Evaluation effects of Tree and shrub species(ziziphus spina cristi, ziziphus numolaria and Astragalus fasciculifolius) on the Soil Surface Indices in Winter Rangelands (case Study: Khashab Stream Rangelands, Southern Kohgiluyeh and Boyerahmad)

Evaluation of important characteristics of soil and vegetation can inform us of the potentials of rangelands and determine the range condition. Soil surface characteristics directly affect vegetation. On the other hand, factors such as plant species, vegetative form and density affect soil characteristics. Therefore, this study was aimed to evaluate the effects of woody plants on soil characteristics using rangelands soil classification method (SSCC) in Khashab rangelands. Eleven soil surface indices within the plant patches of Ziziphus spina cristi and Ziziphus nummularia and Astragalus fasciculifolius as well as a mixture of trees and shrubs (Ziziphus spina cristi Ziziphus nummularia) and interpatches (bare soil litter) were measured along three transects of 70 m in five replicates. Then the factors measured in terms of three indices of stability, infiltration and nutrient cycling for each patch were classified. The results showed significant differences for stability index among the study patches, so that Ziziphus spina cristi Ziziphus nummularia could improve soil stability. Infiltration index did not show significant difference between Ziziphus nummularia and a mixture patch (Ziziphus spina cristi Ziziphus nummularia). More soil stability in the mixed patch of trees and shrubs (Ziziphus spina cristi Ziziphus nummularia) could be promising for biological control in south winter rangelands of the country.