Assessing methane emissions and multiple benefits of mitigation through coupled crop-livestock system

A potent greenhouse gas, methane, contributes to global warming, primarily from livestock activities such as fermentation and manure management. Recognized as a low-carbon agricultural approach, coupled crop-livestock systems are gaining increasing attention for mitigating methane emissions and environmental impacts. This study focused on Inner Mongolia to estimate its methane reduction potential. We calculated methane emissions using a combination of bottom-up and top-down methods, analyzed livestock distribution, estimated manure production, and assessed the potential of manure to replace chemical fertilizers based on crop nutrient demand. Livestock emissions totaled approximately 769.0 kt. Adopting crop-livestock coupling could reduce emissions by 30.1 kt. Returning manure as fertilizer can cover 57.7% of cropland, saving 57% nitrogen and 20% phosphorus fertilizers, thus reducing costs by $296.3 million. The study has provided a scientific reference for developing methane emission reduction strategies, which can shed light on tackling climate change in the context of agricultural systems.