In the ongoing battle against climate change, President Joe Biden's administration is incentivizing farmers to adopt practices that store carbon in the soil. However, doubts loom large over the effectiveness of this approach, according to interviews with soil science experts and a review of U.S. Department of Agriculture (USDA) research.
The USDA's plan relies heavily on farm practices such as planting cover crops and reducing tilling, aiming to slash agriculture's 10% contribution to U.S. greenhouse gas emissions as part of the country's net-zero goal by 2050. These practices also hold potential for ethanol producers to secure tax credits for sustainable aviation fuel (SAF) under the Inflation Reduction Act (IRA).
Despite the optimism, some soil scientists and researchers remain skeptical about the long-term effectiveness of these techniques in permanently sequestering atmospheric carbon. While acknowledging the environmental benefits, including erosion prevention and biodiversity increase, they caution against solely relying on these practices for climate policy.
“Will it help with climate adaptation? Absolutely. Should it serve as an offset for more permanent and long-lived pollutants? Absolutely not,” said Daniel Rath, an agricultural soil carbon scientist at the Natural Resources Defense Council.
The USDA has already allocated significant financial assistance to farmers for adopting these practices. However, some experts argue for more aggressive strategies to combat climate change, suggesting that current efforts might not be enough.
Adoption of cover crops and no-till practices has been on the rise, with 11% of farms now planting cover crops and about 40% using minimal or no tilling, according to USDA data. However, the effectiveness of these practices varies depending on factors such as climate, soil type, and crop rotation.
While some experts believe that these practices can lead to a net increase in soil carbon over time, others warn that the benefits can be negated if farmers revert to traditional tilling methods. Only 21% of farmers report using no-till continuously, according to the 2022 farm census, with about a third alternating reduced tilling with conventional tilling.
As the Treasury Department finalizes details for the SAF tax credit, ethanol producers are expected to source corn from farmers using these conservation practices. However, the specifics of fertilizer application, another requirement for the tax credit, remain unclear.
The IRA's funding for farm climate programs, including cover crops and no-till, highlights the importance of these practices in the government's climate strategy. However, experts caution that a more comprehensive approach may be necessary to achieve meaningful carbon sequestration in the long term.
