Straw and nutrients retained in soil are crucial for priming effect (PE) and consequently for soil organic matter (SOM) turnover. However, the mechanisms by which carbon (C), nitrogen (N), and phosphorus (P) and their stoichiometric ratios impact microbial communities and regulate the PE intensity remain controversial, particularly in the flooded rice soils. In this work, the PE dynamics and microbial life strategies were measured over 100 days following an analysis of C:N:P stoichiometry after C labeled straw and nutrient inputs. P was the most limiting nutrient for microorganisms in Straw + N, and soil organic matter (SOM) decomposition was thus reduced by 18%. This was evidenced by: (i) the highest stoichiometric imbalance of C:P (0.97) between available resources and microbial biomass, (ii) the highest dissolved organic C (DOC):Olsen P ratio (140), and (iii) the lowest bacterial abundance. In contrast, lowering the soil C:P ratio (65) under straw + NP accelerated SOM decomposition. Compared to straw + N, the bacterial gene abundance increased by 170% under straw + NP, and the relative abundance of Y-strategists (, , and ) was 6.8 times greater than that of straw + N, suggesting that P was a major limiting factor for microbes in this paddy soil. With the depletion of available C during incubation, bacterial gene abundance decreased for 9 times, and the abundance of decreased from 39% to 19%, the abundance of increased from 20% to 24%, indicating a shift from Y-strategists to A-strategists and acquiring the resources from SOM and inducing positive PE. Our study elucidates the complex and dynamic linkages between C, N and P and their available ratio in resources, and evidence changes in the microbial community structure and PE.

中文翻译：

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化学计量调节稻秆诱导的启动效应：微生物生命策略


保留在土壤中的秸秆和养分对于启动效应（PE）以及土壤有机质（SOM）周转至关重要。然而，碳 (C)、氮 (N) 和磷 (P) 及其化学计量比影响微生物群落和调节 PE 强度的机制仍然存在争议，特别是在淹水水稻土壤中。在这项工作中，在 C 标记的秸秆和养分输入后对 C:N:P 化学计量进行分析后，测量了 100 多天的 PE 动态和微生物生命策略。 P 是秸秆 + N 中微生物最限制的养分，土壤有机质 (SOM) 分解因此减少 18%。这得到了证明：(i) 可用资源和微生物生物量之间 C:P 的最高化学计量不平衡 (0.97)，(ii) 最高的溶解有机 C (DOC):Olsen P 比率 (140)，以及 (iii)细菌丰度最低。相反，在秸秆 + NP 下降低土壤 C:P 比 (65) 加速了 SOM 分解。与秸秆+N相比，秸秆+NP下细菌基因丰度增加了170%，Y策略的相对丰度（、、和）是秸秆+N的6.8倍，表明磷是主要限制因素。稻田土壤中微生物的影响因素。随着培养过程中可用C的消耗，细菌基因丰度下降了9倍，其中α的丰度从39%下降到19%，α的丰度从20%增加到24%，表明从Y-策略转向A-策略策略师并从 SOM 获取资源并诱导正 PE。我们的研究阐明了碳、氮和磷之间复杂而动态的联系及其在资源中的可用比率，以及微生物群落结构和PE的证据变化。