Soil loss and runoff generation in rangeland, rain-fed and abandoned rain-fed agriculture land-uses under simulated rainfall

Soil erosion is a global challenge, seriously threatening soil and water resources andenvironmental qualities. One of the important factors to consider in the process of runoffgeneration and soil erosion is the physical and chemical properties of soils under differentland-uses. The aim of this study is to estimate soil erosion and runoff in rangeland, rain-fedand abandoned rain-fed agriculture in Karafs Watershed (Sarduyeh) in Jiroft County usingrainfall simulation. The experiment was conducted in 2012 and three land-uses withuniform soil and lithology were considered. Simulated rainfalls were 46 and 88 mm.hr-1 ofintensity with 3 iterations, which totaled 36 samples. Soil samples were taken close to thelocations of rainfall simulation from the top 0-20 cm and transferred to the laboratory forfurther analysis. The results showed a significant effect of land-use on runoff and erosion indifferent rainfall intensities, so that the highest runoff was generated in the abandoned rainfedagriculture at the intensity of 88 mm.hr-1, with the least being generated in the rain-fedagriculture at the intensity of 46 mm.hr-1. Likewise, we found that land-use changes had alarge impact on soil erosion, with the highest levels at the abandoned rain-fed agriculturewhich resulted in the increased runoff generation. This factor could be explained by theincreased clay, silt, and lime content at the expense of the removal of sand from these areas.Increasing rainfall intensity to 88 mm.hr-1 led to respectively 14% and 47% higher runoffvolumes and sediment loads compared to the initial intensity.

Soil loss and runoff generation in rangeland, rain-fed and abandoned rain-fed agriculture land-uses under simulated rainfall Keywords:

Erosion , Runoff , Rainfall simulator , Land-use1