Arizona farmers may excel at irrigation efficiency, but can they do more while addressing challenges surrounding natural salt levels in the desert soil and Colorado River water?

The desert soil is naturally salty. So too is the Colorado River, to a degree.

Natural soil salinity and Colorado River water can create deadly levels of salt for produce and other crops, according to Robert Masson, an Extension advisor with the University of Arizona. This is why farmers are forced to use more water than the plants need. Flushing salts below the root zone is necessary.

“Our challenge to water conservation here is salinity buildup in the soil,” Masson said. “We can easily reduce the amount of water that we use to get it to every single drop is exactly what the crop needs, and no more. But the problem is that when you do that, salt builds up in the soil.”

He continued: “We’re already bringing in slightly salty water with every watering we’re putting down because the natural river contains about 1.1 deciSiemens of salt per meter.”

University studies suggest that 1.3 deciSiemens of salt per meter will affect lettuce yields.

Addressing water savings and soil salinity appears to be the most daunting challenge, according to Masson. Saving too much water and irrigating desert crops with only what the crop needs is a recipe for yield robbing salt buildup in the soil.

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Therein lies the challenge. Political pressure to reduce irrigation use from the Colorado River is growing as the river system’s storage hovers below 40% of capacity. Drought conditions in the West and overuse of the Colorado River have led to lake levels at Mead and Powell to significant declines.

Masson says Arizona agriculture uses about 78% of the state’s water to produce food and fiber. Masson cites the University of Arizona’s Water Resources Research Center, which says 97% of the water in Yuma County, Arizona is used by farming operations.

“If we can save one quarter of all ag water, something like this could be pretty impactful,” he said.

Patent pending idea

Masson is a general agricultural Extension agent in Yuma. His current irrigation project uses a patent pending bubbler to efficiently flood irrigate crops like wheat and Sudan grass. The system shows promise as it has revealed 80% water use reductions in early studies.

The idea is relatively simple. Instead of flood irrigating a leveled field by pushing a head of water from one end of the field to the other that oversaturates the top end of the field, irrigation pipes with what are being called “Martin Heads,” are being studied for their ability to evenly distribute irrigation water. The heads are named after the University of Arizona’s current director of Cooperative Extension, Ed Martin, whose work has dealt with irrigation water management.

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According to Masson, the irrigation devices attach to standard irrigation pipes and act as bubblers. Instead of rainbird and other irrigation heads, these bubblers keep water close to the ground. The heads have various size holes in them to aid in even distribution of water between the top end of the field and the bottom end of the field.

It sounds simple, but challenges remain. The heads need to be mass-produced. That could be the easiest hurdle as Masson mass production could take place just across the border in Mexico as a fiscally inexpensive solution.

The solid irrigation pipe common to the Yuma region may not be the most efficient for such a system as it requires hand installation and removal. Automated or mechanical pipe removal may be more efficient. This will require a new system of irrigation pipe that Masson needs to test.

Other challenges include the cost to pump this water through irrigation sets. Masson questions how solar energy could effectively power irrigation pumps in a region that sees over 300 days of sunshine a year.

Masson remains optimistic given the history of public-private partnerships between the University of Arizona and private industry.

Speaking directly to the need transition the technology to a more efficient system of moving water, Masson said: “I would love to partner with anybody on this. I’ll just put this out there in the open: I don’t think we can patent this technology, but we should be making solar pumps. Instead of diesel powered pumps, we should have solar pumps. If Elon Musk can make a solar powered truck, why can’t we do this?”