of these terrestrial biomes were significantly influenced by the same factor and is attributed strongly to the increase in population and anthropogenic activities to meet human needs (Abbas et al., 2010; Omutoet al., 2014). This pressure will continue to increase with the demand for more food to feed the increasing population and the need for food security of the nation. This has influenced opening of more land for irrigation projects within the State.Jibrinet al. (2008) attributed more hectare cultivation to the awareness of successful productivity under irrigation projectsagainst the challenge of climate change.Urban growth is an index of increase in population of any community (Mainaet al., 2017) and the present study showed a consistent increase in urban growth. The annual rate of urbanization was recorded as 1.07 % (128.61 ha). Urbanization has a direct or indirect impact on other land use, land cover and land degradation classes (Mainaet al., 2017). The correlation matrix in Table 3 showed significant positive relationship between urban growth with rainfed cultivation (r = 0.9630**), irrigation projects (r = 0.8969*), desert encroachment (r = 0.9634**), deforestation (r = 0.9380**), river bed siltation (r = 0.8549*) and erosion (r = 0.9409**). This implies that increase in urban area or population will increase the terrestrial biomes that had significant correlation with urban growth. This is in agreement with the report of Abbas et al. (2010) that increasing population and economic activities put pressure on available land resources.

Land Degradation ClassesIn Sokoto State, the most threatening class of land degradation is desert encroachment, covering 55.45 % (Figure 2)(1,781,644.25 ha) of the land area. Desert encroachment increased consistently during the period of the study at the rate of 0.09 % per annum and equivalent to 1,594.77 ha. This implies that significant proportion of the state's land resources has been lost to desertification within the Dry Sub-humid agro-ecological zone of northwestern Nigeria. The analysed satellite imagery data indicated 39,869.3 ha was lost to desertification between the year 1990 and 2015. From the correlation analysis, anthropogenic activities such as rainfed and irrigated cultivation, deforestation, erosion and urbanization significantly related positively with desert encroachment (Table 3). Similarly, there was highly significant correlation between desert encroachment with erosion (r = 0.9661**), thus implying that both natural and anthropogenic activities significantly contribute to desertification (Ladan, 2004). Significant but negative correlation was observed between forested areas and desert encroachment (r =-0.9306**) which implies that increase in tree plantation will significantly reduce

desertification process (Prudemco Nigeria Limited, 2010).Areas associated with deforestation as a land degradation terrestrial biomeconsistently increased at the rate of 3.49 % (194.88 ha) per annum, and similar to the national level of 3.3 % (Butler, 2005), which is regarded as the highest deforestation rate. It may be due to cutting down of trees for fuel energy and livestock feeding(green leaves) without replacement (Prudemco Nigeria Limited, 2010). The total area deforested till 2015 is accounted for as 5,588.95 ha (0.17 %) of the entire land in Sokoto State. Deforestation reduces soil organic matter which contributes to improvement in soil nutrients, cation exchange capacity and binding of soil particles thus conserving soil from erosion menace (Brady and Weil, 2013). Prudemco Nigeria Limited (2010) reported deforestation as a major contributor to erosion in northern Nigeria, as it reduces the effect of shelter belt serving as wind breakers. Therefore, it is suggested that Nigerian oil gas lost through flaring can be converted to cooking energy and be supplied at affordable price to reduce tree mining.Analysis of the satellite imagery showed that eroded areas covered 111,286.9 ha of the State, and annual erosion was recorded at the rate of 406.56 ha (0.37 %). Land loss to erosion consistently increase throughout the period of study. This may be attributed to increasing anthropogenic activities influencing erosion and climate change. This is buttressed by the significant correlation between erosion and rainfed cultivation (r = 0.9783***), deforestation (r = 0.9485**), irrigation (r = 0.8548*) and urban growth (r = 0.9630**). Intentional effort is required to plant trees and other vegetation to serve as soil cover against rain impact on erosion. This is clearly indicated by the highly significant and negative correlation between forested area and erosion (r = -0.9643**).Perennial/seasonal flooded arable lands were third in order of ranking by size of terrestrial biomes covering 219,459.9 1,769,757.47 ha of the entire state. The annually rate of perennial/seasonal flooding was analysed as 1,427.54 ha (0.65 %). Perennial and seasonal flooding has caused great loss of crops such as rice and homes within floodplains.The seasonal variation in trend of flooding in relation to other terrestrial biomes were negatively correlated except for dam siltation (r= 0.9293**). Hence, the key factors probably contributing to flooding may be natural phenomenon such as climate change rather than anthropogenic activities. The proportion of areas covered by river bed and dam siltation was similar, and was estimated as 0.17 % each. The rate of siltation in both dam and river bed was irregular and tend to be influenced by erosion pattern, though the annual rate of siltation was calculated as5.02 % and 1.44 % for dam and river bed respectively. Hence agricultural activities within the basin of the dam and rivers catchment areas may contribute to erosion of soil

40

and same deposited as sediments in river bed and dams.

CONCLUSION

The use of satellite imagery and geographic information system contributed to the identification and assessment of the terrestrial biomes covering Sokoto State. Twelve classes of terrestrial biomes were identified and further grouped into land cover, land use and degraded land types. The study showed the alarming scale of land degradation by desert encroachment, covering 1,781,644 ha (55.45 %) the State. Anthropogenic and natural activities in form of rainfed cultivation, irrigation, deforestation (trees mining), urbanization and perennial/seasonal flooding contributed significantly to desertification and erosion processes of land degradation. Correlation statistics buttressed the strength of the association between the various terrestrial biomes as drivers of the land degradation, threatening the State.

Intensive and intentional effort in planting trees as shelter

belts across the state, especially in the desert

encroachment areas and erosion sites and sustainable

agricultural practices will greatly combat these

environmental degradations. The study also suggested that

Nigerian gas, lost through flaring, can be converted to

cooking energy and supplied at affordable price to reduce

tree mining,minimizing deforestation.

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Land Degradation Assessment, Using Geospatial Technology