Field‐scale apparent soil electrical conductivity

Abstract

AbstractSoils 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 (ECa) directed soil sampling. Geospatial measurements of ECa are well suited for characterizing the spatial distribution of soil properties because they are reliable, quick, and easy to take with GPS‐based mobilized ECa measurement equipment. Directed soil sampling based on geo‐referenced measurements of ECa is a proven and robust means of characterizing the spatial variability of any soil property that influences ECa, 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 ECa–directed soil sampling with a focus on the field scale. Mobile ECa equipment, protocols, guidelines, special considerations, data reliability tests, and strengths and limitations are presented for characterizing spatial and temporal variation in soil properties using ECa–directed soil sampling.