Meng Xuanchen, Meng Fanxiang, Chen Peng, Hou Dingmu, Zheng Ennan, Xu Tianyu
School of Hydraulic and Electric Power, Heilongjiang University, Harbin 150080, China.
College of Agricultural Science and Engineering, Hohai University, Nanjing 210098, China.
Sci Total Environ. 2024 Dec 1;954:176315. doi: 10.1016/j.scitotenv.2024.176315. Epub 2024 Sep 19.
Conservation tillage practices, including reduced tillage (RT), no-tillage (NT) and straw return (SR), have been widely adopted to enhance soil organic carbon density (PSOC) and improve the soil quality while mitigating the negative environmental impacts of intensive farming. However, current studies on the effects of these practices on SOC sequestration and NO flux show considerable variability, making it challenging to draw definitive conclusions about the individual and combined impacts of conservation tillage practices and introducing substantial uncertainty in estimating the agricultural sector's potential to mitigate climate change. To address this gap, we conducted a meta-analysis of 902 pairwise comparisons from 90 peer-reviewed publications to evaluate the effects of five conservation tillage practices (straw return (SR), reduced tillage (RT), no-tillage (NT), straw return combined with tillage reduction (SR + RT) and straw returning combined with no-tillage (SR + NT)) on C sequestration and NO emissions from agricultural soils. The results show that SR was the most effective practice for increasing SOC content (23.7 %), followed by RT + SR (5.5 %) and NT + SR (4.4 %). Additionally, RT (12.3 %) and NT (14.3 %) significantly reduced soil NO emissions. This study also identified key drivers, including climatic factors, soil properties, and agricultural management practices, that influence SOC content and NO emissions under different conservation tillage practices. For example, the mean annual precipitation, mean annual temperature, soil type, pH, soil total nitrogen content, N application rate, and experiment duration were identified as the key factors affecting SOC content and NO emissions Specifically, suitable temperature, lower rainfall and alkaline soil environment significantly enhanced the C sequestration efficiency of SR, while suitable climatic conditions and soil texture combined with an alkaline environment contributed to a significant reduction in long-term NT soil NO emissions. These results provide a robust scientific foundation for the strategic implementation of conservation tillage to reduce greenhouse gas emissions, mitigate global warming, and enhance soil C sequestration capacity.
保护性耕作措施，包括少耕（RT）、免耕（NT）和秸秆还田（SR），已被广泛采用，以提高土壤有机碳密度（PSOC）、改善土壤质量，同时减轻集约农业对环境的负面影响。然而，目前关于这些措施对土壤有机碳固存和氮通量影响的研究结果差异很大，因此难以就保护性耕作措施的单独和综合影响得出明确结论，并且在估算农业部门缓解气候变化的潜力时引入了很大的不确定性。为了填补这一空白，我们对90篇同行评议出版物中的902对比较进行了荟萃分析，以评估五种保护性耕作措施（秸秆还田（SR）、少耕（RT）、免耕（NT）、秸秆还田与少耕结合（SR + RT）以及秸秆还田与免耕结合（SR + NT））对农业土壤碳固存和氮排放的影响。结果表明，秸秆还田是增加土壤有机碳含量最有效的措施（23.7%），其次是少耕加秸秆还田（5.5%）和免耕加秸秆还田（4.4%）。此外，少耕（12.3%）和免耕（14.3%）显著降低了土壤氮排放。本研究还确定了影响不同保护性耕作措施下土壤有机碳含量和氮排放的关键驱动因素，包括气候因素、土壤性质和农业管理措施。例如，年平均降水量、年平均温度、土壤类型、pH值、土壤全氮含量、施氮量和试验持续时间被确定为影响土壤有机碳含量和氮排放的关键因素。具体而言，适宜的温度、较低的降雨量和碱性土壤环境显著提高了秸秆还田的碳固存效率，而适宜的气候条件、土壤质地与碱性环境相结合，有助于长期免耕土壤的氮排放显著减少。这些结果为战略性实施保护性耕作以减少温室气体排放、缓解全球变暖以及增强土壤碳固存能力提供了坚实的科学基础。
