Friday, April 21, 2023

Farmers wonder about sequestering carbon. It will take time to measure the soil's capacity, and the results may vary.

Photo via Successful Farming
It's no wonder farmers feel stress. They have to feed the planet, fuel cars, make sure their livestock is healthy, and now they have to decide whether to sequester carbon. "Much fanfare accompanies programs that pay farmers to sequester greenhouse gases such as carbon dioxide, methane, and nitrous oxide in their soils. Yet, questions linger as research casts doubt on whether the promise equals reality," reports Laurie Bedord of Successful Farming. Gregg Sanford, senior scientist, Department of Agronomy at the University of Wisconsin, told Bedord, "I worry that we are selling ourselves a pie-in-the-sky dream we might not realize, and that it could come back to bite farmers and ultimately not get us any further down the road toward reducing greenhouse gases in the atmosphere."

Bedord explains, "About two decades ago, Sanford began reading scientific literature that suggested certain farming systems could help combat climate change by sequestering carbon in the soil." Sanford told her, "We love to support farmers and incentivize them to do things that benefit society, but we also put a ridiculous amount of pressure on farmers to save us from every-thing. I don't feel the science is there to say that if you do these practices (e.g., cover crops, no-till, etc.), you will sequester carbon across the board. In some cases, we will, but in many cases, we won't." Bedord adds, "One of the caveats with soil carbon sequestration, Sanford says, is there are places in the United States where certain types of farming management will be able to build soil carbon resources, but results may vary."

"Sanford believes that to make a big impact on soil carbon and use it as a tactic to mitigate climate change, a transformational change must occur in agriculture," Bedord writes. "If the prairies built these soils, should we consider emulating what they can do in our production systems?" Sanford told her, "To get soils in the Midwest back as close as we can to those tallgrass prairies to stabilize or accrue carbon, we need to switch from farming systems dominated by annual crops to systems dominated by or exclusively built around perennials. . . . That is our best hope for building carbon in this region, but it's a big change and a hard pitch to make."

For now, soil, not carbon credits, is farmers' focus. "Initially, Kevin Bahr was among the carbon program skeptics. As he learned more about the Truterra carbon program, Bahr says it seemed like something worth exploring and joined the program in 2021," Bedord reports. "Like most central Kansas farms, Bahr's land is diversified. . . His soils range from good black dirt to sandy loam." Bahr told her, "While we may be talking about carbon, this program is more about soil health, which is a journey that doesn't happen overnight. . . I'm employing certain practices like no-till and cover crops because they are best for my soil; the carbon credit money is like gravy on top of my mashed potatoes. It's a reward for taking care of the land the way I should."

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