Spatial and Temporal Variations of Soil Electrical Conductivity and Penetration Resistance

Research Findings, Reports, and Publications for this Project

Electrical conductivity (EC) is a measure of the ability of soil to conduct electrical current that is expressed in milliSiemens or deciSiemens per meter. Mapping EC across a field provides spatially integrated depictions of a variety of soil characteristics that are highly correlated to crop productivity. Soil properties that affect EC include: soil particle size distribution, soil organic matter, soil nutrient levels, soil compaction, soil drainage, CEC, soil water holding capacity, and soil salinity. Research is needed to be able to identify and separate these into the most critical factors that can be managed in each area within a field.

As a way to assess of soil variability, we are mapping soil EC in our research plots and cooperator’s fields using both a Veris 3000 profiler (point measurement of penetration resistance and EC) and a Veris 3100 (continuous strip measurements of EC with depth) under irrigated soil conditions. Differential GPS technologies are used to geo-reference all data points which are then used to develop maps with a GIS. These maps can be very helpful in explaining crop yield variability and used as tools for precision farming.

Our long term research goals are to determine spatial and temporal variations of EC and soil compaction; identify field soil variability by creating soil EC and compaction maps and relate them to crop yield variability, We also want to use these data to develop functional relationships between soil properties (e.g., texture, aggregate stability, organic matter, bulk density, infiltration rates, and soil water holding capacity, and water content) that can be used in modeling these complex systems.