|Evett, Steven - Steve|
|Van Bavel, C.h.m.|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 6/30/1995
Publication Date: N/A
Technical Abstract: A design that combines and integrates the measurement and calculation of the daily crop water use in real time was implemented and tested. The system consists of 5 components: measurement, simulation model (calculation), a feedback loop that verifies calculated values of crop water use, water delivery (irrigation), and central processing and control. .The measurement component includes weather, crop transpiration (T), soil water content and temperature, soil heat flux and net irradiance. Crop transpiration is measured with the stem heat balance (stem gauges) and soil water content is measured with TDR. Sensors used for these measurements are connected to data loggers linked to a common computer. The simulation model (ENWATBAL) calculates water evaporation from the soil and the crop, profiles of soil water content and temperature, and components of both the crop and soil surface energy balance. The system is automated and measures in real time T, and soil water and temperature profiles, allowing for a direct verification of calculated values obtained with the model. In 1994, the system was tested by measuring cotton water use under the semiarid conditions of Lubbock, TX and in 1995, drip irrigation was added, also controlled by a central processor.