Erosion Control by Amending Soil with Gypsum in the Dawlatzai Village of Gardez District, Afghanistan

Abstract

Minimizing soil and water loss in agricultural land, particularly in arid and semi-arid climatic conditions, is indispensable for environmental protection and agricultural production. The purpose of this research is to evaluate the effectiveness of gypsum application in reducing sediment concentration in runoff and total soil loss. A field experiment was conducted in the village of Dawlatzai in Gardez District, Paktya, Afghanistan. Using a portable rainfall simulator, four erosion plots; gypsum-treated, clover, maize, and control were designed and applied in two replications. Surface runoff experiment using sandy loam and loamy soil textures was conducted in the Laboratory of Land and Water Use Engineering, Tokyo University of Agriculture. Gypsum mineral was applied at a rate of 5 t ha^-1 for both experiments. The results of field experiments showed that the gypsum-treated, clover and maize fields reduced total soil loss by 67.28%, 92.04% and 54.45% compared to the control, respectively. Likewise, surface runoff was reduced by 19.62% in the gypsum-treated field compared to the control field. Similarly, the results of laboratory experiment showed that with application of gypsum, surface runoff was reduced by 38.83% and 37.07% from sandy loam and loamy soil textures with total soil loss reduced by 60.25% and 81.86% compared to control, respectively. Percolation was increased by 2.31 and 2.29 times in sandy loam and loamy soil textures, respectively. Moreover, the application of gypsum significantly reduced sodium adsorption ratio (SAR) and boosted the calcium content and flocculation phenomena. Based on these results, it can be suggested and recommended that farmers in Paktya should apply gypsum mineral to their farmlands to enhance water infiltration and minimize surface runoff and soil loss.