Chemical fertilizers are often used in managed grasslands to alleviate nutrient deficiency, especially for nitrogen (N) and phosphorus (P), and to maximize plant production. Soil microbial communities can respond to N/P fertilization-induced changes in soil environmental variables, like increased N availability or soil acidification, and to fertilization-induced changes in plant species richness which can determine the diversity of niches available for microbial taxa. Thus, analyzing the concurrent responses of soil environmental variables and of plant and soil microbial diversity is needed to understand the effect of N/P fertilization on soil microbial communities. Here we investigated the effects of different N, P and NP fertilization treatments (4 N levels without P; 4 P levels without N; and 4 P levels with constant N addition) on the communities of plants and of soil ammonia-oxidizing archaea and bacteria (AOA and AOB, respectively). AOA and AOB community compositions were more sensitive to NP and N fertilization, respectively. Simple regressions and structural equation modeling demonstrate that AOA richness was correlated, though weakly, to plant species richness rather than to soil environmental variables. AOB richness was mostly correlated with plant richness and soil available P. This study demonstrates that plant richness is an important determinant of AOA and AOB richness, and helps understanding the ecology of soil ammonia oxidizers in the context of altered phosphorus and nitrogen availabilities.

化肥通常用于有管理的草原，以减轻营养素的缺乏，尤其是氮（N）和磷（P）的营养不足，并最大程度地提高植物的产量。土壤微生物群落可以响应氮磷肥引起的土壤环境变量的变化（例如增加的氮素利用率或土壤酸化），也可以响应由肥料引起的植物物种丰富度的变化，这些变化可以确定微生物分类单元可用的生态位的多样性。因此，需要分析土壤环境变量以及植物和土壤微生物多样性的同时响应，以了解氮磷肥对土壤微生物群落的影响。在这里，我们研究了不同的氮，磷和NP施肥处理的效果（4个氮水平不含磷； 4个磷水平不含氮； 4个氮水平不含氮； 4个氮水平不含氮）。在植物群落上以及土壤中的氨氧化古细菌和细菌（分别为AOA和AOB）和4 P水平（恒定添加N）。AOA和AOB群落组成分别对NP和N受精更为敏感。简单的回归分析和结构方程模型表明，AOA的丰富度与植物物种的丰富度而不是土壤环境变量相关，尽管程度较弱。AOB的丰富度主要与植物的丰富度和土壤有效磷相关。这项研究表明，植物的丰富度是AOA和AOB丰富度的重要决定因素，并有助于在磷和氮利用率改变的情况下理解土壤氨氧化剂的生态。AOA和AOB群落组成分别对NP和N受精更为敏感。简单的回归分析和结构方程模型表明，AOA的丰富度与植物物种的丰富度而不是土壤环境变量相关，尽管程度较弱。AOB的丰富度主要与植物的丰富度和土壤有效磷相关。这项研究表明，植物的丰富度是AOA和AOB丰富度的重要决定因素，并有助于在磷和氮利用率改变的情况下理解土壤氨氧化剂的生态。AOA和AOB群落组成分别对NP和N受精更为敏感。简单的回归分析和结构方程模型表明，AOA的丰富度与植物物种的丰富度而不是土壤环境变量相关，尽管程度较弱。AOB的丰富度主要与植物的丰富度和土壤有效磷相关。这项研究表明，植物的丰富度是AOA和AOB丰富度的重要决定因素，并有助于在磷和氮利用率改变的情况下理解土壤氨氧化剂的生态。