The use of RS and GIS for Assessment of Wadi El- Assiuty Soils, Egypt

The current study area is part of Wadi El- Assiuty, Assiut, Egypt. It is one of the most promising developed areas in Egypt. It lies in the eastern desert of Assiut city. It is located between longitudes 31°18' and 31°48' E and latitudes 27°10' and 27°45' N. The study aims to generating a semi-detailed soil map that is suitable to achieve a land capability evaluation of Wadi El- Assiuty soils using "ILWIS"-GIS.
Visual interpretation was first undertaken on an enhanced natural color composite landsat TM image and overlaid on Digital Elevation Model (DEM) for the preparing of geo-pedological soil map using the 3D GIS capabilities. The mapping units of the study area were strictly verified in the field where19 soil profiles were selected to represent the different mapping units. The soil profiles were carefully described and representative the soil samples were taken from each profile. Then, the main physical and chemical characteristics of the different mapping units were determined and stored into "ILWIS"-GIS database. The soils were classified up to the sub group level according to the protocol of the United States Department of Agriculture (USDA Soil Taxonomy, 2014a). The main soil sub groups that were investigated in the study area were; Typic Haplocalcids and Typic Haplosalids.
California Storie index, (Storie, 1978) and O'Geen etal. (2008) are used to rate the soil capability for intensive irrigated agriculture. The results were displayed as maps using "ILWIS"-GIS.
Results indicated that the area currently lacks the high capability class. However, three soil capability classes of C2, C3 and C4 were recognized in the study area. About 32493.60 feddans (29.9% of the evaluated soils) are moderately capable, 73387.14 feddans (67.3%) are marginally capable and 3156.26 feddans (2.9%) indicating limited capability. A potential capability map was also produced after eliminating the correctable limitations, by improving the soil properties some of these soils can approach potential capability. The results show that 67.3% of the total study area is potentially suitable for agriculture.
From this study, it is recommended to improve the current capability of the studied soils by applying soil management practices that include:
-  Adding organic and chemical fertilizers to improve moisture availability, nutrient availability and CEC.
-  Executing a leaching process for removing the excess of soluble salts.
-  Using modern irrigation systems to reduce the irrigation periods to avoid salts accumulation and the formation of soil crust in the calcareous soils.