人为的氮输入通过唤醒深层临界区“沉睡”的古碳，增加了全球变暖的潜力，这一成果由河北省土壤生态重点实验室、中国科学院遗传与发育生物学研究所胡春胜的研究组经过不懈努力而取得。相关论文发表在2023年2月8日出版的《科学进展》杂志上。

研究组发现，20年的氮(N)肥使深层临界带富含硝酸盐，土壤有机碳矿化率几乎增加了一倍。这一结果得到了顽固土壤有机碳降解和酶活性的典型功能基因表达的相应增加的支持。二氧化碳的释放和土壤有机碳有类似的¹⁴C的年龄(距今6000-10000年)。研究结果表明，作物施氮可能通过一种以前被忽视的机制，增加二氧化碳从深层临界区排放到大气中。这为显著改善施肥农业土壤氮素管理提供了另一个原因。

据了解，土壤有机碳(SOC)矿化的净增加即使很小，也会导致大气二氧化碳浓度的大幅增加。人们普遍认为，与表层土壤相比，深层临界带(2 ~ 12 m深度)的有机碳矿化速度较慢，受人为扰动的影响较小。

附：英文原文

Title: Anthropogenic N input increases global warming potential by awakening the “sleeping” ancient C in deep critical zones

Author: Shuping Qin, Haijing Yuan, Chunsheng Hu, Xiaoxin Li, Yuying Wang, Yuming Zhang, Wenxu Dong, Timothy Clough, Jiafa Luo, Shungui Zhou, Nicole Wrage-Mnnig, Lin Ma, Oene Oenema

Issue&Volume: 2023-02-08

Abstract: Even a small net increase in soil organic carbon (SOC) mineralization will cause a substantial increase in the atmospheric CO₂ concentration. It is widely recognized that the SOC mineralization within deep critical zones (2 to 12 m depth) is slower and much less influenced by anthropogenic disturbance when compared to that of surface soil. Here, we showed that 20 years of nitrogen (N) fertilization enriched a deep critical zone with nitrate, almost doubling the SOC mineralization rate. This result was supported by corresponding increases in the expressions of functional genes typical of recalcitrant SOC degradation and enzyme activities. The CO₂ released and the SOC had a similar ¹⁴C age (6000 to 10,000 years before the present). Our results indicate that N fertilization of crops may enhance CO₂ emissions from deep critical zones to the atmosphere through a previously disregarded mechanism. This provides another reason for markedly improving N management in fertilized agricultural soils.

DOI: add0041

Source: https://www.science.org/doi/10.1126/sciadv.add0041