Nutrient supply enhances positive priming of soil organic C under straw amendment and accelerates the incorporation of straw-derived C into organic C pool in paddy soils

文献类型： 外文期刊

第一作者： Zhang, Yuxuan

作者： Zhang, Yuxuan;Lu, Mengya;Zhang, Bin;Naimaiti, Reziwanguli;Wei, Shangyuan;Ding, Xueli;Wang, Zhiquan;Zhang, Kun

作者机构：

关键词： Straw return; Priming effect; Phospholipid fatty acids; Extracellular enzyme activity; Microbial necromass

期刊名称：EUROPEAN JOURNAL OF SOIL BIOLOGY （ 影响因子：3.3； 五年影响因子：4.1 ）

ISSN： 1164-5563

年卷期： 2024 年 123 卷

页码：

收录情况： SCI

摘要： Straw return accelerates the decomposition of soil organic C (SOC), a phenomenon referred to as the priming effect. However, the interactive influence of nutrient supply levels on priming effect intensity and SOC sequestration in paddy soils still needs to be better understood. In this study, we investigated the dynamics of the priming effect and associated changes in phospholipid fatty acids, enzyme activity, and microbial necromass following the addition of 13C-labelled rice straw (98 % atom) to soils under three nutrient supply levels during a 300-d incubation period. Our results showed that the addition of straw (5 g C kg- 1 soil) with no-nutrient (S + Nu0), low nutrient (S + Nulow, 42 mg N kg- 1, 10 mg P kg- 1), and high nutrient (S + Nuhigh, 126 mg N kg- 1, 30 mg P kg- 1) supply increased total CO2 production by 42.9 %, 59.0 %, and 97.3 %, respectively, compared to the control soil. After 300 d, the cumulative priming effect was nearly doubled in the S + Nulow and tripled in the S + Nuhigh compared to the S + Nu0. Moreover, the intensity of priming varied with the incubation stage under nutrient treatments. Similar patterns of priming effect were observed across all straw amendments during the early incubation stages; however, the priming effect increased with the nutrient supply levels in the later stages. These patterns are linked to microbial metabolic limitation and resource acquisition strategies, as evidenced by a lower C-to-N stoichiometry of extracellular enzymes and necromass in the S + Nulow S + Nuhigh. A greater proportion of straw-derived C incorporation into SOC (indicated by higher levels 13C-SOC) in nutrient-enriched was found, which largely offset the native SOC losses, resulting in high SOC content by the end of incubation. Our findings highlight the critical role of nutrient supply in regulating the priming effect and the balance of SOC after straw return in paddy soils.

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