A methodological approach to assess the combined reduction of chemical pesticides and chemical fertilizers for low-carbon agriculture

The extensive use of synthetic chemicals for pest control is recognized as a major threat to ecosystem integrity and the realization of low-carbon agriculture. There have been many studies of agrochemical reduction technologies, but little work to date has been done to achieve a combined reduction of chemical pesticides and chemical fertilizers. This fact has led us to the conception of assessment methodologies and the establishment of a relevant ecological model. A significant challenge to the development of assessment methodologies is agro-ecosystem complexity. In this study, we explain the agro-ecosystem as one composed of various social, economic and natural factors that can be defined using a comprehensive positive/negative effect evaluation index system, which is based on fuzzy theory and can be used to assess combinations of technologies for reduced use of chemical pesticides and fertilizers in cauliflower fields. On this basis, a technology using 14% calcium superphosphate 750 kg hm−2, 46% urea 825 kg hm−2, 12% granular boron fertilizer 4.5 kg hm−2, active pesticides 3.09 kg hm−2 and hanging sex pheromone lure on the watermelon-cauliflower rotation mode resulted in the largest index evaluation value (0.3795) and was considered the best combined reduction technology in Chongming Eco-island, Shanghai of China. The results of our study should be of interest to policy makers and environmental managers who seek to realize low-carbon agriculture and to farmers who seek to optimize application technology in practice.