Impact of land use changes on soil resources degradation in southern Rif Central, Morocco

Abstract

In the Central Rif in the north of Morocco, forest ecosystems have suffered a very sharp decline in favor of crops. The installation of agriculture at the expense of forests illustrates the important roles of forests on the environmental, economic and social levels. The objective of this work is to assess and quantify the impact of land-use change on land degradation in the southern Central Rif. The loss of fertility of cleared soils was assessed using physico-chemical analyses after 2, 6, 10 and 22 years of cultivation. A manual rainfall simulation was used to assess the impact of clearing followed by cultivation on the hydrodynamic behavior of the soil. The results show that the conversion of forests into agricultural areas has multiple consequences on the natural system. The soil becomes unstable under the effects of successive ploughing which leads to a significant reduction in soil reserves; organic matter decreased by 73% of its initial content and the nitrogen rate decreased by -62.5%, acidity increased by one unit after 22 years of cultivation. Soil losses were estimated at 1126,8 g m^-2 h^-1 for a precipitation sequence of 80 mm h^-1 for 45 minutes. This degradation hinders agricultural productivity, leading farmers to abandon the land and seek new plots at the expense of forests to meet their agricultural land needs.

Keywords: Land use, Soil reserves, Water erosion, Central Rif, Morocco