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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