Soil water status and water table modelling using EM surveys for precision irrigation scheduling

Electromagnetic (EM) surveys have been used to quantify soil variability with respect to soil water storage in an irrigated maize field. A fluctuating water table (WT) sub-irrigates the crop in some places, and a wireless sensor network monitors real-time WT height and soil moisture, with large differences in soil moisture measured at any one time in these uniformly textured sands. Results indicate that EM38 survey data plus rainfall can be used to predict soil moisture (R 2 adj = 0.87) and height of WT (R 2 adj = 0.71) at this site, using a SAGA Wetness Index extracted from the digital elevation data.