May 1, 2024 | Journal of Cleaner Production | Source |
Introduction: Region-specific strategies are critical for China to balance crop production and environmental sustainability. This study, led by researchers from Nanjing University and Groningen University, integrates meta-analysis and machine learning to assess the effects of various farming practices on soil greenhouse gas emissions (SGE) across seven agroecological regions. By modeling regional variations, it aims to identify optimal management strategies that reduce emissions, enhance yields, and support sustainable agriculture.
Key findings: The study evaluated the impact of chemical and organic fertilizers, tillage, straw incorporation, and irrigation on SGE, considering soil properties (pH, soil organic carbon/SOC) and climatic factors (humidity, temperature). Results reveal substantial regional variability in SGE due to differences in management practices. Chemical fertilizers increased emissions by 82%, organic fertilizers by 74%, and their combined use led to stark regional contrasts—rising 610% in Southern China but only 54% in Northwestern China. The effects of tillage, irrigation, and straw incorporation varied based on soil and climate conditions. Highly acidic (pH ≤ 5.5) or alkaline (pH > 8.5) soils significantly altered fertilization effects, while higher SOC levels (>10%) amplified the impact of fertilizers and irrigation. Dry climates generally heightened emissions across management practices, while cold climates exacerbated emissions from organic and combined fertilizers. The study recommends region-specific strategies, including optimizing NPK fertilizer applications (e.g., 180.54–194.02 kg/ha nitrogen in Central China), categorizing organic fertilizer and straw incorporation into four levels, and adopting conventional tillage and controlled irrigation (e.g., in East China) to improve efficiency and sustainability.
The findings align with existing research but challenge the assumption that no-till farming and straw incorporation consistently reduce emissions, underscoring the need for region-specific strategies. Future research should refine soil classification, improve predictive modeling, and integrate carbon sequestration into agricultural management. Policy recommendations include enhancing soil health, optimizing fertilizer use, and adopting controlled irrigation to balance productivity with environmental sustainability.
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Figure | Soil greenhouse gas emissions effect size of various management measures includes TF-NF (Traditional Fertilizer vs. No Fertilizer); TF-CF (Traditional Fertilizer vs. Controlled Fertilizer); CF-NF (Controlled Fertilizer vs. No Fertilizer); OF-NF (Organic Fertilizer vs. No Fertilizer); MOF-MF (Combined Mineral and Organic Fertilizers vs. Mineral Fertilizer); T-NT (Tillage vs. No-Tillage); SR-NSR (Straw Returning vs. No Straw Returning); FI-NI (Flooding Irrigation vs. No Irrigation); and FI-CI (Flooding Irrigation vs. Controlled Irrigation) in agronomic regions including CC (Central China), EC (East China), NC (North China), NEC (Northeast China), NWC (Northwest China), SC (South China), and SWC (Southwest China).
