Understanding the spatial patterns of soil microbial communities and influencing factors is a prerequisite for soil health assessments and site-specific management to improve crop production. However, soil microbial community structure at the field scale is complicated by the interactions among topography and soil properties. The objectives of this study were to (1) characterize the spatial variability patterns of soil microbial communities at the field scale; (2) assess the influence of soil physico-chemical properties, topography and management on soil microbial biomass spatial variability. This study was conducted in a 194-ha commercially-managed field in Hale County, Texas, in 2017. A total of 212 composite soil samples were collected at 0–0.15 m depth and analyzed via the ester-linked fatty acid methyl ester (EL-FAME) method to characterize the microbial community structure and biomass. Soil electrical conductivity (EC), pH, soil texture, soil water content (SWC), soil organic carbon (SOC) and total nitrogen (TN) were determined for each soil sample. Topographic attributes, including elevation and slope, were derived from real-time kinematic (RTK) point elevation data. Interpolated microbial community maps at this scale revealed a spatially structured distribution of microbial biomass and diversity with patches of several hundred meters in different directions corresponding to the distribution of soil types and topography. Most of the microbial communities were autocorrelated at greater ranges within the same soil types than across different soils. The distribution of total soil microbial biomass was mainly affected by SOC and SWC. Soil pH and C:N ratio had a negative impact on the biomass of bacterial communities. Biomass of fungal communities was negatively influenced by slope and elevation. The results of this study have the potential to provide a basis for designing soil sampling plans in characterizing microbial community distribution and site-specific soil health management.

了解土壤微生物群落的空间格局和影响因素是土壤健康评估和特定地点管理以提高作物产量的先决条件。然而，田间土壤微生物群落结构因地形和土壤性质之间的相互作用而变得复杂。本研究的目的是 (1) 表征田间土壤微生物群落的空间变异模式；(2) 评估土壤理化性质、地形和管理对土壤微生物生物量空间变异性的影响。这项研究于 2017 年在德克萨斯州黑尔县的一个 194 公顷商业管理的土地上进行。在 0-0 时共收集了 212 个复合土壤样品。15 m 深，并通过酯连接脂肪酸甲酯 (EL-FAME) 方法进行分析，以表征微生物群落结构和生物量。测定每个土壤样品的土壤电导率 (EC)、pH、土壤质地、土壤含水量 (SWC)、土壤有机碳 (SOC) 和总氮 (TN)。地形属性，包括高程和坡度，来自实时运动学 (RTK) 点高程数据。在这个尺度上插入的微生物群落图揭示了微生物生物量和多样性的空间结构分布，在不同方向上有数百米的斑块，对应于土壤类型和地形的分布。与不同土壤相比，大多数微生物群落在相同土壤类型内在更大范围内自相关。土壤微生物总生物量的分布主要受SOC和SWC的影响。土壤 pH 值和 C:N 比对细菌群落的生物量有负面影响。真菌群落的生物量受到坡度和海拔的负面影响。本研究的结果有可能为设计土壤取样计划以表征微生物群落分布和特定地点的土壤健康管理提供基础。