WEINER, Ark. (DTN) -- Explaining why he grows long-grain hybrid rice, Arkansas farmer Scott Matthews highlighted how his farm continues to adapt to sustainability demands over time.

"We've got all of these climate-smart programs, and I'm involved in them, I get paid for them and I do them to the T. But at the end of the day, bushels keep me in business."

He added, "If you come back in three years, I may tell you something totally different. We change. We have to be able to adapt and change with everything."

Matthews was among the Arkansas rice farmers this week highlighting ways they are reducing aquifer depletion, becoming more efficient with the heavy irrigation demands of rice, and lowering methane emissions.

They were part of the Conservation Technology Information Center's (CTIC) 17th annual Conservation in Action tour, which visited farms in northeastern Arkansas, focusing largely on irrigation technology for the state's rice production. This year's tour included two full-size buses and a caravan of pickups at every stop along the way.

IRRIGATION STRESSING AQUIFERS

Arkansas is the country's largest rice producer, growing just over half of the country's rice production, planting on average about 1.2 million rice acres per year. More than 80% of rice is furrow irrigated with flat, plastic tubing with holes in it. It takes on average somewhere between 30-36 inches of water per acre.

While rice requires significant irrigation, a large swath of Arkansas' rice production area also sits on top of groundwater areas considered "critical," meaning they are becoming depleted. That includes areas such as the western half of Poinsett County, the state's largest county for rice production.

A 2022 state report looking at groundwater noted farmers along the Mississippi River alluvial aquifer had cut groundwater irrigation from 7.6 million gallons in 2015 to 5.6 million gallons in 2020, but the "sustainable yield" out of the region was projected at roughly 3.4 million gallons annually.

"There's a big push right now to go to surface water," said Mike Hamilton, an irrigation education instructor with the University of Arkansas Extension, adding there are farms that are 100% surface irrigated. "Water doesn't leave the farm unless they want it to."

PRECISION IRRIGATION TOOLS

Matthews' family in Poinsett County, Arkansas -- about an hour northwest of Memphis, Tennessee -- has been growing rice for 100 years and relied heavily on the aquifer during that time. Matthews noted that farmers north of him started hearing about aquifer depletion nearly two decades ago, but it started inches closer.

The area is already naturally flat, but Matthews precision-leveled the rice fields and built small levees to separate the fields into multiple rice paddies. The focus is to get the most uniform flood of water -- 2.4 inches at a time -- across the fields. Along with that are flow meters, sensors and pumps with remote shutoffs.

"Everything you see in this field is a mathematical equation. The grading of the ground, the coordinates of the levees, the pipe planner, the flow meter," Matthews said. "Today, we'd have to find something new to have a tighter math equation that what we're using here."

With all of that in place, Matthews said his farm used 16-17 inches of irrigation water, or about half of the normal demand. "We are doing our part for conservation."

To store water and rely less on the aquifer, Matthews also built a 400-acre-foot reservoir on the farm, a roughly $750,000 investment that included funding from USDA's Natural Resources Conservation Service (NRCS).

"The whole purpose of that was to try to take some of the pressure off the aquifer and our aquifer pump," Matthews said. "How much we use it during the year will depend on how much rainfall we get in the summer."

SAVE WATER, REDUCE METHANE

At one time, farmers may have built a reservoir or pond just to fill in a low spot on the farm, but irrigation-water storage is now increasingly a priority as the aquifer has become depleted and wells have to pump from lower depths, said Michele Reba, a research hydrologist with the USDA Agricultural Research Service.

"The decision that farmers are making is, 'I have a field of soybeans and rice, and I'm from too deep and spending too much money on pumping. So, I'm going to take that field out of production, and I'm going to store water on it for irrigation, and I'm going to take advantage of that 50 inches of rain that I get throughout winter and spring and use it to offset my pumping from the groundwater,'" Reba said.

Producers are also changing how they irrigate their crops, not only to adjust water usage, but also to lower methane emissions from rice production. Rice production globally accounts for about 12% of methane emissions, a greenhouse gas that is 28 times more potent than carbon dioxide. Depending on management and soil type, farmers can reduce their emissions anywhere from 20% to 60%, Reba said.

Here is where the goals of reducing water usage pair up with corporate and Biden administration goals of reducing greenhouse gas emissions.

The declining aquifers, efficiency demands and a push to lower methane emissions have combined to create more ways to irrigate rice, said Joe Massey, a USDA ARS research agronomist. Producers can lower their water usage 30% to 60% in some cases without affecting yields. Climate-smart commodity funds and corporate sponsorships have helped support those efforts, he said.

"We have entered into a golden era of rice irrigation that we've never really seen before," Massey said.

QUALITY-OF-LIFE ISSUES

Technology also translates into quality-of-life benefits. With as many as 50,000 irrigation wells, only a few have automatic shutoff. Manual shutoff means farmers must check wells at all hours of the night. "People will say once they start irrigating rice, it's a lot like owning a dairy. Someone has to be checking all day, every day," Massey said.

A remote pump shutoff and timers might run about $1,000 per pump, to save water. "But the selling point will be the quality of life," Massey said.

TIME FOR TIMERS

Approached by companies such as Cargill, Kellogg's and General Mills, the Arkansas Chapter of the Nature Conservancy has been running a pilot program to help producers install 500 timers on 50,000 acres. The Nature Conservancy is now working to scale up that program to put timers on as many as one-fourth of the irrigated acres in the state over the next five years. That's going to cost between $25 million to $30 million to make happen.

Adopting irrigation techniques such as alternate wet and dry (AWD) on rice farms can lower water usage by 20% while reducing methane emissions from those fields by more than 60%.

"There's a lot of corporate interest, obviously, in greenhouse-gas reduction," said Jeff Fore, director of ag for the Nature Conservancy in Arkansas, adding that there are more incentives to help pay growers to reduce emissions.

AWD, though, does require timely dry-downs of the irrigation water. If the dry-down period correlates with a heavy rain, that will save on irrigation, but it won't really translate into lower methane emissions, Reba explained.

The lower pumping also reduces carbon dioxide emissions from the diesel or electric pumps operating less.

CARBON CREDITS

Ryan Sullivan, a fifth-generation farmer from Burdette, Arkansas, said his farm began working both with Reba and Massey as long as 15 years ago to measure methane emissions and focus on water efficiency. Using AWD, Sullivan said they saw significant methane reductions but also were not seeing yield losses. The farm does two dry-downs of irrigation water throughout the season.

"We were able maintain our yields, pump less water and let the dry-downs happen to reduce the methane gas," Sullivan said.

Working on research led to Sullivan's farm also partnering with groups like USA Rice and Ducks Unlimited on a USDA Regional Conservation Partnership Program to use the Field to Market Fieldprint Platform.

Sullivan also connected with AgriCapture to certify its practices and methane reductions. Last week, AgriCapture announced it had sold credits representing the equivalent of 37,000 tons of carbon dioxide emissions reduced, generating the "first large-scale issuance" of carbon credits from the rice industry.

"Essentially, what that money is paid for is methane reductions and the water reduction," Sullivan said. "We're having to keep irrigation records and all of that."

Leaders at CTIC announced next year's tour will look at conservation practices in South Dakota. The date has not been set yet.

-- CTIC: www.ctic.org

Chris Clayton can be reached at Chris.Clayton@dtn.com

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