Livestock-cropland re-coupling and intensive farming: strategies for enhancing greenhouse gas mitigation and eco-efficiency in wheat-maize production in North China Plain

Using manure compost can be an effective strategy to sustain crop production, mitigate greenhouse gas (GHG) emissions, and promote soil organic carbon (SOC) sequestration. However, in the North China Plain (NCP)-a key food hub in China-the disconnect between livestock farms and croplands limits manure recycling, obscuring its potential environmental benefits and economic costs. This study employs a life cycle assessment method to quantify GHG and ammonia emissions, SOC sequestration, economic performance, and the eco-efficiency of wheat-maize production in the NCP across six livestock-cropland coupling scenarios: farmers' practice (FP), traditional household farming (HF), modern intensive decoupled systems with low (L), medium (M), and high (H) manure returning rates, and an intensive coupled system with optimum manure returning rate (IC). The results show that increasing manure return rates in intensive systems decreases the net global warming potential (NGWP), emphasizing the importance of livestock-cropland re-coupling. Emissions embodied in the field input supply chain was identified as a major NGWP contributor, while SOC accumulation significantly contributed to net GHG mitigation. The IC scenario is both the most economically viable ($322.8 (t grain)-1) and eco-efficient (1.03 kg CO2-eq USD-1) system. With the same compost application rates, intensive farming reduced the NGWP by 26.1% compared to household farming, despite trade-offs between GHG and NH3 emissions. The FP scenario had the highest climate impact (722.8 kg CO2-eq (t grain)-1) and the lowest eco-efficiency (4.91 kg CO2-eq USD-1). These insights advance our understanding of sustainable management practices for pursuing synergistic progress in economic gains, environmental conservation, and sustainable agricultural production.