Abstract The nitrogen (N) cycle process in agricultural soil is affected by fertilization. However, there is limited information on the abundance of N-cycling microbial community and its response to the different fertilization strategies in acidic soil. Using quantitative PCR, we investigated the microbial abundance involving 11 functional genes of the N cycle (nifH, chiA, aprA, archaeal and bacterial amoA, napA, narG, nirS, nirK, norB and nosZ) in an acidic agricultural soil. The soils were subjected to no fertilizer (Control), chemical NPK fertilizer (NPK), NPK combined with quicklime (NPKCa), NPK combined with crop residues (NPKS), NPK combined with quicklime and crop residues (NPKSCa), NPK combined with manure (NPKM) and only manure (M) fertilization for 27 years. Results showed that fertilization improved crop yield and soil nutrient availability, changed soil pH levels and affected the abundance of N-cycling functional genes. Manure application markedly increased the abundance of all genes and was associated with the largest shift in community structure. The variation of microbial community in the fertilization treatments (NPK, NPKCa, NPKS, NPKSCa, M and NPKM) resulted from the distinct contribution of functional genes, in which the nifH, napA and archaeal amoA genes highly contributed to the community variations between manure fertilization and Control. Soil variables, particularly pH, NO3−-N and AP, significantly affected the N-cycling microbial community structure. Overall, the different fertilization strategies demonstrated varying influential patterns on the N-cycling microbial abundance and community by altering soil properties and affecting specific functional gene abundance; in particular, manure treatments had a greater influence compared to chemical fertilizers.

中文翻译：

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施肥策略影响酸性农业土壤中土壤性质和氮循环功能基因的丰度

摘要 农业土壤中氮（N）循环过程受施肥影响。然而，关于 N 循环微生物群落的丰度及其对酸性土壤中不同施肥策略的响应的信息有限。我们使用定量 PCR 研究了酸性农业土壤中涉及 N 循环的 11 个功能基因（nifH、chiA、aprA、古细菌和细菌 amoA、napa、narG、nirS、nirK、norB 和 nosZ）的微生物丰度。土壤分别施不施肥料（对照）、化学氮磷钾肥（NPK）、氮磷钾与生石灰（NPKCa）、氮磷钾与作物残茬（NPKS）、氮磷钾与生石灰和农作物残茬（NPKSCa）、氮磷钾与粪肥混合(NPKM) 和仅肥料 (M) 施肥 27 年。结果表明，施肥提高了作物产量和土壤养分有效性，改变了土壤 pH 值，并影响了 N 循环功能基因的丰度。施肥显着增加了所有基因的丰度，并与群落结构的最大转变有关。施肥处理（NPK、NPKCa、NPKS、NPKSCa、M 和 NPKM）中微生物群落的变化是由于功能基因的显着贡献，其中 nifH、napa 和古菌 amoA 基因对粪便施肥之间的群落变异贡献很大和控制。土壤变量，特别是 pH、NO3--N 和 AP，显着影响 N 循环微生物群落结构。全面的，不同的施肥策略通过改变土壤特性和影响特定功能基因丰度，对氮循环微生物丰度和群落表现出不同的影响模式；特别是，与化肥相比，粪便处理的影响更大。