Research Highlights

Research Highlights
Fine Tuning an Irrigation App for Southern Soybean Farmers

The image from left to right shows notifications received by the user about crop and soil water deficit status, front page of App with all fields scheduled for irrigation and a data page of one field. The bar on the left indicates current soil water depletion or deficit.

By Barb Baylor Anderson

Soybean profitability opportunities in the southern United States are available, but sandy soils and periodic droughts limit consistently high yields. With better irrigation scheduling strategies and appropriate irrigation scheduling tools, farmers could address and more widely adapt best timing practices and apply the right amount of irrigation needed during the growing season.

The Southern Soybean Research Program (SSRP) and many of the states that are part of that program, continue to fine tune ways for farmers to irrigate reliably and easily. That includes work from Vasileios Liakos and George Vellidis, University of Georgia researchers, who have developed the SmartIrrigation (SI) Soybean App with funding assistance from SSRP and the Georgia Agricultural Commodity Commission for Soybeans. The App is designed to provide the most accurate, site-specific, real-time information possible with minimal user input.

“Our results over the past several years indicate consistently that the SI Soybean App performs well and can be a reliable irrigation scheduling tool for farmers,” says Vellidis. “The SI Soybean App can be used to schedule irrigation as effectively as soil moisture sensors with significantly less financial investment and effort as there is no need to install or remove sensors.”

The App works by continuously estimating the amount of water available in the soil profile and advises irrigation when the plant-available soil water reaches predetermined thresholds. Default values are when 50 percent of the plant-available water is depleted before the reproductive stage and when 40 percent is depleted during the reproductive stage. 

“This give growers ample time to schedule irrigation without stressing the crop and ensures that the soil profile is not over irrigated,” he says. “In the App, plant-available soil water is a function of the soil’s plant-available water holding capacity and current rooting depth. As plant roots grow, the depth of the profile from which the plant can extract water also increases.”

Although the App pulls meteorological data from a variety of sources, to perform at the highest level requires accurate precipitation data. That means very local precipitation data from on-farm rain gages are necessary. Liakos says data can be provided with an automated rain gage installed in or near the field. The App also can pull the data directly from websites of rain gage manufacturers or precipitation data can be added manually.

Updates to the App also continue. “We are conducting field trials to evaluate how the App performs for different maturity groups. They are treated uniformly now,” he says. “If we see significant improvement, we will incorporate the maturity groups feature into the App. We also recently received funding to integrate the corn, cotton and a new peanut App with soybeans to make irrigation scheduling simpler. We plan to add more rain gage manufacturers, too.”

Vellidis says the App communicates with the user via notifications, so it does not have to be opened on a regular basis. First released in 2019, it operates on both Android and iOS platforms and is available at no cost. Links to download are found at

“This type of cutting edge research leaves me feeling confident that my checkoff dollars are well invested in projects that I don’t have time for or am not quite ready to implement on my farm,” says Wendy Yeager, Orrville, Alabama, soybean farmer and vice president for the Alabama Soybean & Corn Association. “Technology and innovation results have proven to be helpful and increase the profits for all soybean farmers across the United States.”

Published: Nov 23, 2020

The materials on SRIN were funded with checkoff dollars from United Soybean Board and the North Central Soybean Research Program. To find checkoff funded research related to this research highlight or to see other checkoff research projects, please visit the National Soybean Checkoff Research Database.