Investigation of soil surface indicators and rangeland functional attributes by grazing intensity and land cultivation (case study: Orazan Taleghan)

Management activities like grazing intensity and land cultivation effects rangelands characteristic. For sustainable utilization of rangeland, information of changes is required. Soil surface indicators and functional attributes help to judging about management impact. So for investigation on these activities effects in semi arid rangeland, one vegetation community was selected in Taleghan region. Five cases including: three grazing intensities (heavy, moderate and low), recently cultivated and relict areas that were cultivated in last two decades were assessed. Landscape function analysis (LFA) method was used to evaluate management effects on soil surface characteristics and rangeland functional attributes. In this method for determination of three functional attributes of stability, infiltration and nutrient cycle, 11 soil surface indicators were considered. They are soil surface cover (soil protection from erosion), perennial canopy/basal cover, litter (cover, origin, degree of decomposition), cryptogam cover, crust brokenness, type and severity of erosion, deposited material, soil surface roughness, soil surface resistance to distribution, slake test (soil stability test) and texture. Based on the results, land cultivation reduced functional attributes. By increasing grazing intensity, palatable species are eliminated and in heavy grazing area the dominated vegetation cover are annuals. Vegetation and soil surface layer degradation increased soil erosion, created gully and reduced functional attributes. In relict area because of re-establishing homogenous annuals, soil indicators and functional attribute were improved.