The Impact of Haloxylon Plantation on Some Soil Erodibility Indices on the Sandy Lands of Taybad

Erodibility as a dynamic property of soil depends on the soil`s aggregate stability and initial large particles percentage which are resistant to erosion. One of the effective factors on soil erosion is soil aggregate stability and its efficient components. Due to the presence of stabilized sand seas which is affected via different plantation development of Haloxylon in the desert area of Taybad, this paper examine the effect of soil organic amounts on some erodibility indices of surface soil. For this purpose, five sites were selected based on Haloxylon plantation ages (41, 28, 19 and 11 years old and one control site (no Haloxylon plantation). Considering planting age of Haloxylon, the results represent a 24% reduction in sand content and 14 and 8% increasing in silt and clay contents respectively were observed. Maximum mean weigh diameter (2.48 mm) was belonging to the 41- years- old Haloxylon plantation. Clay ratio indicator has changed from 5.23% in the control site to 3.06% at the 41-years-old site. Modified clay ratio has changed from 5.21% in the control site to 3% at 41-years-old Haloxylon plantation. Organic matter increased from 0.05% in the control site to 0.4% at the 41-years-old site. Results show that the mean weigh diameter index has a progressively increase tend but clay ratio index and modified clay ratio index has a decreasing trend. The overall results of this research indicated that Haloxylon plantation enhancing soil aggregate stability and decreased soil erodibility.