中国粮食生态效率：水平测度、时空格局演变与影响因素

为揭示中国粮食生产生态效率水平及变化特征，基于超效率 SBM 模型对 30 个省份 2000—2021 年粮食生态效率进行估算，通过非参数核密度分析揭示其演进特征，进而通过固定效应模型分析其影响因素。结果表明：从粮食生态效率水平来看，2000—2021年中国粮食生态效率由0.662上升至0.787，年平均增长0.827%。主产区和产销平衡区粮食生态效率的变动趋势与全国层面相近，主销区则远低于全国平均水平；从时空格局演变来看，中国粮食生态效率长期存在高-高集聚、低-低集聚的两极分化现象，且随着时间推移逐渐向较高水平一侧集聚，呈现出北方高于南方、粮食主产区高于粮食非主产区的特征；在各影响因素中，人均GDP、粮食经营规模的影响显著为正，化肥施用强度、农业机械强度和自然灾害的影响显著为负。研究表明，中国粮食生态效率总体水平仍较低且区域差距较大，多数省份未达到效率前沿面，存在较大的提升空间。

Grain eco-efficiency in China：horizontal measurement, spatio-temporal pattern evolution and influencing factors

To reveal the level and variation characteristics of China''s grain production eco-efficiency, this paper estimates the grain ecoefficiency of 30 provinces from 2000 to 2021 based on the super-efficiency SBM model, reveals its evolution characteristics through nonparametric kernel density analysis, and analyzes its influencing factors through fixed effect model. The results show that：from the perspective of grain eco-efficiency level, China''s grain eco-efficiency increased from 0.662 to 0.787 from 2000 to 2021, with an average annual increase of 0.827%. The change trend of grain eco-efficiency in the main production area and the production and marketing balance area is similar to the national level, while the main sales area is far lower than the national average; from the perspective of the evolution of spatial and temporal patterns, China''s grain eco-efficiency has long been polarized between high-high agglomeration and low-low agglomeration, and has gradually gathered to a higher level over time, showing the characteristics that the north is higher than the south, and the major producing areas are higher than the non-main producing areas. Among the influencing factors, the influence of per capita GDP and grain operation scale is significantly positive, and the influence of chemical fertilizer application intensity, agricultural machinery intensity and natural disasters is significantly negative. The research shows that the overall level of China''s grain eco-efficiency is still low and the regional gap is large. Most provinces have not reached the efficiency frontier, and there is a large room for improvement.