Research Center on Ecological Sciences, Jiangxi Agricultural University, Nanchang, 330045, China.
Research Center on Ecological Sciences, Jiangxi Agricultural University, Nanchang, 330045, China.
J Environ Manage. 2024 Sep;367:121927. doi: 10.1016/j.jenvman.2024.121927. Epub 2024 Jul 29.
Given the significance of nitrogen (N) as the most constraining nutrient in agro-ecosystems, it is crucial to develop an updated model for N fertilizers management to achieve higher crop yields while minimizing the negative impacts on the environment. Coated urea is touted as one of the most important controlled-release N fertilizers used in agriculture to reduce cropland emissions and improve nitrogen use efficiency (NUE) for optimal crop yields. The sustainability of coated urea depends on the trade-offs between crop productivity, NUE and greenhouse gas emissions (CO, CH and NO); however, role of various agro-edaphic factors in influencing these trade-offs remains unclear. To determine the effects of soil properties, climatic conditions, experimental conditions, and type of coated urea on greenhouse gas emissions, NH losses, crop productivity, and NUE, we conducted a meta-analysis using data from 76 peer-reviewed studies. Our results showed that the application of coated urea under field conditions contributed to a greater reduction in NO emissions (-48.67%) and higher NUE (58.72%), but crop yields were not significant. Across different climate regions, subtropical monsoon climate showed a perceptible mitigation for CO, CH and NH (-78.38%; -83.33%; -27.46%), while temperate climate reduced NO emissions by -70.36%. For different crops, only rice demonstrated reduction in CO, CH, NO and NH losses. On the other hand, our findings revealed a mitigating trade-off between CO and CH emissions on medium-textured soils and NO emissions on fine-textured soils. A significant reduction in NO and NH losses was evident when coated urea was applied to soils with a pH > 5.5. Interestingly, application of coated urea to soils with higher C/N ratios increased NH losses but showed a noticeable NO reduction. We found that polymer-coated urea reduced CH and NO emissions and NH losses at the expense of higher CO emissions. Moreover, application of a lower dose of coated urea (0-100 kg N ha) enhanced CO and CH mitigation, while NO mitigation increased linearly with increasing dose of coated urea. Most importantly, our results showed that the application of coated urea leads to a large mismatch between NUE, crop yields and greenhouse gas mitigation. By and large, the application of coated urea did not correspond with higher crop yields despite significant reduction in the emissions and improved NUE. Overall, these results suggest that site-specific agro-edaphic conditions should be considered when applying coated urea to reduce these emissions and N volatilization losses for increasing NUE and crop yields.
鉴于氮（N）作为农业生态系统中最具限制性的养分的重要性，开发一种更新的氮肥管理模型至关重要，以实现更高的作物产量，同时最大限度地减少对环境的负面影响。包膜尿素被吹捧为农业中最重要的控释氮肥之一，用于减少农田排放并提高氮利用效率（NUE）以实现最佳作物产量。包膜尿素的可持续性取决于作物生产力、NUE 和温室气体排放（CO、CH 和 NO）之间的权衡；然而，各种农业土壤因素在影响这些权衡方面的作用尚不清楚。为了确定土壤特性、气候条件、实验条件和包膜尿素类型对温室气体排放、NH 损失、作物生产力和 NUE 的影响，我们使用 76 篇同行评议研究的数据进行了荟萃分析。我们的结果表明，在田间条件下应用包膜尿素有助于更大程度地减少 NO 排放（-48.67%）和提高 NUE（58.72%），但对作物产量没有显著影响。在不同的气候区，亚热带季风气候对 CO、CH 和 NH 的减排效果明显（-78.38%；-83.33%；-27.46%），而温带气候则减少了-70.36%的 NO 排放。对于不同的作物，只有水稻表现出 CO、CH、NO 和 NH 损失的减少。另一方面，我们的研究结果揭示了中质地土壤上 CO 和 CH 排放与 NO 排放之间以及细质地土壤上 NH 损失与 NO 排放之间的权衡关系。当包膜尿素施用于 pH 值大于 5.5 的土壤时，NO 和 NH 损失显著减少。有趣的是，当包膜尿素施用于 C/N 比更高的土壤时，NH 损失增加，但 NO 明显减少。我们发现聚合物包膜尿素以增加 CO 排放为代价减少 CH 和 NO 排放和 NH 损失。此外，应用较低剂量的包膜尿素（0-100kgNha）可增强 CO 和 CH 的缓解效果，而随着包膜尿素剂量的增加，NO 的缓解效果呈线性增加。最重要的是，我们的研究结果表明，包膜尿素的应用导致 NUE、作物产量和温室气体减排之间存在很大的不匹配。总的来说，尽管排放和 NUE 显著减少，但包膜尿素的应用并没有带来更高的作物产量。总体而言，这些结果表明，在应用包膜尿素减少这些排放和氮挥发损失以提高 NUE 和作物产量时，应考虑特定地点的农业土壤条件。
