Land Capability of Some Soils Representing Western Limestone Plateau at Assiut

This study aims to evaluate the land capability of some soils located on the western limestone plateau, Assiut governorate, Egypt. The study area is bounded by longitudes 30^◦ 37^′ 00^″ and 31^◦ 17^′ 00^″ E and latitudes 26^◦ 48^′ 00^″ and 27^◦ 38^′ 00^″ N. Nineteen soil profiles were selected to represent the soils of the study area using the topography status and the surface field observations.
The elevation of the studied area varied from 116 to 283 m above the sea level. The studied soil profiles showed mainly sand, sandy loam and loamy sand texture with different gravel contents. They were shallow to deep. The soil organic matter content was low and decreased with depth. The studied soils ranged from non-saline to very strongly saline with EC_e values that varied from 1.7 to 89.7 dS/m. They were moderately alkaline to very strongly alkaline as the soil pH ranged from 7.9 to 9.3. The calcium carbonate content of these soils varied from 13.1 to 89.4% with a calcareous parent material while the gypsum content was low (0.02-3.03%). Low values of the cation exchange capacity (CEC) were recorded for these soils reflecting their coarse texture. Most of the studied soils are non-sodic, with an ESP value less than 15%.
The land capability of these soils was achieved using both the modified Storie index and the applied system of land evaluation (ASLE) program for arid and semi-arid regions. The rating of the studied soil profiles according to modified Storie index was between 13.0 and 50.0% (grade 3 to grade 5) that ranged from fair for agricultural use to non-use for agriculture. Moreover, these soil profiles showed an ASLE rating that varied from 4.9 to 26.6% (class 4 to class 6). According to this program, the studied soils ranged from poor for agricultural use to non suitable for agriculture. The main limitations for these soils were the soil texture, calcium carbonate and salinity.