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

Abstract

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