Abstract The Northern Great Plains of the United States and Canada have seen an increase in pulse crops like pea, lentil, and chickpea acreage in dryland and irrigated systems. Rotating pulse crops into cereal crop production systems could reduce the demand for nitrogen fertilizer due to the symbiotic relationship with nitrogen fixing bacteria called diazotrophs. Legume-diazotroph relationships are well studied, but little is known about the free-living bacteria of the bulk soil in the legume-cereal rotation systems. Here we determine the community structure of the overall (16S) and diazotroph (nifH) soil microbiome in pulse-cereal rotations across the state of Montana. Many variables influenced the microbial community structure, but and among them, irrigation caused a significant shift in the composition of the communities and co-occurrence network topology. Interestingly, the diazotrophic communities in dryland soil are more robust and contain more generalist compared to irrigated soils. Co-occurrence networks support the identification of different diazotrophic keystone taxa such as Firmicutes in irrigated and Proteobacteria in dryland soils. Linking farm management practices and crop productivity with microbial community structure dynamics is an initial step in establishing a knowledge base for farmers to exploit the soil microbiota to maintain healthy soil for crop production.

中文翻译：

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大平原北部豆类作物轮作系统中固氮菌群落结构和共生的驱动因素

摘要 美国和加拿大北部大平原的旱地和灌溉系统中豌豆、扁豆和鹰嘴豆等豆类作物的种植面积有所增加。由于与固氮菌的共生关系，将豆类作物轮作谷类作物生产系统可以减少对氮肥的需求。豆科植物-固氮菌​​的关系得到了很好的研究，但对豆科植物-谷物轮作系统中大块土壤中的自由生活细菌知之甚少。在这里，我们确定了整个蒙大拿州豆类-谷物轮作中整体 (16S) 和固氮 (nifH) 土壤微生物群落的群落结构。许多变量影响了微生物群落结构，但其中，灌溉导致社区组成和共生网络拓扑结构发生重大变化。有趣的是，与灌溉土壤相比，旱地土壤中的固氮群落更强大，包含更多的通才。共生网络支持识别不同的固氮关键类群，例如灌溉中的厚壁菌门和旱地土壤中的变形菌门。将农场管理实践和作物生产力与微生物群落结构动态联系起来，是为农民建立知识库以利用土壤微生物群保持健康土壤以促进作物生产的第一步。共生网络支持识别不同的固氮关键类群，例如灌溉中的厚壁菌门和旱地土壤中的变形菌门。将农场管理实践和作物生产力与微生物群落结构动态联系起来，是为农民建立知识库以利用土壤微生物群保持健康土壤以促进作物生产的第一步。共生网络支持识别不同的固氮关键类群，例如灌溉中的厚壁菌门和旱地土壤中的变形菌门。将农场管理实践和作物生产力与微生物群落结构动态联系起来，是为农民建立知识库以利用土壤微生物群保持健康土壤以促进作物生产的第一步。