Widescale adoption of more sustainable farming practices could allow the U.S. agriculture sector to sequester more carbon than it emits, a groundbreaking new study suggests.
The research, conducted by 26 leading agricultural research scientists, found that the farming industry has the potential to become greenhouse gas negative through steps such as improved soil management. Agriculture currently accounts for approximately 10% of total emissions in the U.S., according to the Environmental Protection Agency.
“We are convinced there is absolutely huge potential in the ag sector for decarbonization,” Dr. Hannah Birge, senior scientist of food and water with the Nature Conservancy, said of the report in a briefing.
The study, commissioned by U.S. Farmers & Ranchers in Action and peer reviewed by the National Academy of Sciences, identified current practices and emerging technologies with the most potential for reducing greenhouse gas emissions.
The biggest opportunity for farmers lies in improving nitrogen fertilizer management, which is also one of the simplest changes. Crops on average take up half of the nitrogen they get from fertilizers, with the rest released into the atmosphere as nitrous oxide — a gas that has a warming potential 300 times greater than that of carbon dioxide.
By more precisely applying nitrogen to fields, U.S. farms could address up to 50% of total agricultural emissions, the study said. These practices also have the added benefit of adding more efficiencies and reducing fertilizer costs.
Nitrogen fertilizer management alone, however, wouldn't be enough to push U.S. agriculture to negative greenhouse gas status, even if the practice was utilized on 75% of farmland. To realize the full potential of emission reductions, the study said farmers will need to implement a variety of practices that also address challenges from animal production, food waste and energy use.
“The key message in this report is that this requires a systems approach. It’s not just looking at soil carbons; it requires a synergy between all of these elements,” said Dr. Chuck Rice of Kansas State University, one of the report's lead authors. “Not all ideas fit everywhere, and that’s another key message, but there are multiple strategies to achieve a negative greenhouse agriculture."
Beyond nitrogen fertilizer management, soil carbon sequestration and animal feed management represent the second- and third-biggest opportunities to reduce emissions. But changes to on-farm energy use, grazing management and manure management could also bring positive impacts.
Taken together, aggressive adoption of these practices have the potential to reduce farming's carbon footprint to minus 4% of total greenhouse gas emissions in the U.S. New technologies and emerging management practices, such as biomass production and on-farm solar systems, could push agriculture's share to minus 6%.
One of the major challenges in moving toward more sustainable farming practices is the cost. While many practices can ultimately provide farms a return on their investment, the transition involves several years of lower yields, making it a tough proposition particularly for small farms.
Dr. Marty Matlock of the University of Arkansas, another of the report’s authors, said climate action won't occur unless it makes business sense for farmers. Part of that requires recognition from consumers that these products are beneficial and worth paying more.
“We need to start thinking about our food system as a global positive good, a human good, not as a commoditized resource, and manage it effectively," Matlock said. "Which means we need to pay for carbon sequestration and ecosystem services on the farm, in the field."
