Study of the situation of soils around the sabkha of Sed el Masjoune

(Central Bahira - Kalaa des Sraghna, Morocco)

Faculté des sciences Rabat

Soukaina EL HASINI 1, Abdlamjid ZOUAHRI 2, Houria DAKKAK 2, Ahmed DOUAIK2, Mohamed EL AZZOUZI 1

1Department of Chemistry, Faculty of Sciences, BP 1014, Rabat-Morocco2UR Environment and Conservation of Natural Resources, INRA, CRRA Rabat, BP 6356 Rabat Institute, Morocco

Introduction

In Morocco, the surface area of saline soils rises to more than 700,000 hectares

throughout the country, of which 10,000 hectares are concentrated in the Sed El

Masjoune region (El Khadir. M et al, 2013).

The sabkha of Sed Al Masjoune constitute the closed depression of the Bahira plain

where accumulate the run-off water descending from the neighboring reliefs

(Karroum, 2014). The arid climate, topographic properties as well as agricultural

practices present the mean factors defining the quality of soils in this region.

How’s the current situation of soils quality, and what’s the effect of agricultural

practices on soil texture?

Soil sodicity:

Sodium can explain only 35% of soil salinity, which is

confirmed by the distribution of ESP. therefore, the

problem of sodicity found to be minor.

ECp

Regarding ECp, Soils are highly variable

(CV=155%). 43 % of soils found to be non-saline,

but the total of 47% was shared between the different

levels of salinity.

The combinate use of manure and fertilizer decrease the percentage of clay as the

same level of that of non-agricultural soil.

The use of fertilizer alone declines the quantity of silt in soil and remain the quantity

of lime as the non-agricultural soil.

There is no effect of amendments on the percentage of sand.

ConclusionThe situation of soils around the sabkha of Sed el Mesjoune

is inadequate generally for crops production, under the

effect of environmental conditions and agricultural

practices, which require careful management for sustainable

and environmentally friendly agriculture

Bibliography

EL Khadir.M, EL Allam.M, Zouahri.A (2013) « Evaluation de la tolerence à la salinité d’arbres et d’arbustes pour la valorisation des terres marginales et eaux salines », Research Unit on the

Environment and Conservation of Natural Resources-CRRA Rabat - I.N.R.A – Maroc.

Karroum M, El Mandour A, Khattach D, Cassas, Himi M, Rochdane S, Laftouhi N, Khalil N (2014) «Fonctionnement hydrogéologique du bassin de la Bahira (Maroc central) : apport de

l’analyse des données géologiques et gravimétriques», Canadian Journal of Earth Sciences, Vol. 51, N° 5 : pages 517-526

Method

The soil samples were taken using a manual auger at a depth of (0-20 cm), dried and

sieved.

The parameters analyzed were: electrical conductivity of saturated paste (CEp),

organic matter (OM), assimilable phosphorus (P2O5) and exchangeable potassium

(K2O), in addition to soil granulometry.

Analysis and results

43%

11%

18%

6%

23%

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

<4 4_8 8_16 16_32 >32

% o

f si

tes

ECp (mS/cm)

The conductivity

y = 0.2523x + 2.2455R² = 0.3534

0

20

40

60

80

100

120

0 20 40 60 80 100 120 140 160 180

Na+

(meq

/100

g)

EC (mS/cm)

Effect of agricultural inputs on soil texture:

P2O5

The phosphorus abundance varies widely

among sites (CV=180%), only that 55% of

sites have a high to very high phosphorus

content

17%

13%15%

28% 27%

0%

5%

10%

15%

20%

25%

30%

P2O5<15 15<P2O5<30 30<P2O5<45 45<P2O5<100 P2O5>100

% o

f si

tes

P2O5 (ppm)

Distribution of the phosphorus

OM

The results show that the majority of soils

are poor to moderately poor in organic

matter. This requires the use of organic

inputs as an amendment to improve the

degraded condition of these soils.

31%

32%

31%

5%

1%

distribution of organic matter

MO(%)<0,7 0,7<MO(%)<1,5 1,5<MO(%)<3 3<MO(%)<6 MO(%)>6

K2O

The results of the studied samples show that 78% of

the soils are very rich in potassium, this excess can

be due to the poor management of fertilization in this

zone.0%

6%

3%

13%

78%

K2O<60

60≤K2O<100

100≤K2O<180

180≤K2O<300

K2O>300

% of sites

K2

O (

pp

m)

Distribution of potassium

Clay % Silt % Sand % Lime %

Fertilizer (38,9 ± 7,3) a (17,2 ± 5,6) d (43,9 ± 8,3) a (13,1 ± 7,9) a

Manure (33,6 ± 10,4) ab (22,4 ± 6,4) c (44,1 ± 9,5) a (4,9 ± 5,6) b

Manure and Fertilizer (27,5 ± 9,3) b (28,9 ± 13,7) a (43,5 ± 13,4) a (5,9 ± 6,2) b

Neither manure nor fertilizer (37,8 ± 13,4) a (23,7 ± 6,9) cb (38,4 ± 16,2) a (6,7 ± 7,2) b

Non-agricultural soil (28,5 ± 9,6) b (27,7 ± 7,7) ab (43,8 ± 10,5) a (15,7± 10,4) a