Combating the looming water crisis with irrigation research

As the global population grows and water becomes scarcer, researchers around the world are looking for viable ways to reduce water use.

Agriculture is a good place to start. Around 80% of our nation’s freshwater resources go toward irrigating crops. At the University of Georgia, professor George Vellidis is taking a critical look at agricultural production systems, seeking to identify irrigation methods that are more sustainable and more efficient.

In the state of Georgia, the agricultural landscape varies widely in both the crops that are grown and the soil conditions in which they grow. A crop’s yield potential has a direct correlation to certain field inputs, like the amount of fertilizers and water required, and soil quality influences how much of these inputs are needed, depending on weather, precipitation, and climate.

During his career, Vellidis has focused his work on creating tools that allow farmers to vary water use in different parts of their fields. For the state’s main field crops—corn, cotton and peanuts—most farmers use an irrigating machine called a center pivot. Developed more than 70 years ago, the device was engineered to apply the same amount of water everywhere. But since different soils have different irrigation needs, Vellidis and his team designed variable-rate irrigation, an add-on system for the center pivot that can modify the amount of water applied to particular parts of the field.

Once they developed the technology to vary irrigation, the team wanted to figure out how to divide agricultural fields into management zones. What initially felt like a straightforward task, however, proved more complicated.

“The picture is more dynamic than we anticipated,” says Vellidis. “In terms of topography, fields are uneven. So, in rainy years, the lower parts of the landscape are very wet while others are drier. In dry years, the lower parts are often the driest.”

To gain a better understanding of the land, he and his team developed online tools to analyze big data sets and identify patterns for irrigating at different rates.

They’re also developing soil moisture sensing systems that are installed in the soil at different depths to help determine how much water to apply in each zone. Local farmers have been testing an early prototype: The sensors collect information and send it to a cloud-based server, which converts the data points into irrigation recommendations. Farmers can view how much water each zone needs on their smartphone and download the data to the center pivot controller. With this system, the team has already demonstrated on-farm irrigation water use efficiency improvements of 30 to 40%.