环境约束下的洞庭湖平原耕地利用效率动态演变特征分析

目的 洞庭湖平原是长江中下游重要的粮食生产基地，同时也是重要生态功能区，探究其耕地利用效率动态演变特征，为有效治理洞庭湖平原耕地面源污染问题，提高耕地利用效率，缩小地区间效率不平衡提供参考依据。方法 文章基于环境约束视角下构建耕地利用效率评价指标体系，采用非期望产出的超效率SBM模型对洞庭湖平原耕地利用效率进行测度，并基于Malmquist-Luenberger指数模型及核密度估计法探究其动态演化特征。结果 （1）耕地利用过程中产生的面源污染及碳排放对耕地利用效率产生显著的负影响效应；（2）洞庭湖平原耕地利用效率在研究时限内呈平缓的“升—降—升”演变趋势，整体耕地利用效率均值为0.861，未达到最有效的生产前沿，效率损失的主要原因为生产要素投入及非期望产出两方面的冗余，其中各项资本要素投入冗余为最主要因素；（3）2007—2017年洞庭湖平原耕地利用全要素生产率年均提高4.7%，技术进步是耕地利用效率总体提高的最主要因素；（4）洞庭湖平原耕地利用效率在2007—2017年存在着显著的“双峰”态势，且该极化现象越来越显著，内部差距呈现先变大再缩小的动态演变特征。结论 应对效率低效地区加强农业生态生产意识构建和实施科技助推战略等，以提升洞庭湖平原耕地利用效率。

ANALYSIS ON THE DYNAMIC EVOLUTION CHARACTERISTICS OF CULTIVATED LAND USE EFFICIENCY IN THE DONGTING LAKE PLAIN UNDER ENVIRONMENTAL CONSTRAINTS

Dongting Lake Plain is not only an important grain production base in the middle and lower reaches of the Yangtze River, as well as an important ecological function area.Exploring the dynamic evolution characteristics of cultivated land use efficiency in Dongting Lake Plain can provide reference basis for effectively controlling cultivated land non-point source pollution, improving cultivated land use efficiency and reducing inter-regional efficiency imbalance.Based on the perspective of environmental constraints, this paper constructed the evaluation index system of cultivated land use efficiency, used the super efficiency SBM model of unexpected output to measure the cultivated land use efficiency of Dongting Lake Plain, and explored its dynamic evolution characteristics based on Malmquist Luenberger index model and kernel density estimation method.The results were showed as follows. (1) The non-point source pollution and carbon emission produced in the process of cultivated land use had a significant negative impact on cultivated land use efficiency.(2) The cultivated land use efficiency of Dongting Lake Plain showed a gentle "rise drop rise" evolution trend within the research time limit. The average value of the overall cultivated land use efficiency was 0.861, which did not reach the most effective production frontier. The main reason for the loss of efficiency was the redundancy of production factor input and unexpected output, of which the redundancy of capital factor input was the most important factor.(3) From 2007 to 2017, the total factor productivity of cultivated land use in Dongting Lake Plain increased by 4.7% annually. Technological progress was the main factor for the overall improvement of cultivated land use efficiency. (4) The cultivated land use efficiency of Dongting Lake Plain had a significant "double peak" trend from 2007 to 2017, and the polarization phenomenon was becoming more and more significant, and the internal gap showed the dynamic evolution characteristics of first widening and then narrowing.To improve the utilization efficiency of cultivated land in Dongting Lake Plain, we should deal with the inefficient areas, strengthen the construction of agricultural ecological production awareness and implement the strategy of boosting science and technology.