Study on eco-efficiency of cultivated land utilization based on the improvement of ecosystem services and emergy analysis.

Cultivated land is the result of the cooperation between humans and nature. The utilization of cultivated land hopes to realize a "win-win" situation of food production and ecological protection to promote sustainable development. Previous studies on the eco-efficiency of agro-ecosystem mainly considered material input, agricultural product output and environmental pollution, and did not systematically include the natural input and ecological product output, which had limitations on the study of sustainable development of cultivated land utilization. Therefore, this study initially used emergy analysis and ecosystem service assessment methods to include the natural input and ecosystem service output of cultivated land into the assessment framework of eco-efficiency of cultivated land utilization (ECLU) and used the Super-SBM model to calculate the ECLU in the Yangtze River Delta (YRD) region in China. In addition, we also discussed the influencing factors of ECLU by the OLS model. Here we show that the ECLU was lower in cities with higher agricultural intensive utilization in the YRD. And in cities with better ecological conditions, the ECLU value obtained based on our adjusted ECLU assessment framework was higher than the traditional agricultural eco-efficiency assessment, indicating that the assessment method in this study paid more attention to ecological protection in the application. In addition, we found that crop diversity, paddy/dry land ratio, cultivated land fragmentation and terrain are the factors affecting the ECLU. This study helps provide a scientific basis for decision-makers to improve the ecological function of cultivated land based on ensuring food security and furthermore promote regional sustainable development.