基于非期望产出的柑橘生产效率及其时空差异

［目的］研究基于非期望产出的中国柑橘生产效率及其时空差异，旨在为提高环境约束条件下的柑橘生产效率提供理论参考。［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了面源污染约束下2008—2017年我国柑橘生产效率并分析了其时空变化特征和损失原因。［结果］华中和华东区柑橘生产效率较高，华南和西南区较低。各省效率损失原因如下：用工投入冗余主要发生在广东和湖南两省，资本投入冗余主要发生在湖北、江西和福建，多数省份都存在化肥投入冗余和一定增产空间。此外，总氮和总磷流失量过高是各省份柑橘生产效率降低的普遍原因。［结论］我国柑橘生产效率有一定损失，且存在省际间和年际间差异，总氮和总磷流失量过高、化肥投入冗余、单产不足等是生产效率损失的主要原因。因此，应通过品种改良、柑橘生产管理技术改进来提高单产，通过水肥精细化管理提高肥料利用率，通过增加植被覆盖度、改进耕作方式和减少化肥用量来降低总氮和总磷流失量。

TANGERINES PRODUCTION EFFICIENCY AND ITS SPATIO TEMPORAL DIFFERENCE BASED ON UNDESIRED OUTPUT

The objective of this paper is to study tangerines production efficiency and its spatio temporal difference based on undesired output in China, in order to provide theoretical reference for improving the production efficiency of tangerines under environmental constraints. A non radiological and non angled data envelopment analysis model based on undesired outputs was used to measure the production efficiency of tangerines under non point source pollution constraints in China from 2008 to 2017. In addition, the temporal and spatial characteristics of tangerine production efficiency and their loss reason were discussed. The results showed that the tangerines production efficiency was higher in Central China and East China than that in South China and Southwest China. The reasons for efficiency loss in different regions were showed as follows. Labor input was too much in Guangdong and Hunan, capital investment was too much in Hubei, Jiangxi, and Fujian, and the input of fertilizers was too much in most provinces. In addition, the high emission of total nitrogen and total phosphorus was the common cause of the decrease of tangerines production efficiency in each province. It concludes that there is a certain loss of tangerines production efficiency in China. Tangerines production efficiency was different from province to province and year to year in China. Factors such as the high emission of total nitrogen and total phosphorus, too much fertilizer input and too little yield are the main reasons for the loss of tangerines production efficiency. The tangerine yield should be improved through variety improvement and improvement in citrus production management techniques. Fertilizer utilization should be improved through rational management of water and fertilizer, and total nitrogen and total phosphorus losses should be reduced by increasing vegetation cover, improving farming practices and reducing fertilizer use.