干旱区生态环境知识资源中心

The catchments of the Beni Said territory, at the semi-arid eastern end of the Rif mountains, have been experiencing a major environmental and agricultural crisis since the beginning of the 1980s. The state of severe degradation of the slopes due to gullying, the permanent moisture deficit in the soils and the devastating force of wadi floods are the consequence of an environment affected by rill wash and subjected to intensified mechanical erosion. This dynamics is highlighted not only by landscapes, but also by erosion pins placed in several gullies and the monitoring of several wadis between 1999 and 2001. This situation is not only due to the physical and historical past, but also to a combination of recent climatic and human impacts affecting cultural practices and land use. Here, an overview of the situation is presented, and monitoring and quantification of the human impact are based on the measurement of rill wash and soil loss on test plots. The results show that fallow land appears to be the land use category most susceptible to erosion and that expansion towards fallow areas of sites already degraded by erosion occurs through the growth of erosional landforms that were initiated during the first year after cultivation has ceased. This highlights the negative, qualitative and quantitative effects of recent changes affecting land use and cultural practices on the stability of the environment.