The concept involves measuring water levels in the soil, the amount of water transpired from plants, evaporation losses, soil temperatures, and climate conditions. Time-domain reflectometry, which utilizes electrical signals sent through antennas placed in the soil, is used to measure soil water. Plant water use is monitored by electronic flow gauges placed around plant stems. Thermocouples are used to measure soil temperature and soil heat flux is measured with heat plates. A weather station records data on air temperature, humidity, winds, and rainfall.
Output includes an energy and water balance of the soil surface and plant cover.
Estimates of plant water use can be developed in a few hours. Last summer, the researchers field tested the concept on cotton crops grown on a 690' x 250' plot on the TAES farm at Lubbock. Lascano says that research results show that this new technology provided a more thorough picture of plant water use. Data from the studies will be valuable for researchers, and may be used to compare the water efficiency of different crops and to design efficient irrigation systems. This summer, the researchers will install a drip irrigation system that will water a cotton crop, based on field data and recommendations from the computer model.