灰水足迹视角下我国省域农业生态效率及其影响因素

【目的】从灰水足迹视角评价我国省域农业生态效率，揭示农业生态效率的空间分布特征，分析影响农业生态效率的主要因素，据此提出提升我国省域农业生态效率的政策建议。【方法】利用我国2000—2019年的省级面板数据，考虑非期望产出的超效率SBM模型对我国省域农业生态效率进行综合评价，采用空间杜宾模型对农业生态效率的空间差异与影响因素进行分析。【结果】（1）总体而言，农业灰水足迹呈下降趋势，但个别省（市、区）呈上升趋势。从灰水足迹由低到高的排名可以看出，处于前列（即灰水足迹较小）的省（市、区）经济发展水平较高或农业产值占比较低；处于后列（即灰水足迹较高）的省（市、区）经济发展水平较低或农业产值占比较高。（2）观测期内，农业生态效率总体平稳，个别年份波动较大，各省（市、区）的均值差距明显且分布极不平衡。（3）经济发展水平、种植业结构、技术进步、财政支农、农业受灾率等因素对中国农业生态效率的影响程度各异。随着经济发展水平与人们生活质量的双双提升，无论是农业经营者还是消费者对农业生态环境保护和农产品质量的重视程度日益提升，在一定程度上改善了区域农业生态效率水平，但是地区经济社会发展产生的污染也可能对农业生态效率产生负面影响；财政支农的大部分资金使用在对农药、化肥和农机等生产资料的补贴上，虽然改善了农业生产条件，提高了农业经济生产力和效率，但对农业生态效率的提升效果不显著；技术的发展在农业生产过程中很重要，使用得当会提高农业生态效率；农业受灾率的估计结果未通过显著性检验，可能是因为农业受灾面积的扩大导致农业生态效率的下降，但每年的受灾情况并不具有规律性；种植业结构的系数为负，其对农业生产效率产生了负面影响，可能是因为粮食作物种植面积占作物总播种面积比例较高，且消耗的氮肥数量较多。【结论】由于我国各个省（市、区）的农业灰水足迹演变趋势和差异明显，农业生态效率整体水平不高，且各个因素对农业生态效率的影响程度不一。因此，需要健全农业灰水足迹治理机制；优化农业产业结构，建立基于灰水足迹的农业水资源保护补偿机制；完善财政支农方式和政策，引导经营主体积极提升农业生态效率。

Provincial Agricultural Ecological Efficiency and Its Influencing Factors in China from the Perspective of Grey Water Footprint

【Objective】This paper evaluated Chinese provincial agricultural ecological efficiency from the perspective of gray water footprint, revealed the spatial distribution characteristics of agricultural ecological efficiency, analyzed the main factors affecting agricultural ecological efficiency, and put forward policy suggestions to improve Chinese provincial agricultural ecological efficiency. 【Method】Based on the provincial panel data of China from 2000 to 2019, this paper comprehensively evaluated the agricultural ecological efficiency of Chinese provinces with the super efficiency SBM model considering the unexpected output, and used the spatial Dobbin model to analyze the spatial differences and influencing factors of agricultural ecological efficiency. 【Result】(1) In general, the agricultural grey water footprint showed a downward trend, but in some provinces (cities and districts), it showed an upward trend. From the ranking of grey water footprint from low to high, it could be seen that the provinces (cities and districts) in the forefront (i.e. with less grey water footprint) had a high level of economic development or a relatively low proportion of agricultural output value; the provinces (cities and districts) in the rear row (i.e. with more grey water footprint) had low economic development level or high agricultural output value. (2) During the observation period, the agricultural ecological efficiency fluctuated greatly in some years in the stable trend, and the average difference among provinces (cities and districts) was obvious and the distribution was extremely unbalanced. (3) Economic development level, fiscal expenditure for supporting agriculture, technological progress, agricultural disaster rate, planting structure and other factors had different impacts on Chinese agricultural ecological efficiency. With the improvement of both economic development level and people's living quality, both agricultural operators and consumers paid more attention to the protection of agricultural ecological environment and the quality of agricultural products, which have improved the level of regional agricultural ecological efficiency to a certain extent. But the pollution caused by regional economic and social development might also have a negative impact on agricultural ecological efficiency. Most of the financial support for agriculture was used to subsidize production links, such as pesticides, chemical fertilizers, and agricultural machinery. Although the agricultural production conditions have been improved and the agricultural economic productivity and efficiency have been improved, the improvement of agricultural ecological efficiency was not significant. The development of technology was very important in the agricultural production process, and the proper use of it would improve the agricultural ecological efficiency. The estimated results of agricultural disaster rate failed to pass the significance test, which might be because the expansion of agricultural disaster area would lead to the decline of agricultural ecological efficiency, but the annual disaster situation was not regular. The coefficient of planting structure was negative, which had a negative impact on agricultural production efficiency. This might be due to the high proportion of grain crop planting area in the total planting area of crops, and the high consumption of nitrogen fertilizer. 【Conclusion】As the evolution trend and difference of agricultural gray water footprint in various provinces (cities and districts) in China were obvious, the overall level of agricultural ecological efficiency was not high, and various factors have different impacts on agricultural ecological efficiency, it was necessary to improve the governance mechanism of agricultural gray water footprint; optimize the agricultural industrial structure and establish a compensation mechanism for agricultural water resources protection based on gray water footprint; improve the ways and policies of financial support for agriculture, and guide business entities to actively improve agricultural ecological efficiency.