江西省农用地生态效率时空差异及影响因素分析——基于面源污染、碳排放双重视角

科学剖析农用地生态效率时空差异及影响机制,对实现农用地利用与资源环境协调发展以及制定农业可持续发展政策具有重要的理论与实践意义。将农用地面源污染、碳排放作为非期望产出纳入农用地生态效率评价指标体系,借助SBM-Undesirable模型对1990～2017年江西省农用地生态效率进行测度并对其时空差异特征进行分析,在此基础上运用Tobit模型探讨相关因素的影响机制。结果表明:(1)1990～2017年间江西省农用地生态效率呈现"先下降后上升"的变化趋势,均值为0.749,总体呈现上升的趋势;(2)各设区市农用地生态效率空间格局演变轨迹呈现先下降后上升的扁平"U"型特征,高效率地区由"连片"分布向"点状"分布再向"连片"分布变化,空间格局趋于非均衡化发展;(3)农村居民人均可支配收入、复种指数、农村劳动力文化程度和劳均播种面积对农用地生态效率产生显著正影响,城乡收入差距则产生显著负影响。最后,从优化资源要素配置、加强农业科技创新应用、健全农村土地流转制度、摒弃过度依赖资源要素投入与环境污染的粗放型发展模式、走"精耕细作"和可持续发展的农业生态文明发展道路等方面提出了提高农用地生态效率的政策建议。

Spatial-temporal Differences and Influencing Factors of Agricultural Land Eco-efficiency in Jiangxi Province：Based on the Dual Perspective of Non-point Source Pollution and Carbon Emission

Land resources are the material basis for human survival and development, but the extensive land management mode brings a series of serious challenges: land resources are limited, non-point source pollution aggravated, the quality of agricultural land deteriorated, agricultural carbon emissions increased sharply, agricultural land conversion, etc. This development model at the expense of resources and environment has seriously restricted the sustainable development of agricultural economy. It is of great theoretical and practical significance to scientifically analyze the spatial-temporal differences and impact mechanism of agricultural land ecological efficiency for realizing the coordinated development of agricultural land use, resources and environment, and formulating sustainable agricultural development policies. In this paper, Jiangxi Province was taken as a typical case study area. First, inventory analysis and carbon emission coefficient method were used to calculate the pollution and carbon emissions of agricultural surface sources，and then it was incorporated into the SBM-Undesirable model of undesirable output. Secondly, the ecological efficiency of agricultural land was quantitatively measured and the spatial-temporal pattern of the study area was revealed in Jiangxi Province and its districts and cities from 1990 to 2017. Finally, it used the Tobit regression model to discuss the influence mechanism of relevant factors. The results showed that: (1) From 1990 to 2016, the ecological efficiency of agricultural land in Jiangxi Province showed a “first decreased and then increased” trend, with an average value of 0.749, showing an overall upward trend;(2) The spatial pattern of eco-efficiency of agricultural land in Jiangxi Province was characterized by a flat “V” feature that decreased first and then increased. The high efficiency regions changed from “serial” distribution to “spot” distribution and then to “serial” distribution, and the spatial pattern tended to be unbalanced; (3) The per capita disposable income of rural residents, multiple cropping index, cultural proportion of rural labor force above senior high school and per capita sowing area had significant positive effects on the ecological efficiency of agricultural land in Jiangxi Province, while the income gap between urban and rural areas had significant negative effects. Finally, the paper putting forward some suggestions to improve the ecological efficiency of agricultural land from the aspects of optimizing the allocation of resources, strengthening the innovation and application of agricultural science and technology, perfecting the rural land circulation system, abandoning the extensive development model of excessive dependence on resources and factors input and environmental pollution, taking the “intensive cultivation” and sustainable development of agricultural ecological civilization. Meanwhile, there are still some somewhat limitations in this study: (1) In the aspect of unexpected output, the loss of agricultural land ecological efficiency caused by unexpected output, such as rural domestic sewage or rural industrial wastewater discharge pollution, has not been considered; （2) The differences of initial land quality and soil fertility among different regions have not been included in the evaluation system of agricultural land ecological efficiency; （3) In the analysis of impact mechanism, the micro-factors such as farmers’ willingness to adopt agricultural science and technology, pollution prevention and control are not included in the analysis. The spatial and temporal differences of agricultural land ecological efficiency and its influencing mechanism are the result of many factors, which provide an important direction for further research in the future.