基于面源污染约束的玉米生产效率及其时空差异

采用基于非期望产出的非径向、非角度的数据包络分析模型测算了2006~2016年中国20个省份玉米生产效率并分析了其时空变化特征和影响因素。结果表明,东北区、黄淮海区和蒙新区玉米生产效率较高,但山东和辽宁效率值低于0.90,区内省际间差异较小;长江中下游区、西南区和西北区效率较低,但安徽、重庆、山西和甘肃效率值高于0.90,区内省际间差异较大。玉米生产效率总体上呈降低趋势,两极分化呈先缩小后扩大趋势,低效率地区数量显著增加。近3 a四川和贵州用工投入可缩减比例超过15%,辽宁化肥投入可缩减比例超过10%,吉林和黑龙江资本投入可缩减比例超过5%。总氮和总磷排放强度过高是各省份玉米生产效率降低的普遍原因,湖北、广西、贵州、云南和四川总氮可缩减比例达60%以上,宁夏、陕西和湖北总磷可缩减比例达50%以上。应通过水肥管理减少农田尺度肥料损失,通过布局调整和结构优化控制区域尺度肥料流失。东北区和黄淮海区应重点控制灌溉引起的磷肥排水损失和氮肥淋溶损失,西南区和长江中下游区重点控制暴雨径流引起的氮磷流失,西北区和蒙新区重点通过节水灌溉减少肥料流失。

Maize Production Efficiency and Its Spatio-temporal Difference Based on Non-point Source Pollution Constraints

This article uses a non-radiological and non-angled data envelopment analysis model based on non-desired outputs to measure the efficiency of maize production in 20 provinces in China during 2006-2016 and analyzes its temporal and spatial characteristics and influencing factors. The results showed that the maize production efficiency was higher in the Northeast, Huanghuaihai, and Mengxin district, but the efficiency values in Shandong and Liaoning were lower than 0.90, and the inter-provincial differences were small; the efficiency in the middle and lower reaches of the Yangtze River, southwest and northwest was low. However, the efficiency values in Anhui, Chongqing, Shanxi, and Gansu are higher than 0.90, and there are large differences among the provinces. The overall corn production efficiency showed a downward trend, with the polarities first shrinking and then expanding, and the number of low-efficiency areas increased significantly. In the past three years, labor input in Sichuan and Guizhou can be reduced by more than 15%, Liaoning can reduce the input of chemical fertilizers by more than 10%, and capital investment in Jilin and Heilongjiang can be reduced by more than 5%. Too high emission of total nitrogen and total phosphorus is the common cause of the decrease of maize production efficiency in each province. The proportion of total nitrogen in Hubei, Guangxi, Guizhou, Yunnan, and Sichuan can be reduced by more than 60%, and the total phosphorus in Ningxia, Shaanxi, and Hubei can be reduced by up to above 50%. Farm-scale fertilizer losses should be reduced through water and fertilizer management, and regional-scale fertilizer losses should be controlled through layout adjustment and structural optimization. Northeast China and Huang-Huai-Hai District should focus on controlling the loss of phosphate fertilizer-induced drainage losses and nitrogen fertilizer leaching losses. The Southwest and the middle and lower reaches of the Yangtze River should focus on controlling the loss of nitrogen and phosphorus caused by heavy rainfall runoff. Northwest and Mengxin District should reduce fertilizers through water-saving irrigation.