Water Irrigation Efficiency Program Spurs Innovation

When University of Arizona Cooperative Extension agreed to administer the state’s Water Irrigation Efficiency Program, which helps farmers and ranchers convert to more efficient irrigation, it wasn’t just about saving water.

It’s also about advancing science.

The $45 million state program will fund $3 million in University of Arizona research, which could help Arizona farmers stay financially sound as they face a future with an ever-shrinking water supply.

In its first year, the WIEP has approved more than 70 grants, with matching funds from applicants, to convert more than 18,000 acres in 11 counties from flood irrigation to more efficient drip or sprinkler irrigation. Combined, these conversions are projected to save more than 36,000 acre-feet of water annually – the amount of water used by more than 220,000 residents.

Funding Soil Science

Irrigation changes inevitably affect the composition and health of the soil, so in a demonstration project at Extension’s Maricopa Agricultural Center, soil health specialist Debankur Sanyal, Ph.D., and other scientists will study how crops like alfalfa, cotton, grains and produce fare with less water.

They’ll examine how lower water use affects the movement of salts (which can build up in soil and harm crops) at or below the root zone, how the soil retains and emits carbon, and even the physics of how water flows through it, Sanyal said.

“When you have water movement, when you have new irrigation methodologies, changes happen in the soil,” he said. “So, the big story is about irrigation methodology and irrigation rates, but the effects, the impacts on the soil health and carbon, that’s where I come in.”

Sanyal will study amendments, which are chemicals growers add to soil, and the movement of salts through Arizona soil under different types of irrigation, he said.

“If the growers adopt these technologies, what kind of challenges might they face in the future, from the soils point of view, from the plant nutrition point of view, from an environmental health point of view, and the salt, what happens to the salt?” he said.

Updated irrigation is unlikely to eliminate the need for flood irrigation completely. Farmers will still likely have to flood their fields annually to remove salts, Sanyal said.

“It is very likely, even if we move forward with modern sprinkler and gravity drip technologies, they will still have to do some kind of flushing out soils. With this research, we can help determine the frequency,” he said.

The ultimate goal is to keep Arizona farmers and ranchers thriving as our water supply dwindles.

“Most farmers are going to do something which is proven. We are staying one step ahead. We are going to try new things along with new technologies and see what happens. That’s why we have the agriculture experiment stations – to facilitate this kind of research,” he said.

Spurring Tech Innovation

Earlier this year, a grower applied to the WIEP for funding to get solid-set sprinkler pipelines on his farm.

“They wanted to get off of flood irrigation and get onto sprinkler irrigation, primarily for vegetables,” said Assistant Extension Agent Robert Masson, who works out of the Yuma Agricultural Center.

But solid-set irrigation pipe is used to irrigate winter crops, such as lettuce or spinach. It won’t work for summer crops like wheat or Sudan grass, which require flood irrigation through a series of ditches and gates.

“It’s very wasteful, because it over-soaks the ground near the gate, and it doesn’t get enough water to the other side of the field,” Masson said.

The WIEP requires applicants to submit an analysis showing the new irrigation systems will use 20 percent less water than their current systems. This grower was sure the sprinkler system would save water in winter, but summer flood irrigation would negate those savings.

The solution Masson, irrigation technician Hector Munoz and Videographer Donald Dinwiddie came up with is an adapter that converts a sprinkler head into a bubbler, allowing water to seep into the ground instead of spraying into the air. This allows a grower to essentially flood a field more uniformly with water coming out in a 30-foot grid instead of single gate, Masson said.

The team has secured a provisional patent on the sprinkler head to protect the idea until they can develop and test a prototype, which would then be patented, Masson said.

For the next step, the design team will work with Navajo County 4-H Fab Lab to develop a prototype. They’re planning a contest among 4-H members to design and 3-D print the bubbler, he said.

The bubblers could also allow precision salt management by allowing growers to effectively flood specific areas in fields instead of entire fields. The project is a good example of Extension fulfilling it’s mandate by responding to agriculture’s needs.

“This is us directly listening to them, and developing creative solutions,” Masson said.

Meeting Regional Needs

Although Extension and the WIEP are helping growers across the state, much of the work is happening in central and western Arizona, said Ethan Orr, Extension’s Associate Director for Agriculture and Natural Resources.

“Yuma and Pinal Counties are where most of the applications are and where most of that need is. Pinal because it took such a big ag water hit (when Central Arizona Project allotments were cut), and Yuma because all of that water is going back behind the dam,” Orr said.

All water used in Yuma comes directly from the Colorado River, meaning every drop saved is left in Lake Mead. In other areas of the state, water also comes from groundwater pumping or other surface sources.

“I think it’s been very successful. For a very small investment in money, we are saving a lot of water,” Orr said.

For more information about the Water Irrigation efficiency program, including how to apply for grants to convert irrigation, see our WIEP page.