Abstract Ammonia oxidation, the rate-limiting step of autotrophic nitrification, is carried out by ammonia-oxidizing archaea (AOA) and bacteria (AOB) that differ in their physiology and metabolic pathways. However, there has been little field investigations on the dynamic responses of ammonia oxidizers to different fertilizer inputs in intensive crop rotations. Here, we examine the soil potential nitrification rates (PNR), abundance and communities of AOB and AOA across different growth stages of wheat and maize at two soil depths (0–20 and 20–40 cm) under three fertilization regimes, namely zero fertilization (CK), chemical fertilizer (NPK) and partial replacement of the chemical fertilizer nutrients with organic manure (NPKM). Soil PNR was higher in the surface soil than in the subsoil in the wheat season, but no significant difference was observed in the maize season. Fertilization especially NPK treatment increased soil PNR, and the effect was more pronounced in the surface soil in the wheat season. The influence of soil depth on the abundance and communities of AOA and AOB was greater than that of fertilizer regime or plant growth stage across wheat and maize growth stages. The differences of ammonia oxidizers communities were mainly attributable to soil total nitrogen, organic carbon and soil moisture contents in the two depths. The abundance of AOB decreased more sharply than that of AOA with increasing soil depth. In general, application of NPK only increased AOB abundance in both wheat and maize seasons, whereas NPKM treatment increased AOB abundance only in the maize season (except in the subsoil at harvest). Generally, soil PNR was correlated with AOB and AOA abundances except for AOB in the subsoil in the wheat season and AOA in the surface soil during maize growth. Fertilization regime did not increase AOA abundance or alter AOA communities across all soil depths and plant growth stages. Our results indicate that the ammonia oxidizers differ greatly in responses to fertilization regimes and the changes are associated with soil depth and crop growth stage. The dynamics of soil microorganisms should be integrated into fertilizer and crop management to achieve sustainable agricultural systems.

中文翻译：

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集约化管理农业土壤中氨氧化剂对不同施肥投入的响应动态

摘要 氨氧化是自养硝化作用的限速步骤，由生理学和代谢途径不同的氨氧化古细菌 (AOA) 和细菌 (AOB) 进行。然而，很少有关于氨氧化剂在集约化轮作中对不同肥料投入的动态响应的实地调查。在这里，我们检查了小麦和玉米在两种土壤深度（0-20 和 20-40 厘米）在三种施肥方式下，即零施肥的不同生长阶段的土壤潜在硝化率（PNR）、丰度和 AOB 和 AOA 群落(CK)、化肥 (NPK) 和有机肥 (NPKM) 部分替代化肥养分。小麦季节表层土壤的土壤 PNR 高于底土，但在玉米季节没有观察到显着差异。施肥特别是NPK处理提高了土壤PNR，且在小麦季节在表层土壤中效果更为明显。在小麦和玉米生长阶段，土壤深度对 AOA 和 AOB 丰度和群落的影响大于施肥制度或植物生长阶段。氨氧化菌群落的差异主要归因于两个深度的土壤全氮、有机碳和土壤水分含量。随着土壤深度的增加，AOB 的丰度下降幅度大于 AOA。一般而言，NPK 的施用仅增加小麦和玉米季节的 AOB 丰度，而 NPKM 处理仅在玉米季节增加 AOB 丰度（收获时的底土除外）。一般来说，土壤 PNR 与 AOB 和 AOA 丰度相关，除了小麦季节底土中的 AOB 和玉米生长期间表层土壤中的 AOA。施肥制度没有增加 AOA 丰度或改变所有土壤深度和植物生长阶段的 AOA 群落。我们的结果表明氨氧化剂对施肥制度的反应差异很大，并且这些变化与土壤深度和作物生长阶段有关。应将土壤微生物的动态整合到肥料和作物管理中，以实现可持续的农业系统。我们的结果表明氨氧化剂对施肥制度的反应差异很大，并且这些变化与土壤深度和作物生长阶段有关。应将土壤微生物的动态整合到肥料和作物管理中，以实现可持续的农业系统。我们的结果表明氨氧化剂对施肥制度的反应差异很大，并且这些变化与土壤深度和作物生长阶段有关。应将土壤微生物的动态整合到肥料和作物管理中，以实现可持续的农业系统。