Irrigation water efficiency based on stochastic production frontier and influencing factors:An empirical study of wheat in Guanzhong Region, Shaanxi

Water resources are scarce in China, with a per capita water resource of 2 300-2 500 m³ which is only 1/4 of the world's average. Because of water shortages, there has been continuous conflict between various water consuming sectors. This has made it necessary to conduct studies on the efficiency of agricultural irrigation water for sustainable development. Although irrigation water efficiency has been studied in China, such research driven by micro-data is largely lacking for Northwest China. In this paper, a stochastic frontier analysis (SFA) model based on Cobb-Douglas production function was used to measure technical efficiency of wheat farmers and irrigation efficiency in Guanzhong Region, Shaanxi. Then the Tobit model was used to determine the influencing factors of irrigation efficiency. A total of 12 variables were selected, which reflected the personal, family, irrigation and cultivated land characteristics of farmers in the region. The results showed that technical efficiency of wheat farmers in Guanzhong Region was relatively high, with a range of 0.7-1.0 and a mean of 0.87. Irrigation efficiency was 0-0.5 and the mean was 0.31, which was far below technological efficiency. Analysis of the influencing factors of irrigation efficiency showed that farmers' education level, family economic status, irrigation channel condition, water shortage degree and irrigation water-saving degree had significant positive impact on irrigation efficiency. Then off-farm employment and non-farm income had a negative impact on irrigation efficiency. Age of farmers, irrigation water price, planting scale and subdivision of cultivated land had no obvious correlation with irrigation efficiency. Thus the study not only revealed the current conditions of wheat irrigation efficiency in Guanzhong Region, but also put forward critical suggestions on agricultural water resources management through the study of the influencing factors. The study also provided a reference base for improving irrigation water efficiency in Guanzhong Region in Shaanxi Province.