Intercropping has gained attention for its potential to enhance soil health and increase crop yields in agroecosystems, in which soil microbial community play a key regulatory role. Bacteria is critical for a variety of soil biological processes, so promoting the understanding of soil microbiome within bacteria can improve the agricultural management practices. Here, the responses of soil bacterial community composition, functions, and assembly to long-term intercropping were assessed using 16S rRNA gene sequencing in the mountainous area of Southern Ningxia, spanning approximately 10 years until summer 2022. The experiment comprised three field treatments: maize monoculture (MM), intercropping of maize and potato (MP) and intercropping of maize and soybean (MS). The results showed that intercropping altered the relative abundance of major phyla and genera, and life-history strategies, mainly influenced by microbial biomass carbon and enzyme activities. The ratio of K- to r-strategy bacteria showed a trend of MP (0.77) > MM (0.76)> MS (0.56). Soil bacterial community structure of MP and MS was significantly different and similar to that of MM, respectively. Bugbase and PICRUSt2 analysis predicted the phenotype and metabolic pathways of soil bacterial community in maize fields, revealing that maize-legume intercropping increased the oxygen tolerance of soil bacteria. Moreover, intercropping enhanced the co-occurrence network complexity and the roles of homogeneous selection and drift, while bacterial community assembly was mainly driven by stochastic processes in MM (62.32 %), MP (60.68 %), and MS (59.17 %) soils. A variety of complex factors strongly governed bacterial community and assembly processes, such as soil nutrient elements and moisture. In brief, the study revealed the effect of intercropping on soil bacterial community, contributing to the further understanding of agricultural management practices.

中文翻译：

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半干旱区玉米田长期间作异作土壤细菌微生物组组成及结构


间作因其在农业生态系统中增强土壤健康和提高作物产量的潜力而受到关注，其中土壤微生物群落发挥着关键的调节作用。细菌对各种土壤生物过程至关重要，因此促进对细菌中土壤微生物组的理解可以改善农业管理实践。在这里，使用 16S rRNA 基因测序在宁夏南部山区评估了土壤细菌群落组成、功能和组装对长期间作的响应，时间跨度约为 10 年，直到 2022 年夏季。该试验包括三种田间处理：玉米单作 （MM）、玉米和马铃薯间作 （MP） 以及玉米和大豆间作 （MS）。结果表明，间作改变了主要门和属的相对丰度以及生活史策略，主要受微生物生物量碳和酶活性的影响。K--r-策略菌的比例呈 MP （0.77） > MM （0.76） > MS （0.56） 的趋势。MP 和 MS 的土壤细菌群落结构分别与 MM 显著不同且相似。Bugbase 和 PICRUSt2 分析预测了玉米田土壤细菌群落的表型和代谢途径，揭示了玉米-豆科植物间作提高了土壤细菌的耐氧性。此外，间作增强了共生网络的复杂性以及同质选择和漂移的作用，而细菌群落组装主要由 MM （62.32 %）、MP （60.68 %） 和 MS （59.17 %） 土壤的随机过程驱动。各种复杂因素强烈控制细菌群落和组装过程，例如土壤养分元素和水分。 简而言之，该研究揭示了间作对土壤细菌群落的影响，有助于进一步了解农业管理实践。