Influence of land use on changes of sediment budget components: western Iran case study

Authors: FATEMEH SEDIGHI, ABDULVAHED KHALEDI DARVISHAN, VALENTIN GOLOSOV, MOHAMAD REZA ZARE, VELIBOR SPALEVIC

Abstract: Understanding the processes of displacement and redistribution of soil particles caused by different erosion types is considered an efficient sediment management tool in various scales from the field plot to the watershed. The rainfed agriculture practices on high gradient slopes are one of the main sources of accelerated soil erosion due to the disturbance of soil structure by tillage processes. Therefore, the present study aimed to investigate the synergistic effect of rainfed agriculture practices and slope gradient on soil erosion using the activity concentrations of 137Cs fallout in Khamsan experimental watershed, western Iran. The diffusion and migration model was used for undisturbed soils and mass balance equation type II was used for agricultural lands. The distribution map of soil erosion and deposition of the watershed was prepared using 137Cs method and the interactions between rainfed agriculture and slope gradient (as the most effective geomorphological factor) on erosion rate and sediment redistribution were evaluated. The results indicated that the highest rates of soil erosion in rainfed agriculture (11.46 t ha^-1 year^-1) and rangeland (1.27 t ha^-1 year^-1) were recorded in the slope gradient classes of 20%-30% and >60%, respectively. In addition, the maximum sedimentation in rainfed agriculture (5.78 t ha^-1 year^-1) and rangeland (0.89 t ha^-1 year^-1) occurred in the slope classes of 30%-60% and in >60%, respectively.

Keywords: Accelerated soil erosion, fingerprinting, cultivated fields, sediment redistribution, sediment source

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