Human-induced impacts of land use management on soil properties(case study: high-altitude area of Sahand mountain rangelands East Azerbaijan-Iran) ,

ABSTRACT: Dry cultivation and overgrazing are widely recognized as the degradation primary causes of high land rangelands in semi-arid regions of Iran. The objective of this study was to quantitatively evaluate the magnitude of changes in soil properties due to long time of dry cultivation with Wheat (DCW), dry cultivation with Medicago (DCM), recently abounded cultivation (RAC), and finally grazing Land (GL) in an ecosystem of the semi-arid high lands in Sahand Mountain, Iran. In order to this, after sampling of surface soil in each four sites, soil parameters such as pH, EC, bulk density (BD), soil organic matter (SOM), total nitrogen (TN), available K, P, soil moisture (SM) and soil particles (clay, silt and sand) were measured in laboratory. ANOVA analysis showed that the historical conversion of land-use from native vegetation (GL) to dry cultivation resulted in sharp declines in SOM, TN, P, K, and EC and increase in pH. Cultivation abandoned (RAC) have decreased of SOM, TN, P, K, EC, SM but pH and BD have increased in RAC comparing with both cultivation land. Cultivation of Medicago has promoted soil quality indices such as nutrient elements and physical properties compared to the wheat cultivation. The results address the importance of grazing land for maintaining soil quality properties on the landscape. From the perspective of soil resource management and environmental conservation, a viable option for these fragile high-altitude rangelands would be to stop conversion of rangeland to dry cultivation and adopt moderate grazing intensity practices to limit overgrazing. Also, the abounded dry cultivated areas should be converted back into native rangeland.