Microorganisms maintain C:N stoichiometric balance by regulating the priming effect in long-term fertilized soils

文献类型： 外文期刊

第一作者： Zhu, Zhenke

作者： Zhu, Zhenke;Zhou, Juan;Liu, Shoulong;Yuan, Hongzhao;Zhou, Ping;Wu, Jinshui;Ge, Tida;Zhu, Zhenke;Zhou, Juan;Liu, Shoulong;Yuan, Hongzhao;Zhou, Ping;Wu, Jinshui;Ge, Tida;Zhou, Juan;Wu, Jinshui;Shahbaz, Muhammad;Tang, Haiming;Zhang, Wenju;Alharbi, Hattan;Kuzyakov, Yakov;Kuzyakov, Yakov;Kuzyakov, Yakov

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关键词： Microbial C:N imbalance; Enzyme activity; Long-term fertilization; Stoichiometric homeostasis; Soil organic C mineralization

期刊名称：APPLIED SOIL ECOLOGY （ 影响因子：4.046； 五年影响因子：4.884 ）

ISSN： 0929-1393

年卷期： 2021 年 167 卷

页码：

收录情况： SCI

摘要： Labile carbon (C) inputs affect the soil carbon:nitrogen (C:N) ratio and microbial stoichiometric homeostasis, which control the intensity and direction of the priming effect (PE). Here, we clarified how soil microorganisms regulate enzyme production and PE to maintain the C:N stoichiometric balance. Specifically, we conducted an incubation experiment by adding C-13-labeled glucose to four long-term fertilized paddy soils: no fertilization; fertilization with mineral nitrogen, phosphorus, and potassium (NPK); NPK combined with straw; and NPK with manure (NPKM). After glucose addition, the dissolved organic carbon-to-ammonium (DOC:NF4+) ratio (24-39) initially increased, but subsequently decreased after day 2 following glucose exhaustion. In parallel, the microbial C:N imbalance [(DOC:NH4+):(microbial biomass C:microbial biomass N)] rapidly decreased from day 2 (4.6-7.2) to day 20 (<0.5). Thus, microorganisms became C limited after 20 days of incubation. Excess C, resulting from glucose addition, increased N-hydrolase (chitinase) production and N mining from soil organic matter (SOM) through positive PEs. However, C hydrolase beta-1,4-glucosidase and beta-xylosidase) activity increased, while that of N hydrolase (chitinase) decreased, following glucose exhaustion. Consequently, the C:N microbial biomass ratio increased as the DOC:NH4+ ratio decreased, leading to negative PEs. NPKM-fertilized soil had the largest cumulative PE (2.3% of soil organic carbon) because it had the highest microbial biomass and iron (Fe) reduction rate. Thus, this increased N mining from SOM maintained the microbial C:N stoichiometric balance. We concluded that soil microorganisms regulate C- and N-hydrolase production to control the intensity and direction of PE, maintaining the C:N stoichiometric balance in response to labile C inputs.

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