Conservation through Innovation: Dynamic Variable Rate Irrigation

Water is one of the most precious resources we have on the planet. It is vital to all aspects of human life, including agriculture. That’s why this cutting-edge technique, which increases irrigation water use efficiency by up to 40%, is a powerful tool for the future of conservation and production.

In many parts of the United States, tensions are rising related to water use and water rights. Even in the Southeast, where we have plentiful rainfall most years, we are still embroiled in a decades-long “water war.” 

Despite the conflicts, we all agree that conserving water is a positive goal. In agriculture, we have dedicated scientists and experts striving to research and develop new tools to make water use as efficient as possible. Farmers rely on this precious resource to optimize the yield and quality of their crops.

A team of research scientists, conservation agencies, and local farmers in Georgia are at the heart of cutting-edge research and technology designed to increase agricultural water use efficiency. The foundation built by this team over the last decade has led to valuable new technologies that have been adopted globally. 

One example of this technology is Variable Rate Irrigation (VRI). VRI was first developed in the early 2000’s by scientists  at the University of Georgia’s (UGA) College of Agricultural and Environmental Sciences. VRI is a tool of precision agriculture that optimizes water application. The center pivot irrigation system is retrofitted to control water application rates with GPS guidance by  individual sprinkler or groups of sprinklers, depending on the type of system. With VRI, the center pivot applies customized amounts of water across irrigation management zones to address variations in the field, such as soil types or non-cropped areas, helping farmers determine where to irrigate. This can be as simple as removing non-cropped areas in the field from irrigation, or as complex as having customized rates of water based on soil type, topography, and hydrology.  

VRI began as a research project at UGA. Later, VRI was successfully commercialized and now major center pivot manufacturers and agricultural companies offer VRI as an irrigation tool. Through a partnership with the Flint River Soil and Water Conservation District (SWCD) and funding from the USDA Natural Resources Conservation Service (NRCS), VRI was tested on local farms in southwest Georgia. After refining the technology, the partners then developed the necessary guidelines to develop a conservation standard for VRI. Now, VRI is available as a practice for farmers to apply for financial assistance through the NRCS Environmental Quality Incentives Program (EQIP).

Calvin Perry, Superintendent of the UGA Stripling Irrigation Research Park, was on the team of UGA engineers that first developed VRI technology. 

VRI has proven to be an effective management tool for enhancing irrigated agriculture while conserving water resources. VRI technology essentially converts a center pivot system into a precision water delivery system.
— Calvin Perry

The UGA-USDA-Flint River SWCD team continues to innovate.  Building on the success of VRI, the team developed and tested the UGA Smart Sensor Array in 2011, a high-density, low-cost soil moisture sensor network. Irrigation scheduling with soil moisture sensors helps determine when to irrigate and how much water to apply. Sensors provide a gauge of current field conditions to determine if there is adequate moisture for the crop. Irrigation scheduling can optimize plant growth, crop yield, crop quality, nutrient management, root zone health, and irrigation decisions.

More recently, the partner team has been working to integrate the tools described above into an automated, farmer-friendly system. Dynamic VRI is a highly innovative approach to irrigation water management. This method of irrigation combines the above elements - VRI and soil moisture sensors - into a holistic system that utilizes real-time field data to apply the needed amount of water at the right time in the right location for optimal crop growth and development. 

UGA researcher, Dr. George Vellidis, and his team of precision agriculture scientists tested dynamic VRI as a proof-of-concept project in 2015. In 2016, the Flint River SWCD received funding to evaluate the technology on three additional fields. The UGA team divides the fields into wide parallel strips, with alternating strips utilizing dynamic VRI and managed by UGA and the others managed according to the farmer’s irrigation scheduling method. 

Consistently, the dynamic VRI system has increased irrigation water use efficiency by up to 40% while increasing yields between 5 and 10%. Put simply, that means “more crop per drop” - on a large scale. The system has been tested on cotton, corn, and peanuts. 

Dynamic VRI is a tool that will allow us to improve the sustainability, efficiency, and profitability of our irrigated farming systems.
— Dr. George Vellidis

Though these results are very encouraging, there is still progress to be made. The Flint River SWCD is leading another project, funded by the NRCS Conservation Innovation Grant program, to build on this success and develop the technology necessary to have a “farmer-ready” dynamic VRI system. Currently, dynamic VRI requires coordination with an irrigation expert and the installation of expensive technologies. The new project, conducted in cooperation with UGA, Auburn University, and farmers in Georgia, Florida, and Alabama, will develop a comprehensive decision support tool and make dynamic VRI feasible for more growers to adopt. Irrigation companies are paying attention to this work and are already developing versions of this technology to be available commercially in the near future.

Farmers are stewards of the land. With today’s evolving technology, conservation is more cutting-edge and impactful than ever. Technologies like dynamic VRI hold great promise for the future of optimizing our water resources through conservation-driven innovation.  

Originally published in Growing America