Improving crop-livestock integration in China using numerical experiments at two scales

Abstract Balancing water quality and food production is a global challenge due to complex nutrient cycle and previous soil accumulation. This study investigated crop-livestock integration from watershed perspective, while agricultural and environmental benefits of fertilizer and manure management were quantified through two numerical experiments. The optimal ratio of replacing chemical fertilizer with manure was found and the spatial configuration of crop-livestock integration at large scale was suggested. Results showed that the period of basic fertilizer was more beneficial to crop yield and the effects of replacing chemical fertilizer with manure on water quality was more prominent. Numerical simulation showed that specific threshold existed to balance water quality protection and agricultural production. Then, by extending the threshold to regional scale, spatially explicit crop-livestock integration was given. This study balances the relationship between agriculture and environment, and provides a theoretical basis for the development of crop-livestock integration.