Some people have driven by the many fields growing fresh vegetables in the Yuma Valley and wondered why there’s farming in the desert.
Or they see irrigation sprinklers watering empty fields for 24 hours a day and think it’s a waste of water.
But an ongoing irrigation and salinity project has recently found that the irrigation techniques used by local farmers exceed 90 percent efficiency. That means that hardly any water is being wasted in growing vegetables — even in the desert.
Researchers have also found that irrigation, rather than wasting water, pushes down soil salts that might inhibit the growth of plants. Watering fields also helps control salts buildup.
The University of Arizona Yuma Center of Excellence for Desert Agriculture, along with various private and public partners, is sponsoring a research project that is assessing the water and salt balance in the Lower Colorado River irrigation districts.
Dr. Charles Sanchez, professor of soil, water and environmental sciences at the UA, and other researchers under the umbrella of the UA and Yuma Ag Center, conducted the study in efficiency. The other researchers include Drs. Paul Brown and Dawit Zerihun of the U of A and Drs. Andrew French, Clinton Williams and Eduardo Bautista of the U.S. Arid Lands Research Center located in Maricopa.
“A lot of people’s perception is that farming in the desert is a waste of water, but it’s very efficient,” said Paul Brierley, director of the Yuma Ag Center.
A 2014 report by the Arizona Department of Water Resources established that irrigation systems in Yuma are efficient and getting better all the time. But it left many unanswered questions that members of the Yuma Water Agricultural Coalition, including water districts, wanted answered. They wanted to know more about the effect of salts on the multiple crops planted throughout the year. Some crops are very sensitive to salt, which pulls water away from plants. Some crops from starved from a lack of water due to salts.
The coalition members also wanted to know what is salinating the soil and if some crops push salts down into the soil.
The researchers found that using water to push down salts is a beneficial use, a legal term used to describe a good reason to allow the use of water.
This data could help farmers choose the best crop rotation to keep a water and salt balance.
“We’ve got to make sure we’re not setting up a time bomb,” Sanchez said, noting that some civilizations have failed because of salinization of soil. Farmers continually planted crops while salts continued to build up until crops stopped growing and led to starvation and the end of those civilizations.
Many Yuma growers are generational farmers and they would like to keep farming in their families for more generations, Brierley said.
As the project enters the second year, researchers are using high-tech tools that measure salinity and evapotranspiration, which is the process by which water is transferred to the atmosphere by evaporation from the soil and plants.
Some of the “space age” technologies being used include EM38 electromagnetic surveys, data loggers with sensors, Eddy-Covariance and large aperture scintillometer systems, drones and satellites.
“All of this exciting stuff is being done in Yuma,” Brierley said.
Ultimately, the researchers would like to use this “space age” technology, such as NASA sensors, and the collected data to develop an irrigation management phone app to help farmers make irrigation decisions. Irrigation doesn’t just water plants; it also helps manage diseases and fertilizer use.
“The whole point is to make everything more accurate. If farmers have more data, they can use it to make decisions, timely decisions,” Brierley said, pointing out that farmers are dealing with “high value crops here” and big investments.
“The goal is for them to be more productive, more efficient and more profitable,” he added.
The project has been funded through $388,000 in grants, but other contributions have brought the total funding close to $500,000.
“It’s a three-year project, but it may become a five-year project,” Sanchez said.
Brierley noted that all this equipment is based in Yuma so it allows the project to extend beyond the initial time frame.
In the 2017-18 season, researchers focused on produce crops and Sudan grass. Crop rotations studied in the future will include cotton, melons, spinach and even citrus.
The project is already considered a success. It has proven that farmers are being as efficient as they can with what they have now.
“They’re using less water and producing more,” Brierley said.
He expressed appreciation to local farmers for allowing researchers to set up equipment and collect data on their fields.
“We want to thank farmers for their cooperation. We couldn’t do it without them,” Brierley said.
“Sometimes we get in the way, but it’s a service to the greater cause. It may not be benefiting this crop right now, but it’s helping a whole industry,” Sanchez said.
For more information this project and other research projects, go to DesertAgSolutions.org.