• By Bob Johnson •
Now in its second year, a long-term project intends to learn whether rice farming in the Sacramento-San Joaquin Delta can succeed economically while helping to preserve the region’s uniquely carbon-rich peat soils.
Dawit Zeleke manages 350 acres of medium-grain rice on Staten Island in the delta for the Nature Conservancy, a worldwide environmental organization that has managed the 9,200-acre island for the past 20 years.
Located between the north and south forks of the Mokelumne River, Staten Island includes fields of corn, winter wheat, potatoes, pasture and alfalfa, with harvest schedules crafted to provide habitat for thousands of sandhill cranes that call the island home.
The shift toward rice represents an effort to preserve, along with wildlife, the delta’s heavily organic peat soils that are threatened by subsidence as water transfers and dry-soil crops cause the ground to emit carbon.
“By next spring, we’ll have 1,000 acres of rice on Staten Island,” Zeleke said as he looked over the crop in September. “We’re hoping rice takes off in the delta, because it’s a great crop for the birds and for the carbon and subsidence.”
Conservationists hope a combination of rice production and wetlands restoration will help save the carbon built up in delta soils.
“There are about 200,000 acres of subsided land with about 2 million tons of carbon emissions a year,” said Campbell Ingram, executive director of the Sacramento-San Joaquin Delta Conservancy, a state agency. “As subsidence continues, this will increase.”
The Delta Conservancy has developed a program to encourage farmers to keep carbon in the ground by flooding fields or planting rice.
“In many areas of the delta, water has been removed from the root zone in order to plant corn, because corn cannot be planted in wet soil,” according to the conservancy’s description of its carbon program. “Removing the water exposes the soil to oxygen, and microbes begin to eat the peat. This process reduces the peat and releases carbon dioxide.”
Rice acres continue to grow
Farmer interest in preserving the peat has already had a significant impact on cropping patterns: Rice was planted on a little more than 3,000 acres in the delta in 2017 but has steadily increased since and reached 5,000 acres this year.
“Acreage is going up a little because rice is supported by the Sacramento-San Joaquin Delta Conservancy,” said Michelle Leinfelder-Miles, University of California Cooperative Extension farm advisor in the delta region.
The cooler delta climate results in yields that may be slightly lower than in the Sacramento Valley but are still more than 8,000 pounds an acre.
“The waterfowl and sandhill cranes love it,” Zeleke said. “They’ll eat rice, corn or wheat.”
The Nature Conservancy has made sandhill crane habitat the highest priority in its management of Staten Island, which is home to about 15% of all the sandhill cranes in the state.
The organization’s early efforts at growing rice on Staten Island have produced yields typical for the delta, but Zeleke said it has not been easy.
“It’s a different crop, so we needed new equipment and new training for our people,” said Zeleke, who has farmed in cooperation with the Nature Conservancy for almost 28 years. “It’s a crop we’ve never grown before; it takes much more precise management of weeds and the depth of your flooding.”
Accounting for carbon credits
The Delta Conservancy encourages other farmers to grow rice by making it easier for them to document the carbon emissions they save and linking them with carbon markets that will pay them for their efforts.
“There is a California Wetland Protocol that allows you to calculate the avoided carbon emissions,” Ingram said.
The protocol, developed with technical assistance from Davis-based Hydrofocus, allows farmers to enter how much ground they keep wet for how long and to calculate the carbon emissions they are saving.
“We are just trying to help farmers connect with the carbon markets,” Ingram said. “We just completed our first third-party audit of a wetland project, and it netted about $62 an acre.”
The payoff could increase significantly, he said, if the conservancy can link its efforts to save the carbon-rich peat soils with the state’s broader greenhouse-gas program.
“We’re working to get the California Air Resources Board to adopt the protocol under the compliance market,” Ingram said. “Right now, we can get around $7 a ton for reducing carbon emissions, but with the compliance market, it would go up to $19 or $20. It’s just under a threefold increase.”
He said he expects rice farming in the delta to expand further, noting the delta has about 50,000 acres in “quasi-public ownership” between the Nature Conservancy and the Metropolitan Water District of Southern California.
One of the pioneers in using rice to keep carbon in the delta soils was the Stockton-based Cortopassi farming family, which deeded 750 acres of land west of Lodi to the Wetlands Preservation Foundation. Farmed in a wildlife- and soil-friendly combination of rice and wetland, this tract — known as the Black Hole — has become familiar habitat for sandhill cranes and other wildlife.
Zeleke said the Nature Conservancy’s preliminary results with delta rice have been encouraging enough to inspire hopes to greatly expand its rice acreage on Staten Island.
“In the next six to 10 years, we plan to increase it to 4,000 acres,” he said. “We’re seeing if it works out economically, and want to share what we find out with other growers.”
This article originally appeared in Ag Alert, the weekly newspaper of the California Farm Bureau Federation.