Geostatistical Modelling of Soil Physicochemical Variability for Improved Irrigation Management in B´eni-Amir, Morocco

Abstract

Irrigated areas in Morocco are increasingly affected by climate change and the intensification of agricultural practices, particularly in arid and semi-arid zones. The Beni-Amir irrigation area, located in the Tadla plain (central Morocco), illustrates this degradation dynamic. This study analyzes the spatiotemporal variability of certain physicochemical properties of the soil at a depth of 0 to 20 cm, in particular organic matter (MO) (2015 and 2019), pH, and electrical conductivity (EC) (2013 and 2023), as indicators of soil quality. The geostatistical approach is an innovative method that allows data to be estimated taking into account their spatial dependence and uncertainty. The results show a moderate increase in organic matter content, from 2.89% (2015) to 3.58% (2019). The pH increased slightly to 8.32 in 2023, reflecting a trend towards alkalization. Electrical conductivity increased significantly, from 1.56 dS/m (2013) to 8.14 dS/m (2023), indicating an advanced process of salinization. The maps obtained by geostatistical interpolation reveal strong spatial heterogeneity, with localized areas of high salinity, particularly in the east and southeast of the perimeter. The spatial distributions of pH and organic matter also highlight different dynamics depending on the intensity of agricultural practices. These results highlight the combined effects of anthropogenic pressures and climatic hazards on soil quality in Beni-Amir. The sustainability of agricultural systems in this context depends on integrated and spatialized management of soil and water resources, the implementation of appropriate crop rotations, and targeted soil conservation and rehabilitation strategies.