近日，北京大学洪松柏团队研究了1980-2022年中国天然土壤一氧化二氮排放量、分布和时间趋势。相关论文于2025年3月13日发表在《中国科学：地球科学》杂志上。

土壤是全球一氧化二氮（N₂O）排放的最大贡献者。然而，目前的研究工作主要集中在农业土壤中的N₂O排放上，而对另一个重要来源——天然土壤中N₂O排放的研究仍然有限。

在这项研究中，课题组通过机器学习和319个现场观测的新数据集，探索了1980年至2022年期间中国天然土壤N₂O排放的幅度、时空动态和驱动因素。该研究结果表明，与西北部相比，东南部的单位面积N₂O通量普遍较高，森林中的N₂O通量高于草原。这种空间和生物群落异质性受到当地热液条件和氮可用性的强烈调节。在研究期间，N₂O的平均排放量为646.2±27GgN₂Oyr1，森林和草原的贡献大致相等。

此外，从1980年到2022年，其增长趋势显著，增长率为2.7GgN₂Oyr2。这种增长主要是由于森林面积的扩大和氮沉积的增加。该数据驱动研究对中国天然土壤的N₂O排放进行了长期和网格化的估计，强调了未来研究土地利用变化和氮沉降引起的温室气体排放变化的必要性。

附：英文原文

Title: Magnitude, distribution and temporal trend of nitrous oxide emissions from China’s natural soils over 1980–2022

Author: Songbai HONG, Zimeng LI, Mingsong TANG, Fa LI, Yitong YAO, Yanzi YAN, Mingzhu HE, Xuhui WANG, Hui ZENG, Shilong PIAO

Issue&Volume: 2025/03/13

Abstract: Soils represent the largest contributor to global nitrous oxide (N2O) emissions. However, current research efforts predominantly focus on N2O emissions from agricultural soils, while studies on N2O emissions from natural soils, another significant source, remain limited. In this study, we explored the magnitude, spatiotemporal dynamics, and drivers of N2O emissions from China’s natural soils over the period 1980–2022 via machine learning and a compiled novel dataset of 319 field observations. Our results revealed that the N2O flux per unit area was generally higher in the southeast compared to the northwest, and higher in forests than in grasslands. This spatial and biome heterogeneity was strongly regulated by local hydrothermal conditions and nitrogen availability. The averaged N2O emissions over the study period were 646.2±27GgN2Oyr1, with approximately equivalent contributions from forests and grasslands. Moreover, there exhibited a significant and increasing trend from 1980 to 2022, with a rate of 2.7GgN2Oyr2. Such an increase was primarily driven by the expansion of forested area and elevated nitrogen deposition. Our data-driven study presents a long-term and gridded estimate of N2O emissions from China’s natural soils, emphasizing the need for future research on changes of greenhouse gas emissions induced by land use change and nitrogen deposition.

DOI: 10.1007/s11430-024-1522-4

Source: https://www.sciengine.com/10.1007/s11430-024-1522-4