Comparison of soil degradation in the surface and depth layer in different land use

Soil quality are defined as the capacity of soil to function as a vital living system within land use boundaries. This function which sustains biological productivity of soil also maintains the quality of surrounding environment and human health. The aim of this study was to soil degradation in the surface and depth layer in different land use in Shabestar catchment. A map of the area, including soil maps and land use, was obtained from the GIS. The selected land use included agricultural land, gardens, barren lands, and rangelands. Soil samples were taken in every part of the area, including agricultural land, and soil factors were measured within two groups of (a) soil improvement factors, including nitrogen, phosphorus, potassium, humus and lime, and (b) soil degradation factors, including acidity, sodium adsorption ratio (SAR), chlorine, sodium, bicarbonate and salinity, in two depths of 0-30 and 30-60 cm. The results obtained in T-test showed that, in most treatments, the deep layers of the soil have been destroyed and have contributed to desertification. It is due to the accumulation of sodium and sodium adsorption ratio in this layer, while the damaging effect has been low in the surface layer. This is the reason why it can be seen in farmland irrigation.