Fertilization affects soil microbial community by altering soil organic carbon (C) and nutrients availability. However, it remains unclear how changes in stoichiometric C, N, and P ratios resulting from fertilization affect microbial community. We investigated a 26-year field experiment receiving inorganic fertilizers (N, NP, PK, and NPK), organic N combination (with manure and straw), natural recovery (fallow), and no fertilizer (control). The aim of this study was to explore the responses of microbial community to C: N:P stoichiometry in soil and microbial biomass of topsoil (0–20 cm) and subsoil (20–40 cm). Results showed that compared to control treatment, organic application increased the ratio of fungi to bacteria (F:B) in topsoil and gram-negative bacteria to gram-positive bacteria (G⁻:G⁺) in subsoil. However, application of inorganic decreased both the F: B and G⁻:G⁺ ratio in topsoil. Increasing soil C, N and P availability resulted from inorganic fertilizers and organic combination fertilization caused stoichiometric imbalance between soil and microbial biomass. As a result, the F:B and G⁻:G⁺ ratio were positively related to C:N imbalance but negatively associated with N:P imbalance in topsoil. Redundancy analysis (RDA) showed that main factors regulating microbial community were pH, C:P and N:P imbalances in topsoil, whereas TDN, N:P imbalance, DOC and soil C:N in subsoil. Furthermore, C:P and N:P imbalance explained 16.4% in topsoil, and N:P imbalance explained 22.0% in subsoil of microbial community variation. These results reveal the shifts of soil microbial community are driven by changes in soil pH and C, N and P stoichiometric imbalance from long-term fertilization.

施肥通过改变土壤有机碳 (C) 和养分有效性来影响土壤微生物群落。然而，目前尚不清楚施肥导致的化学计量 C、N 和 P 比率的变化如何影响微生物群落。我们调查了一项为期 26 年的田间试验，该试验使用无机肥料（N、NP、PK 和 NPK）、有机氮组合（肥料和秸秆）、自然恢复（休耕）和不施肥（对照）。本研究的目的是探索微生物群落对土壤中 C:N:P 化学计量以及表土（0-20 cm）和底土（20-40 cm）微生物生物量的响应。结果表明，与对照处理相比，有机施肥增加了表土中真菌与细菌 (F:B) 和革兰氏阴性菌与革兰氏阳性菌的比率 (G ^- :G ⁺) 在地下。然而，施用无机物降低了表土中的 F:B 和 G ^- :G ⁺比率。无机肥料和有机组合施肥导致土壤 C、N 和 P 有效性增加，导致土壤和微生物生物量之间的化学计量失衡。结果，F:B 和 G ⁻ :G ⁺比例与 C:N 失衡呈正相关，但与表土 N:P 失衡呈负相关。冗余分析(RDA)表明，调节微生物群落的主要因素是表层土壤的pH、C:P和N:P失衡，而底土中的TDN、N:P失衡、DOC和土壤C:N是调节微生物群落的主要因素。此外，C:P 和 N:P 失衡解释了表土中 16.4% 的微生物群落变异，而 N:P 失衡解释了底土 22.0% 的微生物群落变异。这些结果表明，土壤微生物群落的变化是由长期施肥引起的土壤 pH 值和 C、N 和 P 化学计量失衡的变化驱动的。