Researchers at the University of Georgia College of Agricultural and Environmental Sciences are aiming to help farmers make smarter decisions about their water use through advancements in irrigation techniques.
The project aims to combat the looming water crisis that plagues the South and Southwest.
“Everybody’s using the water, and the resources are getting depleted very quickly,” UGA CAES professor George Vellidis said.
Vellidis and a team of graduate students and researchers are seeking to increase agricultural sustainability and productivity through their research project.
The project aims to use fresh water resources more sustainably in order to optimize crop yield for Georgia’s largest commodities, such as peanuts and cotton.
“When you plant the seed, it has a certain yield potential,” Vellidis said. “You can use irrigation to make sure you capture as much of that yield potential as you can. That’s what this is all about: to maximize our efficiency, [to get] more crop per drop of irrigation water.”
Vellidis is a professor of crop and soil sciences at the UGA CAES Tifton Campus and has been working on this project for the past 20 years, he said.
“We foresaw that with increased competition from municipalities, industries and agriculture, we were going to have to find a way to use these resources in a more efficient way, so we began developing tools,” Vellidis said.
In Georgia, most farmers use ground water from an underground aquifer, essentially rock that stores and transports water in order to water their fields, Vellidis said.
“The level of the water in the aquifer is declining over time because we’re using more and more of it,” Vellidis said. “We want to be more efficient so that we can use less water to produce the same amount of crop.”
Vellidis and his team research Variable Rate Irrigation, an “add-on” system for the center pivot that allows the amount of water irrigated to certain sections of the field to be modified.
A center pivot is the most commonly used irrigation system on Georgia farms. It is a self-propelled system that rotates around a central point, releasing the same amount of water to sections of the field through a large pipe located at the outer end of the system.
“You can imagine that’s pretty complicated because if you’re the center point of the circle, you’re covering smaller areas, so your sprinklers need to put out less water there,” Vellidis said.
Vellidis’ development with VRI works by tailoring the amount of water dispersed to different sections of the field to align with the amount of water the section requires.
“The whole paradigm over the last 50 years is ‘how can we make these things uniform so every part of the field gets the same amount of water?’” Vellidis said. “But our research has shown that the soils in our fields are very variable and the crops are growing at different rates, so the amount of water you should be putting on different parts of the field is different.”
Vellidis works with a team of graduate students to collect data out in the fields.
“At any research university, the graduate students are the work force of the program,” Vellidis said. “They are the ones that are in the forefront of actually trying to test these hypotheses and theories.”
Vellidis said the team is now taking a more data-driven approach to the project and aiming to create technology that can relate all the data and use the information efficiently.
“We can collect terabytes of data now on all parts of the field, and what we’re trying to do is figure out how to compile this data into smart decisions,” Vellidis said.
Vellidis' research initially began studying VRI for center pivot systems and developed into an effort that includes the use of smart technology. The team mapped the fields ahead of time and identified how much water different parts of the field needed.
"This is called prescription for the fields, so you can imagine, taking the field and breaking it up into little grids. Then, we assign a prescription to each one of those grid cells based on how much water is needed there,” Vellidis said.
After the prescription is made, the VRI Sensor Pivot applies the different rates of watering to the fields.
“We’re trying to use the drones now to get more information [about the fields] to make better prescriptions,” Villidis said.
Graduate student Stefano Gobbo is in his second year of the master of science program in crop and soil sciences and sustainable agriculture through a dual degree program with UGA and his Italian university, University Padova.
Gobbo is responsible for irrigation scheduling, which is based on the aerial photographs of a rotating thermal camera.
The team attaches the cameras to the drones and flies them over the fields to observe the fields’ visible physical conditions. This helps the team understand which sections of the field need certain amounts of water and which sections of the field are dryer than others, Gobbo said.
“Temperature is a really good indicator of the water, so we use these thermal images as a way to schedule irrigation.”
First-year graduate research assistant Lorena Nunes Lacerda is majoring in crop and soil sciences and also works with Gobbo on capturing and analyzing the thermal images.
“Stefano’s experiment is more or less the first part of my research thesis,” Lacerda said. “Next year, we are going to start to take it to a commercial field because we want our results to actually be ready and available for farmers to use.”
Vellidis and his team also use a system of sensors they have developed that measures soil moisture. The sensors, called the UGA Smart Sensor Array Nodes, are placed at various depths of soil and collect the moisture data and send it back to the farmers through a cloud-based system.
“Our project is about providing [farmers] with whole series of tools that allows them to make better decisions about how they use their water,” Vellidis said.
Vellidis said the research is largely funded by farmer-based organizations.
“The farmers also recognized that this is something that needs to be addressed,” Vellidis said. “We’ve had tremendous support from farming organizations both at the state and local level.”