ESTIMATING SOIL PROFILE DEPTH WITH APPARENT ELECTRICAL CONDUCTIVITY FOR A TEXAS VERTISOL

Abstract

This study aimed to develop a relationship between apparent electrical conductivity (ECa) and soil profile depthin a shrinking-swelling central Texas Vertisol. A strong relationship (R2 = 0.73) between ECa and soil profile depth to thecarbonate layer showed that soil profile depth could be estimated using ECa measurements in these soils. This relationshipbest predicted profile depth when soils were near field capacity and moisture-related electrical conductivity was high. A highcorrelation (R2 = 0.69) between two mapped ECa datasets gathered under comparatively wet and dry conditions, showedtemporal and spatial stability of ECa variation patterns. Using the relationship between ECa and soil profile depth along withmapped ECa data, ECa variation patterns could be related to spatial variation of soil profile depth within the field. Informationabout soil profile depth could be useful in crop management under rainfed conditions, especially as profile depth influencesthe water supplying capacity (WSC) of a soil. With a relationship between WSC and soil profile depth within a field, spatialvariation patterns of mapped ECa data could be used to divide a field into zones and management units of contrasting WSC.