Potential for U.S. agriculture to be a net-negative greenhouse gas emitter
Livestock production needs to focus on increasing feed efficiency, developing nutrient efficient grazing systems and improving manure management.
By Ann HessThere’s “Potential for U.S. Agriculture to Be Greenhouse Gas Negative,” and it comes down to five major areas for carbon footprint reduction. According to a new comprehensive study, led by U.S. Farmers & Ranchers in Action (USFRA) and supported by the Foundation for Food & Agriculture Research, soil carbon management, nitrogen fertilizer management, animal production and management, crop yield gap, and efficient energy use will be key to getting U.S. agriculture to a net-negative greenhouse gas emitter. Published by the Council for Agricultural Science and Technology, the analysis suggests aggressive adoption of conservation practices in these areas can more than offset its carbon footprint while increasing farmer profitability and farm resiliency.
USFRA will also introduce this report during an official side event at this year’s U.N. Climate Change Conference (COP29) on Nov. 20 in Baku, Azerbaijan.
"U.S. agriculture is helping to solve some of the world's biggest challenges, including feeding a growing population and sustaining livelihoods, all while reducing our impact on the planet," said USFRA chair Michael Crinion, a farmer in South Dakota. “This report is further evidence of agriculture's enormous potential to do even more in the future.”
"This report represents a pivotal step toward transforming agriculture into a key player in combating climate change," said Chris Boomsma, chief executive officer of CAST. "By collaborating with USFRA, we aim to disseminate these vital findings and promote practices that can lead to a more sustainable and resilient agricultural system."
In 2020, USFRA established an independent scientific working group to explore the viability of U.S. agriculture as a GHG-negative emitter. This analysis builds on the 2019 National Academy of Sciences report titled “Science Breakthroughs to Advance Food & Agricultural Research by 2030.” The final report outlines actionable strategies for reducing emissions while enhancing carbon sequestration.
“Right now, U.S. agriculture represents 10% of our greenhouse gas emissions. We think with medium adoption, we can get almost to zero, one or 2%. And then again, high adoption, and we're not talking 100%, we're talking 75% adoption, then we can draw down and actually be 4% or 6% greenhouse gas negative,” says Chuck Rice, Kansas State University and one of the compilers of the report. “I think this is a huge opportunity for U.S. agriculture, and it's not just reducing greenhouse gases, but again, many of these practices help decrease input costs and increase profitability of our farm operations in the United States.”
As for animal production and management, Rice notes the focus needs to be on increasing feed efficiency, developing nutrient efficient grazing systems and improving manure management.
Authors Ermias Kebreab, University of California-Davis; Logan Thompson, Kansas State University; and Kim Stackhouse-Lawson, Jasmine Dillon and John Sheehan, all with Colorado State University; note that since beef is the leading contributor to GHG emissions, it is the most appropriate sector to focus on for moving the needle to GHG negative agriculture. However, pork and poultry GHG emission reduction strategies also need to be addressed.
While the authors note the methods behind soil carbon sequestration are not fully recognized, excessive stocking rates can negatively impact soil health, leading to increased erosion and unwanted forage species. Finally, these practices can affect the storage capacity and permeance of stored carbon. The researchers say practices critical to improving long-term soil carbon stock in rangelands and contributing to GHG negative beef systems are:
Avoiding conversion.
Reducing cultivated or degraded lands.
Practicing adaptive livestock management.
Although ruminants have been scrutinized for their impact on the environment, including carbon emissions, dairy production contributes only 1.14% of all emissions in the U.S. The main sources of emissions from dairy production are feed production, the animals themselves (enteric and manure methane emissions), and farm management. To reduce the carbon footprint, the authors suggest the industry invest in genetics and management practices to improve forage and grain production and nutritive value.
“Dairy and beef cattle can better use alfalfa by (1) improving alfalfa to contain less lignin and/or altering lignin composition for better fiber digestion and (2) breeding legumes to produce less tannin in leaves, which reduces enteric emissions; and (3) inserting genes into alfalfa to add polyphenol oxidase and o-quinones from red clover (McCaslin et al., 2015),” the authors write.
Under managed grazing systems, soil health can be improved and carbon sequestration can be increased. These systems have the potential to be a carbon sink, not a source of carbon emissions, the authors concluded.
As for pork production, the authors suggest the sector focuses on reducing and ultimately replacing fossil fuels with renewable energy sources (on-farm solar and wind energy) and incorporating solid manure management systems. Using byproduct feeds can also contribute to net negative emissions by reducing crop production emissions. Supplemental feed ingredients, such as synthetic amino acids and phytase, may also aid in reducing pork’s carbon footprint. However, the tradeoff is often increased manure emissions since manure solid content is more volatile, the authors note.
For poultry, progress in bird performance and feed efficiency must be balanced with meeting consumer animal welfare demands. This can be accomplished through continued research in genetics, welfare, nutrition, antibiotic alternatives and alternative production systems. “Continued benchmarking of genetic differences should help the industry balance calls for improved welfare and shifting production systems while reaching a GHG negative target,” the authors write.
Finally, the authors say there is potential to improve animal protein yield. “The greatest opportunity for animal agriculture for reducing GHG emissions lies in improving feed use efficiency through improved diet formulation and animal genetics, and reducing GHG produced in feed production. However, to meet GHG negative goals, diet formulation must include environmental costs, renewable fuel alternatives in barns and feed mills, and enhanced animal production efficiency while maintaining high animal welfare standards.”
