Error Estimation of Electrical Resistivity Based Soil Water Content in a Vertisol.

Accurate monitoring of soil water content is critical for effective management of agricultural land. Measurements of soil water content are needed for irrigation timing, predicting crop yields, and modeling soil hydraulic properties. Direct measurements of soil water content are difficult and expensive to make and therefore indirect methods are often used. One such method, known as Electrical Resistivity Tomography (ERT) generates maps of apparent soil resistivity which can then be related to soil water content. However ERT images are influenced by more than just water content. The presence of voids and cracks in the soil and user defined inversion parameters can both influence the final image and generate error in the resulting water content measurements. Before ERT based soil water measurements can be used appropriately, knowledge of the source and magnitude of such errors must be gained.