GIS-based land degradation risk assessment of Damietta governorate, Egypt

This study aims to assess the land degradation risk in the governorate by using Geographical Information System (GIS) technique. The preliminary landforms of the area were defined by using remote sensing data. The area includes flood plain, lacustrine plain and marine plain. A total of 18 soil profiles representing different mapping units were studied. Thirty six soil samples were collected for laboratory analysis. The soil properties of bulk density and electrical conductivity (EC) were attached to the different landforms. The thematic layers of these properties were created in Arc-GIS 10.2 software using the spatial analysis function and then these layers were matched together to assess the soil degradation. The obtained results revealed that the high risk of physical (i.e. soil compaction) and chemical vulnerability (i.e. salinization) covered an area of 86.02 km^2 (12.83%) and 2.28 km^2 (0.34%), respectively in the surface soil layers. The land degradation hazard in the surface layers due to soil compaction was moderate to very high, whereas the degree of salinization was low to high. Regarding to the subsurface soil layers, the high risk of physical degradation and chemical degradation covered an area of 127.8 km^2 (19.06%) and 10.6 km^2 (1.58%), respectively. The land degradation hazard due to soil compaction in the subsurface layers was moderate to high, whereas the degree of salinization was low to very high.