Optimization of a Water-saving Planting Structure in an Inland River Basin of an Arid Area Based on Multi-objective Programming: a Study for the Shiyang River Basin in China

Abstract Adjusting the agricultural planting structure is one of the important means to realize agricultural water-saving, especially in inland river basin with droughts and water shortages. In this paper, taking Shiyang River Basin in Northwest arid inland river basin as an example, on the basis of determining the crop water production function, a multi-objective optimization model was constructed, which comprehensively considered the maximization of economic benefits, the green water utilization rate and ecological benefits. The optimized planting structure was obtained by using GAMS (General Algebraic Modeling System) model solver. The results showed that: after optimization, the sown areas of wheat, tubers, vegetables and cotton all increased, of which the sown area of tubers increased the most by 8.81×104ha. The sown areas of corn, oil-bearing crops and fruits all decreased, of which the sown area of corn decreased the most by 8.03×104ha. The optimization results of planting structure were different in different counties and districts. The average contribution rate of planting structure adjustment to total water saving was 75.24%, indicating that planting structure adjustment was the key to water-saving. The water consumption of the same crop was different in different counties. Oil-bearing crops and vegetables were more suitable for planting in the lower reaches, while corn and tubers were more suitable for planting in the middle reaches.