In November, U.S. Farmers & Ranchers in Action (USFRA) and the Council for Agricultural Science & Technology (CAST) released a full report titled “Potential for U.S. Agriculture to Be Greenhouse Gas Negative.”
Through multiple webinars, the lead scientists and writers spoke about the inspiration to start this project and the main takeaways for American farmers. Kevin Burkum, CEO of USFRA, introduced Dr. Chuck Rice, Dr. Marty Matlock and Dr. Jerry Hatfield as the three lead researchers that “contributed countless hours on this project.”
Matlock, formerly of the University of Arkansas Resiliency Center and professor of Ecological Engineering in the Biological & Agricultural Engineering Department at the University of Arkansas, said the project began in 2020 with 26 research scientists from around the nation. The group believed that “greenhouse gas emissions from agriculture in the United States could be negative” – they just needed to find the practices to support the change.
Rice, a distinguished professor of soil microbiology at Kansas State, explained that the research team looked at multiple aspects of agriculture across the whole supply chain and determined five major areas to focus on: soil carbon management; crop production and the yield gap; nitrogen fertilizer management; efficient energy use; and animal production and management.
Improving soil carbon management is a key component that “represents about 40% of the opportunity for U.S. agriculture to be greenhouse gas negative,” Rice said.
The group focused on strategies to encourage carbon sequestration, such as planting more deep-rooted plants that will “sequester carbon deeper in the soil and at a greater rate.”
Rice recognized the benefits of minimal tillage, as well as crop diversity rotations, cover crops, perennials and livestock.
The yield gap compares how much a crop is currently producing in comparison to how much it could produce under optimal conditions. In order to close this yield gap, farmers need to “do more on less land,” becoming more efficient. “By increasing, intensifying and diversifying our crop production, we are making more efficient use of the land area and closing the yield gap,” Rice said.
Nitrogen is needed to successfully grow crops, but the way it’s managed in current agricultural systems leaves room for improvement. Rice mentioned how agriculture emits 85% of the nitrous oxide emissions in the atmosphere, mostly due to poor nitrogen management practices.
When applying nitrogen to the fields, farmers should be precise and only apply where it will be beneficial. This will reduce inputs while increasing efficiency and profitability.
Agriculture requires a lot of energy to maintain a farm’s infrastructure, move equipment across fields and irrigate crops (when necessary). Considering that agriculture is energy intensive, adopting ways to use renewable energy is “a huge opportunity to make an impact,” Rice said. The most common renewable energy sources used on a farm are solar and wind, from which energy can be provided without inhibiting or restricting the use of fields for growing crops or grazing livestock.
Methane can also be captured and used as an energy source, helping to reduce the need for importing energy onto the farm.
Methane is a major greenhouse gas, and “about 50% of methane emissions come from animal production,” stated Rice. Most of this methane is produced by ruminants, specifically through gastroenteric release and manure. Although reducing this production is “probably a little more difficult,” these researchers have found areas where reduction is achievable within the next five to 10 years.
By increasing the efficiency and digestibility of animal feed, farmers can greatly reduce methane emissions while increasing animal production. It’s also recommended to improve your pasture quality by improving your grazing management practices and properly managing manure.
Reducing greenhouse gas emissions from the U.S. ag sector will require a whole-system approach. American ag cannot become greenhouse gas negative while only focusing on one factor.
The full report is available online, but the work is not done. More on-farm research needs to be conducted to see how these changes will impact producers’ fields and production.
Rice noted that currently, “U.S. agriculture represents 10% of our greenhouse gas emissions,” but if farmers were to adopt their suggested strategies, that contribution could drop to – or even fall below – 0%.
To access the full report, visit cast-science.org/publications.
by Kelsi Devolve
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