Can farmers fight climate change? New U.S. law gives them billions to try
$25 billion to expand and safeguard forests and promote farming practices thought to be climate friendly.
Those include no-till agriculture and “cover crops,” plants cultivated simply to protect the soil. Researchers, environmental groups, and the farm industry agree that paying and training farmers to adopt those measures will improve soil health and water and air quality. “I think pretty much everyone across the board is pretty happy,” says Haley Leslie-Bole, a climate policy analyst with the World Resources Institute. But how much these practices will slow global warming is unclear.
“It’s probably going to be positive, but how positive we don’t really know yet,” says Jonathan Sanderman, a soil scientist at the Woodwell Climate Research Center. A major factor is whether the U.S. Department of Agriculture (USDA) spends the money on the practices most likely to have climate benefits. Another challenge is measuring and quantifying the reductions, a task complicated by the great diversity of U.S. land and farming practices and the complex biogeochemistry of the carbon cycle.
The new bill expands funding for those programs, allowing more farmers to get a per-acre payment for a wide range of activities expected to reduce or sequester carbon emissions, including no-till and cover crops.
Those interactions vary enormously with soil type and environmental conditions, and it can take years for the impact of changes in crop types or farming techniques to emerge.
Another reputedly climate-friendly practice is no-till farming, which is growing in popularity. By not plowing fields, farmers protect the topsoil from erosion. They also save on diesel, which benefits their bottom line and reduces carbon dioxide emissions. Crop yields can increase as carbon accumulates in the upper root zone, enriching the soil and helping it retain moisture.
Many climate advocates say the most cost-effective way to help the climate through agriculture is simply to farm less land and raise less livestock. That means persuading farmers not to convert grasslands or other carbon-rich lands to row crops such as corn and soybeans. But the bill includes no additional funding for USDA’s main program for protecting sensitive private land, the Conservation Reserve Program.
the bill also includes a special pot of $300 million for USDA and partners to collect field data on carbon sequestered and emissions reduced—data could help target future climate efforts more effectively, he and others say. “That’s really significant,” says Alison Eagle, an agricultural scientist with the Environmental Defense Fund. “This investment can help direct the next set of funding to the right place.”
The new money will expand on grants USDA recently funded, such as a 5-year project Ellen Herbert, an ecologist with Ducks Unlimited, is leading to measure carbon in wetlands across the central United States. She hopes to learn whether restoring wetlands or protecting adjacent land boosts the carbon they store. To resolve that, they’re taking unusually deep soil cores, delving to 1 meter or more. “It’s sometimes like trying to pound an aluminum tube through a brick,” Herbert says.
Also in the Midwest, agro-ecosystem scientist Bruno Basso of Michigan State University and colleagues are tracking how improved fertilizer strategies can lessen nitrous oxide emissions. In addition, they’re measuring soil carbon tucked away by perennial grasses planted on less productive parts of fields from North Dakota to Mississippi. Those grasses can be harvested for biofuels or hay—as well as cash for the carbon left by the roots—which perks up farmers’ ears, Basso says. “I say listen, you know what, there is a new crop and it’s called carbon.”
Data from the three projects will improve biogeochemical models that estimate daily fluxes of key greenhouse gases from agricultural land. One such model is DayCent, used by the Environmental Protection Agency and others for the national greenhouse gas inventory. “The accounting is not glamorous,” Himes says, “but if you don’t get that right, nothing else works.”
