On-farm testing of soil moisture sensor-based dynamic variable rate irrigation

Variable rate irrigation (VRI) for center pivots requires prescription maps which are developed by dividing fields into irrigation management zones (IMZs) and assigning application rates. Prescription maps are usually static. They are developed once and do not respond to environmental variables and other factors that affect soil moisture condition and crop growth rates. VRI water use efficiency may be improved by using real-time (dynamic) data of crop water needs to drive the application rates. One approach for creating dynamic prescription maps is to use dense soil moisture sensors networks to estimate the amount of irrigation water needed to return each IMZ to an ideal soil moisture condition. This paper presents the results from two years of on-farm testing of a soil moisture sensor-based dynamic VRI system on peanut. Dynamic VRI produced the same yield or lower yield than the uniform irrigation but with irrigation water productivity (IWP) gains of up to 40%.