Optimizing agricultural management in China for soil greenhouse gas emissions and yield balance: A regional heterogeneity perspective

Balancing soil greenhouse gas emissions (SGE) with crop production is crucial for sustainable agriculture in China. Optimizing field management practices regionally can effectively promote carbon reduction and food security, given the varying SGE responses across agroecological regions. This study employed meta-analysis and machine learning techniques to assess SGE responses to nine different farming practices in seven distinct agroecological regions. It aimed to identify optimal management strategies for balancing SGE and crop production within each region. Findings underscore substantial spatial heterogeneity in the effects of management practices on SGE, with the combined use of organic and inorganic fertilizers (MOF-MF) demonstrating the most pronounced variability (standard deviation, SD = 1.80), where MOF resulted in SGE 610% of that with MF in the Southern China (SC) region, yet only 54% in Northwestern China (NWC). Conversely, straw incorporation exhibited the most minor variability (SD = 0.27), influencing SGE by 35%-62%. Additionally, the study reveals that soil and climatic conditions significantly modulate SGE responses. In scenarios characterized by humid and warm climates with soil pH ranging from 5.5 to 8.5 or initial SOC <= 10, the environmental impact on SGE was marginal. However, in highly acidic or alkaline soils or with initial SOC >10, SGE responses varied markedly with management practices in arid and cold conditions. The study further proposes agricultural management strategies to achieve the lowest SGE while maximizing crop yield. It recommends specific methods for fertilizer applications, straw management, irrigation, and tillage practices meticulously tailored to the unique conditions of each agroecological region. This research offers essential insights for agricultural stakeholders regarding cultivation strategies and delivers theoretical guidance for enhancing agricultural management and land-use planning throughout China's heterogeneous landscapes.