Physico-Chemical Characterization of Water and Soil of the M’nasra region in the Gharb plain (Northwest Morocco)

Abstract

The aim of this work is to carry out an evaluation of the quality of agricultural soils and water in the irrigated area of the M’nsara region in the Gharb plain (Northwest Morocco) with the goal of describing the degree of degradation of natural resources and improve the sustainability of the environment and irrigated farming systems of the region through optimal management of these resources. Eighteen water and nineteen soil samples were collected based on existing soil and piezometric maps of the irrigated areas, distributed into 3 different zones: A, B, and C. Characterizations of the main parameters of soil and irrigation water quality were made. Irrigation water salinity varies between 0.5 and 1.3 dS/m. The irrigated soils from the groundwater have shown a secondary salinization superior to that of irrigated soils by the waters of the dam. Cultivated soils present a salinity that reaches 1.90 dS/m in some areas. The results show that 68.4% of the soil samples are poor to moderately poor in organic matter. The sodium adsorption ratio (SAR) shows a minimal risk to accumulate sodium in the soil with 16.7% is slightly alkaline. The soils are weakly to moderately basic and represent respectively 73.7 and 10.5 % of the study area. Potassium and available phosphorus have very low values in the majority of soils which will have a negative impact on the environment. The spatialization of these parameters was performed by the determinsitc method of inverse distance weighted (IDW). In order to delineate areas that are a priori subject to environmental degradation in order to understand the effect of agricultural intensification on the sustainability of natural resources, taking into account the type of management water irrigation in the arid region.