Real-time soil water dynamics over large areas using multisensor capacitance probes and monitoring system

Better methods are needed to accurately measure and record soil water content in real-time and at specified depths on a held scale. Recent developments of such a system using multisensor capacitance probes offers great potential for rigorous investigation of soil water dynamics over large areas. The purpose of this report is to show some of the kinds of information that can be obtained using this system to study the real-time soil water content dynamics at short time intervals (10 min), typically at four depth positions, under long-term, held-scale conditions, with our probes located as far as 125 m form the data logger. The systems have been used in the field for three years of continuous study (at 10 min increments), to study changes in soil water content, at four soil depths (commonly at 10, 20, 30, and 50 cm) as part of a research project to quantify temporal and spatial variation in soil properties under plow-tillage (PT) and no-tillage (NT) maize (Zea mays, L.). The multisensor capacitance probes and monitoring system have proven to be highly sensitive and robust for field scale soil water research. Viewing the soil water dynamics in real-time provides opportunity for precise control over the timing and amount of water that needs to be applied for optimal crop production yet avoiding excess deep percolation losses of water and agrochemicals to groundwater. (C) 1998 Elsevier Science B.V. All rights reserved.