Role of deforestation and land use change on soil erodibility of loess in eastern Golestan province

In order to study the effect of deforestation and tillage practices on soil erodibility، a loess hillslope was selected in eastern Golestan province، Agh-Su watershed. Five pedons in forest land use and also five pedons in adjacent cultivated land were dug on each slope position and studied morphologically. Some undisturbed clods were also sampled from different soil horizons with Kubiena boxes for microscopic studies. Total fifty samples were taken from surface layers of forest and also cultivated land use for physico-chemical analysis. Results showed that the amount of silt particles increased from 57. 6% in surface layer of forest to 68. 4% in cultivated land use. The amount of silt and very fine sand particles also increased in cultivated area relative to forest. Organic matter decreased from 3. 5% in surface layer of forest to 1. 0% in the same layer in cultivated land. Deforestation and tillage practices reduced the MWD value from 1. 49 mm in forest to 0. 88 mm in cultivated land. Micromorphological studies revealed that favorable granular and crumb structures were converted to compact and massive by deforestation. Due to these changes، soil erodibility factor increased، especially in the shoulder، backslope and footslope positions.