College of Resources and Environmental Sciences, National Academy of Agriculture Green Development, Key Laboratory of Plant-Soil Interactions, Ministry of Education, Key Laboratory of Low-carbon Green Agriculture, Ministry of Agriculture and Rural Affairs, China Agricultural University, Beijing, 100193, China.
Cultivated Land Quality Monitoring and Protection Center, Ministry of Agriculture and Rural Affairs, China.
Sci Total Environ. 2023 Feb 1;858(Pt 2):159738. doi: 10.1016/j.scitotenv.2022.159738. Epub 2022 Nov 2.
Nitrous oxide (NO), as a potent greenhouse gas, must be limited to prevent the global temperature increasing by >2 °C. Cropland is the largest source of anthropogenic NO emissions; however, earlier estimates for emissions and their exceedances still remain uncertainties. Here, we used a spatially explicit model to estimate cropland NO emission in 2014 by refined grid-level crop-specific EFs and considered the background emission. We also sought to determine where NO emissions exceed the "boundary" through analysis of spatial data from representative concentration pathway (RCP) 2.6. The global cropland NO emission was 2.92 ± 0.59 Tg N yr, which far exceeds the 0.82 Tg N yr boundary, over 90 % of cropland areas exceeded the boundary. Western Europe, Southeastern China, Pakistan, and the Ganges Plain exceeded the boundary by >2 kg N ha yr. The boundary exceedances showed a positive linear response with respect to total cropland emission and a quadratic response to GDP per capita at the country level. Our study highlights the necessity of accurate estimations of spatial variations in cropland NO emissions and evaluation of exceedances, to facilitate the development of more effective mitigation measures in different regions.
一氧化二氮（NO）作为一种强效温室气体，必须加以限制，以防止全球气温升高超过 2°C。农田是人为 NO 排放的最大来源；然而，早期对排放及其超标量的估计仍然存在不确定性。在这里，我们使用一个空间明确的模型，通过细化的网格级作物特定排放因子来估算 2014 年农田 NO 排放，并考虑了背景排放。我们还试图通过分析代表性浓度途径（RCP）2.6 的代表性空间数据来确定 NO 排放在哪里超过“边界”。全球农田 NO 排放量为 2.92 ± 0.59Tg N yr，远远超过 0.82Tg N yr 的边界，超过 90%的农田面积超过了边界。西欧、中国东南部、巴基斯坦和恒河平原的 NO 排放量超过了边界>2kg N ha yr。边界超标量与农田总排放量呈正线性响应，与国家层面的人均 GDP 呈二次响应。我们的研究强调了准确估算农田 NO 排放的空间变化和评估超标量的必要性，以促进在不同地区制定更有效的缓解措施。
