基于面源污染约束的油菜生产效率时空变化及成因分析

SPATIAL TEMPORAL CHANGE AND ITS REASON OF RAPESEED PRODUCTION EFFICIENCY BASED ON NON POINT POLLUTION CONSTRAINTS

关键词:  油菜生产效率面源污染时空差异数据包络分析

Key words:  rapeseed  production efficiency  non point pollution  spatial temporal difference  data envelopment analysis

摘要:

［目的］分析面源污染约束条件下我国油菜生产效率的动态变化、省际差异及其影响因素，提出提升途径。［方法］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面源污染约束下的油菜生产效率，根据投入冗余、期望产出不足或非期望产出冗余等，分析效率损失成因。［结果］我国油菜生产效率总体上呈现“N型”年际变化特征，其中黄淮区、江浙、重庆、青海和甘肃的油菜生产效率均值高于09，云贵和内蒙古的油菜生产效率则低于08。全国和长江流域省际差异表现为先扩大后缩小趋势，西北区省际差异最大，黄淮区省际差异最小。总氮和总磷排放量过高是长江流域乃至全国油菜生产效率损失的主要原因。近3年总氮可缩减比例均值大于30%的地区从大到小依次为湖南、内蒙古、贵州、云南和江西，总磷可缩减比例均值大于30%的地区依次为云南、贵州、四川和内蒙古。此外，湖北用工投入冗余、内蒙古化肥投入冗余和单产不足也是其油菜生产效率损失的重要原因。［结论］长江流域需重点削减氮磷径流损失，黄淮区应重点控制氮磷淋溶损失，西北区应重点治理氮磷侵蚀流失。

Abstract:

This paper is intended to analyze the dynamic changes, inter provincial differences and its influencing factors of rapeseed production efficiency under the constraints of non point source pollution, and proposes improvement approaches. A non radiological and non angled data envelopment analysis model based on non desired outputs was used to measure the rapeseed production efficiency in 15 provinces in China from 2008 to 2016. The reasons of efficiency loss were analyzed based on input redundancy, insufficient expected output, or undesired output redundancy. The results showed that the inter annual variation of rapeseed production efficiency in China could be characterized by "N shape". The average rapeseed production efficiency in Huanghuai district, Jiangsu, Zhejiang, Chongqing, Qinghai and Gansu province was higher than 0.9, while the rapeseed production efficiency in Yungui and Inner Mongolia was lower than 0.8. The inter provincial differences in the whole country and the Yangtze River Basin showed a trend of first expanding and then shrinking. The north western region had the largest inter provincial difference and the Huanghuai region had the smallest inter provincial difference. Excessively high total nitrogen and total phosphorus emissions were the main reason for the loss of rapeseed production efficiency in the Yangtze River Basin and even in the whole country. In the past three years, provinces with an average reduction ratio of total nitrogen greater than 30% were Hunan, Inner Mongolia, Guizhou, Yunnan, and Jiangxi in descending order, and provinces with an average reduction ratio of total phosphorus greater than 30% were Yunnan, Guizhou, Sichuan, and Inner Mongolia. In addition, In addition, redundant labor input in Hubei, redundant fertilizer input and insufficient yield in Inner Mongolia were also important reasons for the loss of rapeseed production efficiency. The Yangtze River Basin should focus on reducing nitrogen and phosphorus runoff losses. The Huanghuai district should focus on controlling nitrogen and phosphorus leaching losses, and the Northwest district should focus on controlling nitrogen and phosphorus erosion losses.