Long-term, systems-based experiments have previously demonstrated how different cropping systems change soil physiochemical properties and, less commonly, soil microbial communities. These long-term experiments allow for isolating the effects of management on soil microbial communities by minimizing variability in soil type, climate, and short-term effects of management intra-annual variability, and thus are able to inform best practices for regional cropping systems. In this study we address whether soil microbial communities are uniquely affected by upper Midwest US cropping systems’ management in a 26-year-old trial and examined how well microbial community responses to management track observed changes in soil physiochemical properties. We found that microbial biomass was highest in continuous pasture, lowest in continuous corn, and intermediate in alfalfa-based dairy forage rotations for both fungi and bacteria. Fungal taxonomic richness exhibited the same trend, but bacterial richness did not differ among cropping systems. Microbial community composition differed significantly among the cropping systems but could not be further explained by physical or chemical differences linked to particular management practices. We conclude that upper Midwest U.S. cropping systems cultivate distinct soil microbial communities, justifying further research on proximate drivers that cause the observed patterns and the consequences of altered microbial communities.

长期的、基于系统的实验先前已经证明了不同的种植系统如何改变土壤理化特性，以及不太常见的土壤微生物群落。这些长期实验允许通过最大限度地减少土壤类型、气候的变异性和管理年内变异的短期影响来隔离管理对土壤微生物群落的影响，从而能够为区域种植系统的最佳实践提供信息。在这项研究中，我们在一项为期 26 年的试验中解决了土壤微生物群落是否受到美国中西部上部种植系统管理的独特影响，并检查了微生物群落对管理的反应如何跟踪观察到的土壤理化特性的变化。我们发现连续牧草的微生物生物量最高，连续玉米最低，以及用于真菌和细菌的以苜蓿为基础的乳品草料轮作的中间体。真菌分类丰富度表现出相同的趋势，但细菌丰富度在种植系统之间没有差异。不同种植系统的微生物群落组成存在显着差异，但无法通过与特定管理实践相关的物理或化学差异来进一步解释。我们得出结论，美国中西部上部的种植系统培养了不同的土壤微生物群落，证明了对导致观察到的模式和改变的微生物群落后果的直接驱动因素进行进一步研究是合理的。不同种植系统的微生物群落组成存在显着差异，但无法通过与特定管理实践相关的物理或化学差异来进一步解释。我们得出结论，美国中西部上部的种植系统培养了不同的土壤微生物群落，证明了对导致观察到的模式和改变的微生物群落后果的直接驱动因素进行进一步研究是合理的。不同种植系统的微生物群落组成存在显着差异，但无法通过与特定管理实践相关的物理或化学差异来进一步解释。我们得出结论，美国中西部上部的种植系统培养了不同的土壤微生物群落，证明了对导致观察到的模式和改变的微生物群落后果的直接驱动因素进行进一步研究是合理的。