Influence of soil N availability on priming effects depending on temperature

文献类型： 外文期刊

第一作者： Cui, Jun

作者： Cui, Jun;Cui, Jun;Wei, Liang;Zhu, Zhenke;Kuzyakov, Yakov;Ge, Tida;Deng, Yangwu;Chen, Song;Kuzyakov, Yakov

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关键词： Priming effect; Temperature gradient (15 degrees C 25 degrees C And 35 degrees C); Soil N availability; C and N limitations; Microbial life strategy

期刊名称：SOIL & TILLAGE RESEARCH （ 影响因子：6.8； 五年影响因子：7.8 ）

ISSN： 0167-1987

年卷期： 2024 年 242 卷

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收录情况： SCI

摘要： The priming effect (PE) is a globally important regulator of soil organic matter (SOM) turnover that closely correlates with N availability. PE intensity is usually higher under N-limited conditions and lower under N inputs, but this relationship may depend on temperature. To investigate whether temperature influences the role of N availability in the PE, we conducted a 200-d incubation of soil samples amended with C-13-labeled rice litter at 15 degrees C, 25 degrees C, and 35 degrees C, adding NH4+ and NO3- to examine impacts of increased N availability on PE. Litter amendment caused net N immobilization and exacerbated soil N limitation, thereby reducing SOM mineralization (which was negative PE) at 25 degrees C and 35 degrees C. N addition mitigated the negative PE intensity, with a marked decrease at 25 degrees C (from -21 % to -5 %) and a marginal impact at 35 degrees C. Microbial biomass C and N contents peaked at 25 degrees C but declined by similar to 20 % at 35 degrees C. The ratio of C- to N-acquiring enzyme activities, as well as that for gene copies, was lower at 25 degrees C than at 35 degrees C, suggesting N limitation at 25 degrees C. In contrast, rapid labile C depletion and high microbial metabolic quotient caused severe microbial C limitation at 35 degrees C, which forced microorganisms to increase abundance of genes involved in recalcitrant compound decomposition. Warming to 35 degrees C also shifted microbial communities from the dominance of r-strategists (25 degrees C) to that of K-strategists (35 degrees C), as indicated by increases in the ratio of K- to r-related functional genes. The dominance of K-strategists, which generally have low N demands, rendered PE less sensitive to N inputs at 35 degrees C. Our findings underscore the temperature-dependent nature of soil N versus C limitations, which may lead to lower microbial N limitation and decreased impact of N availability on PE under a warming climate.

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