Resumen
In-depth analysis of spatial and temporal variations in the ecological efficiency of agricultural land has important theoretical and practical significance in achieving the efficient utilization of agricultural land, the coordinated development of natural resources and the environment, and the formulation of sustainable agricultural development policies. By including carbon emissions and pollution as undesired output indicators of agricultural land use, and introducing ecological service values as output indicators, an SBM-Undesirable model which can not only avoid the deviation caused by the difference of radial and angular selection, but also reflect the essence of efficiency evaluation, was used to estimate the ecological efficiency of agricultural land in 30 provinces, municipalities and autonomous regions of China from 2004 to 2017. Spatial and temporal differences were then analyzed. The results show that (1) The ecological efficiency of agricultural land in China decreased overall from 2004 to 2017. (2) The eco-efficiency of agricultural land was highest in the eastern provinces, lowest in the central provinces, and moderate in the western provinces. (3) Among the input indicators, the input redundancy rates of agricultural land, chemical fertilizer input and agricultural film input were too high. (4) China?s agricultural land use has not evolved towards harmonious development of the environment and economy. Due to the excessive use of chemical fertilizers, agricultural films and other factors that cause pollution, there has been a one-sided increase in the economic output of agricultural land, and improvements in ecological value have been inhibited. Based on the research results, feasible suggestions are put forward to improve the ecological efficiency of agricultural land in China.