2017 Volume 8 Issue 1 Pages 139-149
Soil erosion is a serious problem in Afghanistan, which has been accelerated by improper land management day by day and a growing problem especially in agricultural land. The land in the country is facing continuous soil loss and sediment accumulation due to the irregular topography, deforestation and desertification. It does not only reduce agricultural and livestock production, but also decrease the water availability for irrigation purpose. This study focused on the estimation of the rate of soil loss and soil erosion risk using Universal Soil Loss Equation (USLE) and ArcGIS for the Gardez basin Paktya Province, Afghanistan. All factors used in USLE (R, K, L, S and C) were calculated for the study area using local data. The best equation for estimating the R value from the annual rainfall was discussed on the basis of the observed annual rainfall with the installed rain gauge. Also, all factors were presented by raster layers in ArcGIS platform then multiplied together to predict soil loss (A). The results indicated that the annual soil loss within Gardez Basin ranges from 0 to greater than 100 t ha-1 y-1. The value was divided into five (5) risk classes. The result showed that slight class of soil loss having a range of soil loss between 0 to 5 t ha-1 y-1, moderate class having rates between 5 to 10 t ha-1 y-1, high class having rates between 10 to 50 t ha-1 y-1, severe class rates between 50 to 100 t ha-1 y-1 and very severe class rates greater than 100 t ha-1 y-1, covering 64.31%, 13.95%, 19.76%, 1.76% and 0.22% of the Gardez Basin area, respectively. Most of the agricultural lands are slight to high soil loss categories. However, high soil erosion is found in the barren land, rangeland and rainfed agricultural land. The soil erosion risk is extremely higher on steep slope and foothills. Based on the mean soil erosion value of different land use classes, target land use for conserving strategies was discussed for planning soil conservation practices.