Microbial stoichiometry is pivotal in the soil elements cycle within terrestrial ecosystems. However, the impact of microbial stoichiometry on the phosphorus (P) pool transformation in low-P paddy soil, especially with manure addition, remains poorly understood. This study aimed to elucidate the response mechanism of microbial stoichiometry in regulating P pool transformation in two low-P paddy soils during a 60-day flooding-drought incubation. The results demonstrated that pig manure and vermicompost application significantly increased soil Olsen-P by 202–309 %, and microbial biomass P (MBP) by 54.4–79.3 % compared to no fertilization. Additionally, vermicompost treatment increased moderately labile organic P (MLP) by 133–257 % and decreased fulvic acidassociated organic P (FAP) by 10.5–25.4 % in Acrisol-flooding, Acrisol-drought, and Ultisol-drought, indicating that manure application improved the transformation of FAP to MLP. The microbial biomass carbon (MBC)/MBP ratio was lowest under Acrisol-flooding and highest under Ultisol-drought, suggesting that microorganisms adjust high ratios for stoichiometric stability and enhanced MBP utilization under deficient resource conditions. Manure treatments increased alkaline phosphatase (ALP) by 5.33–12.9 % under flooding conditions, indicating microorganisms facilitate the mineralization of soil organic P (P). Compared to Acrisol-flooding, both ALP and β-1,4-glucosidase (BG) significantly increased by 103 % and 259 %, respectively, under Ultisol-drought, along with a positive correlation between BG and MLP, implying that microorganisms enhance soil organic matter mineralization in resource-limited conditions by increasing C-acquiring enzymes and releasing P. Additionally, the microbial community composition shifted from -strategists to -strategists, primarily by decreasing Proteobacteria and increasing Acidobacteria under resource deficiency and drought. The -strategists directly mineralize P by maintaining a low MBC/MBP and high ALP, while -strategists indirectly mineralize P by maintaining a high MBC/MBP and high BG. The findings suggest that manure application altered the resource status of low-P paddy soils, changed microbial stoichiometry, and influenced soil P availability through adjustments in microbial activity and extracellular enzyme production.

中文翻译：

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肥料施用影响微生物化学计量并改变微生物生活策略以调节低磷水稻土中磷的生物有效性


微生物化学计量在陆地生态系统内的土壤元素循环中至关重要。然而，微生物化学计量对低磷水稻土中磷（P）库转化的影响，特别是添加肥料的影响，仍然知之甚少。本研究旨在阐明微生物化学计量对两种低磷水稻土在60天的旱涝培育过程中调节磷库转化的响应机制。结果表明，与不施肥相比，施用猪粪和蚯蚓粪可使土壤奥尔森磷显着增加 202-309%，微生物生物量磷 (MBP) 增加 54.4-79.3%。此外，在 Acrisol 水淹、Acrisol 干旱和 Ultisol 干旱中，蚯蚓堆肥处理使中度不稳定有机磷 (MLP) 增加 133–257%，使黄腐酸相关有机磷 (FAP) 减少 10.5–25.4%，这表明粪肥施用有所改善FAP到MLP的转变。微生物生物量碳 (MBC)/MBP 比率在 Acrisol 驱油条件下最低，在 Ultisol 干旱条件下最高，表明微生物在资源匮乏的条件下调整高比率以实现化学计量稳定性并提高 MBP 利用率。在洪水条件下，粪肥处理使碱性磷酸酶（ALP）增加了 5.33-12.9%，表明微生物促进了土壤有机磷（P）的矿化。与 Acrisol 驱相比，Ultisol 干旱下 ALP 和 β-1,4-葡萄糖苷酶 (BG) 分别显着增加 103% 和 259%，并且 BG 和 MLP 之间呈正相关，这意味着微生物增强了土壤通过增加 C 获取酶和释放 P，在资源有限的条件下有机质矿化。 此外，微生物群落组成从“战略型”转变为“战略型”，主要是在资源匮乏和干旱的情况下，变形菌门减少，酸杆菌门增加。 -策略者通过维持低MBC/MBP和高ALP来直接矿化P，而-策略者通过维持高MBC/MBP和高BG来间接矿化P。研究结果表明，粪肥施用改变了低磷水稻土的资源状况，改变了微生物化学计量，并通过调整微生物活性和细胞外酶的产生来影响土壤磷的有效性。