Systematic research and quantitative approach for assessing agricultural green development

Research on agricultural green development (AGD) is a scientific direction of integrating multi-disciplinary knowledge. It takes the food system as the research boundary, and focuses on analyzing the relationship between different sectors in the food system to achieve the targets of food security, human health, resource conservation and environmental protection. It also devotes attention to the coordination of "green" and "development" in agriculture production system. Previous methods often neglect systematically thinking and quantitatively analyzing of the AGD, and cannot coordinate multiple objectives of AGD. In this study, we firstly defined the research boundary of AGD, which considered "soil-crop production-animal production-food processing-household consumption-environmental impacts" systems; secondly, we developed the quantitative research approaches of "top-down" and "bottom-up", combining the whole food chain and multi-scale characters in AGD studies; thirdly, we developed the new modelling system for AGD (NUFER-AGD), including a core model (the food system nutrient flow model, NUFER), three quantitative analysis modules (water, atmosphere and land use modules) and one index module (linked to Driving force-Pressure-States-Impacts-Response, DPSIR; Sustainable Development Goals, SDGs; and Planet Boundaries, PBs); and last, we reviewed several case studies of quantitative research on AGD. Here, case studies were conducted by following 3 steps: (1) coordinating the overall goals AGDs at national level by nexus analysis approach and multiple indicators evaluation; (2) designing AGDs solutions quantitively by using green environment and resource limits as thresholds at the watershed scale; (3) analyzing the technical pathways of AGD systemically in the whole industrial chain. This research can not only provide systematic thinking and quantitative methods for the research of AGD, but also provide scientific support for the national strategy of AGD in China.