Assessment of the Quality of Soil and Groundwater of the Agricultural Area of Sidi Yahya Region, Morocco

Abstract

The Gharb plain is the largest agricultural area in Morocco. It is characterized by fertile soils and the availability of water either from surface or groundwater which allowed intensive agriculture. The aim of this research work is to study the impact of this land management on the quality of water and soil. The study was done for the irrigated perimeter of Sidi Yahya belonging to the province of Sidi Slimane, Gharb (Morocco). Depth of water table and water pH were measured in situ while water and soil samples were collected and brought to the laboratory for their physico-chemical analyses. Sampling of 33water wells and soil samples, from six different zones, was done between May and October 2018. Analysis of variance (ANOVA) was used to check if mean water and soil parameters differed between zones. The results showed that the minimal and maximal water table depth were 6 and 96 m, respectively. Also, slightly more than half of the wells (51.5%) were inadequate for irrigation since they were either highly or extremely saline. Furthermore, soils were poor to moderately poor in organic matter but very rich in potassium and the phosphorus content was highly variable. Based on the statistical analysis, it is clear that the six zones had significantly different means for CaCO3, pH, OM, and exchangeable sodium percentage. Soil degradation like pollution and salinization may occur in this region if poor quality water is used for irrigation and if land is mismanaged. This research work can be considered as a first step towards a program for monitoring the quality of soil and water for adapting the land management with the final objective of securing high productivity and sustainable use of soil and water resources.