UGA teaching farmers to save water by scheduling irrigation
Since 2017, the University of Georgia Agricultural Water Efficiency Team (UGA AgWET) has been working to help farmers adopt advanced irrigation scheduling tools that allow them to conserve water by scheduling their crop irrigation based on crop water needs. The team – made up of 16 UGA faculty with expertise in irrigation, water quality and quantity, social science and youth education – has been working together to execute this project.
The on-farm portion of this project has focused on training county Extension agents in smart irrigation strategies for the agents to teach farmers.
Phone apps & soil sensors set schedules
Smartphone irrigation apps and soil moisture sensors are the scheduling tools the team has been training farmers to use with center pivot irrigation systems. Agents are working with growers to utilize the tools to schedule irrigation in their fields and then compare results with the producer’s standard irrigation method.
When the project started in 2017, the team had participating farmers in Burke, Bulloch, Coffee, Jenkins and Jeff Davis counties (located in Extension’s Southeast District) and Colquitt, Decatur, Irwin, Miller, Sumter and Terrell counties (located in Extension’s Southwest District) using both tools.
The first was the SmartIrrigation Cotton App for Android and Apple smartphones developed by UGA Precision Ag Expert George Vellidis. The Cotton App (www.smartirrigationapps.org) uses an evapotranspiration-based model to estimate when irrigation is necessary and provides the user with an estimate of how much water should be applied. It doesn’t require any sensors, sends the user notifications when action is needed and is free. A disadvantage is it requires accurate daily precipitation data to perform optimally. Farmers near one of Georgia’s statewide weather network stations can link to the station in the app.
The second scheduling tool farmers were asked to use is the Trellis soil moisture sensing system (www.mytrellis.com). It consists of three probes and wireless telemetry allowing the data to be viewed online from any internet-capable device. The three probes, each with two soil moisture sensors placed at 6 and 14 inches deep, were installed in different soil or topographic areas of each field to demonstrate how infield variability impacts irrigation. This helps agents and farmers learn to make targeted irrigation scheduling decisions based on how different parts of a field retain water.
The advantage of the soil moisture sending system is that it directly measures soil moisture in the field, which provides farmers with more confidence than the evapotranspiration model the cotton app runs on. Disadvantages of the soil moisture system are its initial expense, recurring costs, the need to install after planting and remove before harvest, and that each sensor only measures soil moisture in a narrow radius around the probe.
Phase 2 of AgWET
In 2018, county agents continued working with farmers to use the Cotton App and Trellis soil moisture system. The project added a social science component of surveys, focus groups and interviews to discover the agents’ and farmers’ beliefs, opinions and behavioral changes related to perception and adoption of the scheduling tools before and after using.
Counties involved in the 2018 were: Appling, Burke, Bulloch, Jenkins, Jeff Davis and Ware counties (located in Extension’s Southeast District) and Colquitt, Irwin, Macon, Mitchell, Sumter, Terrell and Turner counties (located in Extension’s Southwest District).
This year, AgWET has entered Phase 3 of the project. In Southwest Georgia, UGA Extension is partnering with the Flint River Soil & Water Conservation District (FRSWCD) to fund the project for the next two years in the following counties: Colquitt, Crisp, Decatur, Dooly, Miller, Mitchell, Sumter, Terrell and Thomas.
FRSWCD received funding from the Southeast Aquatic Resources Partnership (SARP) and the National Fish & Wildlife foundation to carry out their side of the project for the next three years. Counties that will be funded for the next three years include: Calhoun, Decatur, Dooly, Early, Grady, Miller, Mitchell, Randolph, Seminole and Terrell. Calhoun, Early, Grady, Randolph and Seminole counties will use the Irrigator Pro irrigation scheduling app for peanuts instead of the Cotton App. The FRSWCD portion of the project also includes seven peanut fields in North Florida and Southeast Alabama located in the Apalachicola-Chattahoochee-Flint River Basin.
Irrigator Pro is an irrigation scheduling tool for peanuts, corn and cotton developed by the USDA National Peanut Research Lab. Irrigator Pro is designed to provide irrigation recommendations based on scientific data intended to conserve water while maintaining high yields.
The FRSWCD project in Calhoun, Early, Grady, Randolph and Seminole counties focused on peanut irrigation will only use one soil moisture probe per field instead of three. Each of the probes will be equipped with three sensors located at depths of 8, 16 & 24 inches. The soil moisture probe is equipped with a soil thermometer and a rain gauge.
The Irrigator Pro app collects soil moisture sensor data and temperature data wirelessly through the cloud from the Trellis probe. The data is then sent to the app, which will issue an irrigation recommendation based on the soil moisture readings and crop development stage.
This summer, county agents or crop consultants are also working with farmers in Dooly, Decatur, Miller, Mitchell and Terrell counties on using the Cotton App in their cotton fields and the Irrigator Pro app in their peanut fields.
Extension agents in Southeast Georgia continue to work with farmers in Appling, Bulloch, Burke, Irwin, Jeff Davis, Jenkins and Jefferson counties. Since there was no dedicated funding to look at specific crops, agents and farmers were free to choose the crops and scheduling tools they used. All of the agents opted to use the soil sensors and some decided to use them with Irrigator Pro. Some agents and farmers are using the scheduling tools with their corn and pecan crops.
While soil moisture systems can cost farmers about $1,500 to buy (includes sensor station, base station and a 6-month data subscription), the Irrigator Pro and SmartIrrigation Cotton Apps are free to download and use through the Apple Store or the Google Play Store. While the SmartIrrigation apps are for use on Apple and Android smartphones only, Irrigator Pro may be accessed via the Internet for use on personal computers.
Southwest District Extension Water Agent Cale Cloud and Dr. Wes Porter, members of the UGA AgWET project, contributed information to this article.