Nitrogen-induced acidification increases soil organic carbon accrual by promoting particulate organic carbon and microbial necromass under long-term experiments in the paddy soils of East China

文献类型： 外文期刊

第一作者： Chen, Zhaoming

作者： Chen, Zhaoming;Wang, Qiang;Ma, Jinchuan;Wang, Feng;Ma, Junwei;Ye, Jing;Zou, Ping;Sun, Wanchun;Yu, Qiaogang

作者机构：

关键词： Nitrogen fertilization; Mineral-associated organic carbon; Microbial necromass; Particulate organic carbon; Paddy soil

期刊名称：PLANT AND SOIL （ 影响因子：4.1； 五年影响因子：4.7 ）

ISSN： 0032-079X

年卷期： 2025 年

页码：

收录情况： SCI

摘要： Background and aimsNitrogen (N) addition can substantially affect soil carbon cycling in agroecosystems. Microbial necromass carbon (MNC) is widely recognized as a key contributor to soil organic C (SOC) fractions. However, the mechanisms underlying the responses of MNC and SOC fractions to N fertilization in paddy soils remain unclear.MethodsA field experiment with four N rates, namely, 0, 300, 450, and 600 kg N ha-1 yr-1 was conducted to determine the effects of N addition on SOC fractions, soil microbial necromass carbon (MNC), enzyme activity, and microbial biomass in paddy soils with rice-wheat rotation.ResultsN addition increased SOC and POC concentrations by 2.88-8.41% and 14.6-41.2%, respectively, but did not affect MAOC. The ratio of MAOC to POC was reduced by N addition, indicating that N addition decreased SOC stability. N addition increased MNC concentration by 7.32-22.5% and its contribution to SOC by 4.14-13.7%. The activity of beta-1,4-N-acetyl-glucosaminidase was decreased, while the activities of leucine amino peptidase and acid phosphatase were increased under N addition. Structural equation modeling and random forest revealed that N-induced decrease in soil pH promoted the accrual of MNC by increasing root and microbial biomass, consequently improving POC.ConclusionsPOC is likely more vulnerable to N addition than MAOC. N-induced acidification is the primary driver for promoting SOC accrual by increasing POC in paddy soils.

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