三峡生态屏障区农业面源污染的排放效率及其影响因素

Study on Emission Efficiency,Shadow Price and Motivation Factors of Agricultural Non-point Source Pollution in Ecological Barrier Zone of Three Gorges Reservoir Area

农业面源污染排放效率反映农业经济发展与环境的协调程度,农业面源污染物的影子价格体现了污染物的边际减排成本。提高农业生产的环境效率,降低农业面源污染的影子价格对保护农村生态环境和增强流域水资源的安全性起到较好的促进作用。利用三峡生态屏障区重庆段2000-2012年间的面板数据,采用参数化方向性距离函数,对农业面源污染的排放效率和影子价格进行了测算,结合面板数据随机效应Tobit模型分析了影响农业面源污染的排放效率和影子价格。结果表明:2000-2012年期间,农业面源污染平均排放效率为0.649 9,TN、TP、COD和NH3-N 4种污染物的平均影子价格分别为0.372 9,0.032 6,0.137 1,0.053 3万元/t;不同区域农业面源污染排放效率和影子价格存在一定的差异,库中平行岭谷区、库区腹地沿江山地丘陵区和库区腹地外围山地区农业面源污染排放效率低,污染物的影子价格高;影响农业面源污染的排放效率和影子价格因素主要包括农业结构中经济作物与粮食作物的比例、农业生产设施条件、农村居民受教育程度。因此,确保粮食作物安全的前提下,进一步优化农业产业结构,减少农药、化肥投入大的农作物种植规模,走"两型农业"之路;进一步加大对农田水利设施、节水灌溉设施和农业生态建设工程的投资,减少和控制农业生产中的污染物排放对生态环境的破坏;农业面源污染源头减排离不开农户的积极参与,提高农户对农业生态环境退化的认知也是解决农业面源污染的重要途径。

Agricultural non-point source pollution emission efficiency reflects the coordination of agricultural economic development and the environment.The shadow price of agricultural non-point source pollution reflects the pollutant marginal abatement cost.The improvement of the environmental efficiency of agricultural production and the reduction of the shadow price of agricultural nonpoint source pollution will protect the rural environment and enhance the security of water resources.By using the 2000-2012 panel data of Chongqing section of Three Gorges reservoir region and the parameters of the directional distance function,the agricultural non-point source pollution emission efficiency and shadow price have been calculated.Based on the random effects panel data Tobit model,the paper analyzes the factors which influence the agricultural nonpoint source pollution emission efficiency and shadow prices.The results show that：during 2000-2012,agricultural non-point source pollution emission efficiency is 0.649 9,the average shadow prices of four kinds of pollutants TN,TP,COD and NH3-N are respectively O.372 9,0.032 6,0.137 1,0.053 3 ten thousands yuan/ton; There are some differences in the agricultural non-point source pollution emission efficiency and shadow price in different areas.The agricultural non-point source pollution emission efficiency in the paralleled ridge valley region of the Three Gorges Reservoir,the hinterland area,the hinterland along the peripheral mountain area is low while the shadow price of the pollutant is high.The factors which influence the agricultural non-point source pollution emission efficiency and shadow price include the proportion of main economic crops and the grain crops,the agricultural production facilities and education level of rural residents.Therefore,it is necessary to optimize the industrial agricultural structure,reduce the scale of crop planting input pesticide and fertilizer in large scale and take the ＂two types of agriculture＂ road.The pollution emission in the agricultural production which results in damages to the ecological environment can be reduced and controlled if the investment is increased in water infrastructure,water-saving irrigation facilities and the construction of eco-agriculture project.At the same time,the agricultural non-point pollution source emission reduction cannot do without farmers＇ participation.To solve the agricultural non-point source pollution,it is also an important way to improve the farmers＇ cognition of agricultural ecological environment degradation.