Responses of different agricultural structures to nitrogen loss and agricultural green development in Northwest China

Nitrogen (N) is a critical nutrient element for enhancing grain yield. Quantifying N flow and exploring N indicators are essential for minimizing N loss to the environment and assessing green agricultural development. However, detailed quantitative research on the contributions of different agricultural structures to N loss is lacking. Previous studies have not adequately explained the specific contributions of different agricultural structures, such as crop farming and livestock rearing, to environmental N loss, especially in terms of N inputs and loss pathways in crop and livestock systems. In this study, focusing on typical cropping and livestock counties in Northwest China, the Nutrient flows in Food chains, Environment, and Resource (NUFER) model was applied to quantify the relative contributions of different agricultural structures to N loss. In 2017, N inputs in cropping and livestock systems were primarily from N fertilizers (>50%) and exogenous feed (>80%). Ammonia volatilization (>60%) and waste (manure and urine) excretion (>55%) were the main pathways responsible for N loss to the environment. Scenario analysis revealed that after implementing appropriate N regulation, soil N accumulation was decreased by 78.9%, N utilization efficiency was increased by 18.3%, and the optimization rate of green agricultural development indicators reached 43%. The results provide a scientific basis for supporting county-level ecological conservation and sustainable agricultural development. The findings emphasize the importance of using quantitative methods to assess the impacts of different agricultural structures on N loss, and provide guidance for implementing more effective N management strategies.