Optimizing Land Use Pattern to reduce soil erosion, Case Study: Qushchi Watershed

Soil erosion hazard in catchments are the major problems that can affect ecological balance of such areas. This study aimed to determine the optimal use of land to reduce erosion and increase the resident's income of Qushchi watershed in West Azerbaijan province. Income and expenses for the current land uses were calculated with field studies. Damages resulting from the soil erosion were estimated by soil depth equal to the specified land uses. For three different options including the current status of land uses without and with land management, and the standard status of land uses, multi-objective linear programming model was established by LINGO software. Then the optimization problem of the land use was solved by simplex method. Finally, the best option of land use was determined by comparing erosion rate and its cost in each scenario. Then the circumstances and the recommended conditions were compared. The results indicated that the current surface area of current land uses is not suitable to reduce erosion and increase income of residents and should change in the optimum conditions. At the optimum level, horticulture area of 408 to 507 (ha), irrigated land area of 169 to 136 (ha) and Dry farming of 636 to 570 (ha) should change while conversion of rangeland area not indispensable. In addition, the results showed that in case of the optimization of land use only, soil erosion and the profitability of the whole area will 0.75 percent decrease and 3.68 percent increase respectively. In case of land management practices, 42.27 percent will decrease and 21.39 percent increase and with the standard conditions 60.95 percent will decrease and 24.20 percent increase. The results of the sensitivity analysis showed that the change in the horticulture and range land have the greatest impact on increasing profitability and reducing soil erosion of Qushchi watershed.