Aims Although phosphorus (P) availability and plant cultivation affect diazotrophic populations, studies often consider individual factors rather than their combined effects. Their relative importance to diazotrophs remains poorly understood, especially in acidic soils with P deficiency. It is hypothesized that the influences of P fertilization and plant cultivation on diazotrophic communities differ in acidic soils. The objectives were to investigate these influences and identify the key determining factors. Methods Maize was grown in an acidic soil that was supplemented with 0, 20, and 50 mg P kg − 1 for 42 days. Maize biomasses, plant nutrient contents, and soil physicochemical properties were determined. Based on the nifH gene, the abundances and community compositions of diazotrophs in the different plant/soil compartments (bulk soils, rhizosphere soils, and roots) were respectively investigated using quantitative PCR and high-throughput sequencing. Results P fertilization significantly improved the diazotrophic abundances in the bulk and rhizosphere soils, but not in the roots. The plant/soil compartments had stronger effects on the abundance and diversity of diazotrophs than did P fertilization. Furthermore, the plant/soil compartments influenced diazotrophic community composition, but P fertilization did not. However, in the same sampling site, P fertilization caused community variations in the bulk and rhizosphere soils, rather than in the roots. Conclusions Although P fertilization affected the abundances and compositions of diazotrophic communities in the bulk and rhizosphere soils, the plant/soil compartments resulting from maize cultivation had more noticeable effects than did P fertilization. These findings improved the understanding of biological nitrogen fixation in acidic soils.

中文翻译：

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固氮群落对玉米种植比酸性土壤中的磷肥更敏感

目的 尽管磷 (P) 可用性和植物栽培会影响固氮种群，但研究通常考虑单个因素而不是它们的综合影响。它们对固氮菌的相对重要性仍然知之甚少，尤其是在缺磷的酸性土壤中。假设在酸性土壤中施磷和植物栽培对固氮群落的影响不同。目标是调查这些影响并确定关键的决定因素。方法 玉米在添加了 0、20 和 50 mg P kg - 1 的酸性土壤中生长 42 天。测定了玉米生物量、植物养分含量和土壤理化特性。基于 nifH 基因，不同植物/土壤区室（大块土壤、根际土壤和根）分别使用定量 PCR 和高通量测序进行研究。结果磷肥显着提高了块体和根际土壤中的固氮丰度，但在根中没有显着改善。与施磷相比，植物/土壤区室对固氮菌的丰度和多样性的影响更大。此外，植物/土壤区室影响固氮群落组成，但施磷没有影响。然而，在同一采样点，磷肥导致了大块土壤和根际土壤的群落变化，而不是根部。结论 尽管施磷影响了大块土壤和根际土壤中固氮群落的丰度和组成，由玉米种植产生的植物/土壤区室比施磷具有更显着的影响。这些发现提高了对酸性土壤中生物固氮的理解。