LAND SUITABILITY EVALUATION FOR REDUCING SOIL LOSSES IN KAHRAMANMARAS, TURKEY

摘要

To indicate the effect of land evaluation in reducing erosion, the amount of soil loss developed under the conditions of current land use was compared with those under suitable land use in Karacasu district of Kahramanmaras. To compute soil losses, the method of Universal Soil Loss Equation integrated with Geographic Information Systems techniques have been implemented. First, the classification of land suitability was performed according to the Framework for Land Evaluation of Food and Agriculture Organization. In the process of determining land suitability, not only physical suitability assessment but also economic and environmental assessments were performed. The soil loss was estimated according to Universal Soil Loss Equation for both current and suitable land use conditions. The Universal Soil Loss Equation parameters included rainfall erosion factor, soil erodibility factor, topographic factor derived from digital elevation model, cover-management factor, and support practice factor. The raster layers with the pixel size of 30 meters were generated for each parameter using Geographic Information Systems tools. Cover-management factor and support practice factor factors were evaluated while other factors remained constant for both conditions. The cover-management factor for current land use type) and for suitable land use type) were determined using digital image processing methods and the classification of land suitability, respectively. The support practice factor was determined based on the traditional erosion practices for each individual land use type. The results indicated that suitable land use type was the primary factor that reduced soil losses by approximately 64% in the study area. The irrigated agricultural areas were more suitable for irrigated orchard usage, while dry farming and rangeland areas were more suitable for forest usage.