The Vellidis Research Group has several ongoing projects whose objectives are to develop a wide variety of tools which will enable farmers to better utilize their water resources. The projects range from developing smartphone apps for scheduling irrigation to developing smart wireless soil moisture sensing systems. The projects are described below.
The UGA Smart Sensor Array for Scheduling Irrigation
The UGA Smart Sensor Array (UGA SSA) is a low-cost wireless soil moisture sensing system. Its low cost allows a user to install a dense network of nodes to accurately characterize soil moisture variability. This type of information is necessary to make good irrigation scheduling decisions – especially if a variable rate irrigation system is used. The UGA SSA consists of smart sensor nodes and a Gateway. A “smart sensor node” is defined as the combination of electronics and sensors installed at each location in the field. A UGA SSA node consists of a circuit board, a radio frequency (RF) transmitter, soil moisture sensors and temperature sensors. Each sensor node accommodates up to 3 Watermark® soil moisture sensors and 2 thermocouples for measuring temperature.
Funding for this project was provided by Cotton Inc., the Georgia Cotton Commission, and the Georgia Peanut Commission.
Smartphone Technology for Managing Urban and Agricultural Irrigation
This project is developing Smartphone irrigation scheduling apps for citrus, cotton, strawberry, and urban lawn to provide real-time and forecasting information that can then be used for more efficient irrigation and water conservation. All four apps use a crop coefficient-based model for scheduling irrigation. The model uses a check-book approach to estimate when available soil moisture has been depleted by adding precipitation and irrigation to available soil moisture and subtracting FAO-56 ET adjusted by the crop coefficient from it. The Vellidis Research Group is responsible for developing the cotton model. The cotton model was developed and tested during 2012.
Funding for this project was provided by the USDA National Institute of Food and Agriculture and Cotton Inc.
FIST – the Flint Irrigation Scheduling Tool
To quantify the potential of precision irrigation, we began a research and demonstration project whose goal is to develop a soil moisture sensor-based variable rate irrigation (VRI) control system. The control system consists of the University of Georgia Smart Sensor Array (UGA SSA) – a wireless soil moisture sensing system with a high density of sensor nodes, a VRI enabled center pivot irrigation system, and a web-based user interface. Because the project is being implemented in the Lower Flint River Basin of Georgia, we named our system FIST – the Flint Irrigation Scheduling Tool. FIST’s operational paradigm is that the field is divided into irrigation management zones. The UGA SSA monitors soil condition within the zones and provides hourly soil moisture measurements to the web-based user interface. At the interface, the soil moisture data are used by an irrigation scheduling model running in the background to develop irrigation scheduling recommendations by zone. The recommendations are then approved by the user (farmer) and downloaded to the VRI controller on the center pivot as a precision irrigation prescription. When the center pivot irrigation system is engaged by the farmer, the pivot applies the recommended rates.
This project is funded by the USDA Natural Resources Conservation Service Conservation Innovation Grant program and is a partnership between the Flint River Soil and Water Conservation District, the University of Georgia, the USDA-NRCS, USDA-ARS, IBM, and several participating farmers.