Soils are notoriously spatially heterogeneous and many soil properties are temporally variable. Spatial variability of soil properties has a profound influence on agricultural and environmental processes, such as plant–water–soil interactions, water flow, and solute transport, resulting in within‐field plant yield variation and degradation of soil quality, to mention only a few. Field‐scale mapping of spatial variability and monitoring of temporally dynamic soil properties is necessary for a variety of edaphic activities, such as soil surveys, reclamation, crop selection, sitespecific management, and soil quality assessment. There are various approaches for characterizing soil spatial variability, but none of these has been as extensively investigated and is as reliable and cost effective as apparent soil electrical conductivity (EC_a) directed soil sampling. Geospatial measurements of EC_a are well suited for characterizing the spatial distribution of soil properties because they are reliable, quick, and easy to take with GPS‐based mobilized EC_a measurement equipment. Directed soil sampling based on geo‐referenced measurements of EC_a is a proven and robust means of characterizing the spatial variability of any soil property that influences EC_a, including sol salinity, water content, texture, bulk density, organic matter, and cation exchange capacity. It is the goal of this methodology paper to provide an overview of the characterization of soil spatial variability across multiple scales using EC_a–directed soil sampling with a focus on the field scale. Mobile EC_a equipment, protocols, guidelines, special considerations, data reliability tests, and strengths and limitations are presented for characterizing spatial and temporal variation in soil properties using EC_a–directed soil sampling.

中文翻译：

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田间表观土壤电导率

众所周知，土壤在空间上是异质的，许多土壤的性质在时间上是可变的。土壤特性的空间变异性对农业和环境过程（如植物-水-土壤相互作用，水流和溶质运移）产生深远影响，导致田间植物产量变化和土壤质量下降，仅举几例。对于各种土壤活动，例如土壤调查，开垦，农作物选择，特定地点管理和土壤质量评估，必须进行空间尺度的田间规模制图和对时间动态土壤特性的监测。表征土壤空间变异性的方法多种多样，但没有一种方法能像表观土壤电导率（EC）那样得到广泛研究，并且既可靠又具有成本效益。_a）指导土壤取样。EC _a的地理空间测量非常适合表征土壤特性的空间分布，因为它们可靠，快速且易于使用基于GPS的动员EC _a测量设备进行。基于对EC _a的地理参考测量进行的直接土壤采样是一种行之有效的方法，可用于表征影响EC _a的任何土壤特性的空间变异性，包括溶胶盐度，水分，质地，堆积密度，有机质和阳离子交换容量。该方法论论文的目标是使用EC _a概述多个尺度上土壤空间变异性的特征。–指导土壤采样，重点是田间规模。提出了移动EC _a设备，协议，指南，特殊考虑事项，数据可靠性测试以及强度和限制，以使用EC _a指导的土壤采样来表征土壤特性的时空变化。