A general form of Archie's model for estimating bulk soil electrical conductivity

Electrical conductivity can be used as a surrogate to study the spatial and temporal variabilities of a number of soil properties, e.g., porosity, salinity, clay content and soil moisture. In this study, we develop a general form of Archie's model that describes the relationship between soil electrical conductivity (sigma) and volumetric water content (theta). The input parameters include theta, sigma values at dry and saturated conditions (sigma(dry) and sigma(sat)), soil porosity (phi) and sand, silt and clay contents. A value of 2 was given to the water phase exponent (w) based on model calibration with sigma and theta datasets obtained from 15 soils. The general form of Archie's model was evaluated by comparing soil sigma estimates to measured sigma values from an additional 6 soils. The new model performed well by providing estimates with root mean square errors in the range of 0.008-0.399 dS m(-1) and relative errors ranging from 0.7% to 29.8%. The new model is simple, easy to use and ready for further evaluation on a wide range of soil conditions.

Automated summary

In this study, a general form of Archie's model was developed to describe the relationship between soil electrical conductivity and volumetric water content. The new model performed well by providing estimates with root mean square errors in the range of 0.008-0.399 dS m(-1) and relative errors ranging from 0.7% to 29.8%, showing its potential for further evaluation on a wide range of soil conditions.