Erosion risk associated with rapid and extensive agricultural clearances on dispersive materials in southeast Spain

Abstract

This research explores the socio-economic, climatic and lithological components of the contemporary erosion problems in the Sorbas area of Almeria, Spain, and devises a mapping schedule to describe the particular risks associated with the large-scale clearance of dispersive soils for arboriculture. The paper firstly tracks the pace of the agricultural change across this sensitive landscape using provincial agricultural statistics. Secondly, the elements of geomorphological sensitivity in a 70 km2 study area southwest of Sorbas are considered. Previous work has suggested that dispersive properties of local lithologies are important risk-associated variables alongside vegetation cover and topography. A method whereby all these factors can be included in the assessment of the degree of erosion risk is developed. Using repeat NERC air photography for 1996 and 2001 as a basis, aerial photomosaics of the study area are compared, producing a map of land-use change between 1996 and 2001. With this map as a basis, the risk-mapping schedule is piloted for a sub-study area on newly cleared land. The sustainable management of these extensive changes is discussed in a final section. It is argued that the proposed algorithm for erosion risk mapping could facilitate the management of existing agricultural clearances, and the siting of new developments to minimise soil loss.