Multi-objective optimization of soil erosion parameters using response surface method (RSM) in the Emamzadeh watershed

Abstract

Soil erosion is one of the most leading environmental and public health problems in the world which dislodges considerable volumes of soil annually. In order to control soil erosion, several soil factors should be taken into account. Regarding the importance of soil properties on erosion occurrence, it is necessary to focus on soil properties. The aim of this study is to evaluate the effect of physical parameters that consist of sand %, silt %, clay %, SP % and stone % along with hydraulic properties including theta s, theta r, alpha n and Ks (cm/day) on the amount of soil erosion in Emamzadeh watershed. The above-mentioned factors were optimized using response surface methodology. The soil texture in the study area is mostly silty clay loam, and the main soil orders are Entisols and Inceptisols. Moreover, the main land use in the study area is forest–rangeland. The results proved that both physical and hydraulic valuables illustrated a significant effect on all of the independent parameters. The optimized values of different physical parameters were 60.241 for sand, 14 for silt, 41.025 for clay, 58.729% for SP and 3.83% for stone. A theta r of 0.09, theta s of 0.457 alpha of 0.014, n of 1.3 and Ks of 46.01 were found to be optimal values. The results of this study indicated that at optimal studied parameters, the values of the soil erosion before and after application of management scenarios were found to be 11.537 and − 2.253, respectively. Results show that both physical and hydraulic parameters have significant effects at the 1% level on the soil erosion before and after application of management scenarios. The obtained results could assist policy-makers with decisions aimed at minimizing soil erosion in this watershed. In summary, using the simulation–optimization techniques helps to evaluate the effect of management scenarios, then select and apply the best one to minimize the soil erosion outcomes.