Remote direct electrochemical sensing of water status is employed to yield a daily index of crop water status. The sensors are calibrated against a stem diameter measurement to yield a predictive, quantitative daily index. The index is transferred from the field to the grower's headquarters or pickup truck by telemetry. The system has low capital and labor intensity. It is amenable to most crop types. An exonomic analysis is developed for a 16,000 hectare system.
