Wednesday, June 29, 2022

Opportunity in the air

Intermittent flooding leads to water savings and potential profit from greenhouse gas offset credit sales.

alternate wet dry
In AWD, or alternate wetting and drying, farmers allow the flood water to recede to a ‘muddy’
state before reflooding the field. The number of days of non-flooded soil between irrigations varies between one to more than five, depending on soil type, weather and rice growth stage. — Photo Courtesy Mississippi State University

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By Mark Isbell

2016 presents an opportunity for Mid-South rice farmers to reap additional profits from irrigation conservation practices beyond just water savings.

They will have a chance to participate in a program that allows for creating carbon dioxide (CO2) offsets through the practice of intermittent flooding in either precision-leveled or zero-grade fields.

Departing from the typical continuous-flood scenario and briefly stopping irrigation mid-season allows the field to dry just below the point of saturation one time before re-flooding and is adequate enough to create offsets.

When soil that contains organic matter is flooded, methane is created by the natural activity of anaerobic bacteria in soil. Allowing the flood to briefly lapse halts the production of methane, explains Dr. Joe Massey of the U.S. Department of Agriculture’s Agricultural Research Service.

Reducing this methane production on a rice field through intermittent flood, also known as alternate wetting and drying (AWD), translates to up to 1 ton per acre of CO2 offsets. As long as the activity is properly verified, that offset is marketable.

AWD has been practiced by some producers for more than a decade to save irrigation water, which can amount to as much as 30 percent over traditionally irrigated rice. But verification and marketing of the offsets created through this process is new to the industry.

Ryan Sullivan and his father, Mike, have been practicing AWD for the past few years on their central Mississippi County, Ark., operation.

“What drives us to want to do more of it is knowing that we have the ability to use so much less water and make the same yields,” Ryan says.

“Another added benefit we see to practicing AWD is the potential to enter this carbon offset market.”

An ongoing project, partially funded by a USDA Conservation Innovation Grant to the White River Irrigation District, is working to make access to the offset market easier for farmers by streamlining third-party
verification. Buyers of the offsets require verification, but putting together all of the pieces can be difficult and expensive. Progress is being made, and farmers should be able to reap some of the benefits this year.

“I think this is a very intriguing thing to get involved in with agriculture right now,”Ryan Sullivan says. “During these hard times in farming, any extra bit we can get can only be a positive.”

Early efforts

In addition to university research and farmer participation, early grants from the U.S, Department of Agriculture’s Natural Resources Conservation Service with matching funds from Entergy Corp. shareholder’s Environmental Initiatives Fund helped pave the way for the current project.

“Supporting the low-methane rice production project with Arkansas rice growers supports both Entergy’s agricultural customers and Entergy’s commitment to sustainability and has helped fund the country’s first verifiable and marketable, low-methane rice protocol,” says Chuck Barlow, vice president of environmental strategy and policy.

“NRCS has put a lot into this effort for long-term benefits. Entergy has done the same, and we could not have done anything near the work without them,” says Dennis Carman, director of the White River Irrigation District.

Mark Isbell is a farmer in central Arkansas. He can be found on Twtter at @mjisbell.

Q. What is a CO2 offset?
A: Carbon offsets are created voluntarily by changing practices to reduce

greenhouse gas emissions that would have otherwise been created.

Q. Who purchases offsets?
A: Companies that want to reduce their environmental footprint for the sake of stewardship or to meet regulations.

Q: What is a ton of CO2 worth?
A: About $12 per ton at current rates, but some of that money goes to the verification process. Many believe the price will go up substantially in coming years.

Q. How can I participate?
A. Contact Dennis Carman at the White River Irrigation District to learn more:

Further reading:

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