Correlation of electrical resistivity, electrical conductivity and soil parameters at a long‐term fertilization experiment

Abstract

Geophysical methods are progressive, non‐destructive but indirect techniques for characterization of soil properties and mapping of soil heterogeneities. Geophysical surveys for soil mapping lead generally to ambiguous results since geophysical parameters are influenced by several soil properties, e.g., organic content, clay content and bulk density.The investigations presented here focus on the effect of different stages of organic content on DC‐geoelectrics and electromagnetic induction (EMI) at a long‐term fertilization experiment. This experiment gives, after 105 years running, an excellent opportunity to study the correlations between electrical resistivity, apparent electrical conductivity and soil parameters. Results from DC‐geoelectrical measurements (profile length 80–160 m, electrode distance 0.5 m) twice, in August after harvest and in January during black fallow period, are presented. Additionally electromagnetical investigations were conducted in January.Correlations of resistivity and carbon input into the soil are significant and very strong; especially in January with but contradictive in summer and winter. The analysis of resistivity and apparent electrical conductivity is critical since bulk density and water storage capacity is influenced by fertilization and plant growth. Interpretation of a combination of DC‐geoelectrics and electromagnetical techniques on agricultural areas has to be done with respect to management aspects.