RESUMEN
Farmland ecosystems can provide both economic products and ecosystem services that are important in maintaining food security and ecological safety. However, the ecological functions of farmland ecosystems have not been adequately evaluated in China, especially from the perspective of ecological efficiency for three staple food crops (wheat, maize and rice). Moreover, the contribution of ecosystem services value (ESV) to agricultural eco-efficiency (AEE), and the factors that influence AEE for the three staple food crops in different regions are still unclear. In this study, data envelopment analysis (DEA) was applied to calculate the AEE using group-frontier and meta-frontier methods based on regional heterogeneity. We measured AEE for wheat, maize and rice production with and without ESV and compared the gap between ecological inefficiency resulting from management inefficiency and technology gap inefficiency. The research results showed that, first, the involvement of ESV could effectively promote AEE. In particular, water conservation, soil conservation and the nutrient cycle contributed to the promotion of eco-efficiency. The mean ΔAEE (the difference in AEE with or without ESV) of wheat, maize and rice increased by 15 %, 10 % and 13 % with group-frontier and by 20 %, 10 % and 11 % with meta-frontier, respectively. Second, the improvement of AEE was higher in ecologically sensitive areas than that in other areas, especially for wheat and rice. Third, although the involvement of ESV reduced ecological inefficiency, specifically for management inefficiency, its contribution differed significantly across regions. We provide suggestions on improving AEE and reducing inter-regional differences in China. In brief, these findings suggest that, except for grain yields, ecosystem services need to be recognized in the production of three staple food crops, especially in ecologically sensitive areas. This is helpful for crop planning and planting division in terms of sustainable development.