Growing awareness and concern for the environment, changes in government policy, the return of the United States to the Paris Agreement, and strong demand for carbon offsets all indicate an appetite for one. another type of agricultural crop – carbon.
“There has been growing discussion of how to create a way for farmers to earn credit for climate-friendly practices that they have implemented or will implement in their operations,” Joe said. Outlaw, Ph.D., co-director of the Agriculture and Food Policy Center at Texas A&M College of Agriculture and Life Sciences and economist at Texas A&M AgriLife Extension Service, Bryan-College Station. “One of these means is to use the cultivation of carbon which would allow the capture or sequestration of organic carbon in the soil, allowing the sale of carbon credits to companies so that they can offset their greenhouse gas emissions. . “
However, many questions about the efficiency of carbon farming and its value to the farmer remain unanswered. Will there be incentives to attract enough farmers to make this work? How difficult will it be to implement and monitor these carbon capture methods? Will some farmers benefit more than others? Will farmers be credited for the actions they have already taken to reduce greenhouse gas emissions?
The carbon cycle
Carbon is constantly circulating through planet Earth. Light energy from the sun works as a fuel for the carbon cycle – a natural process that moves carbon through our atmosphere, biosphere, pedosphere, lithosphere, and oceans.
“Human activity has created the need to extract huge amounts of deeply sequestered fossil carbon as fossil fuels,” said Katie Lewis, Ph.D. with Texas A&M AgriLife Research, a soil fertility scientist in the Department of Soil and Crop Sciences, Lubbock. “When burned, these dense forms of carbon release massive amounts of carbon dioxide. “
She said more carbon dioxide is now being released than plant life on Earth and the oceans can naturally reabsorb. This excess carbon dioxide forms a blanket in our atmosphere, trapping heat from the sun and causing changes in climate.
Globally, soils are estimated to contain about 10 times the amount of carbon in the atmosphere, far more than what is found in normal vegetation.
“Carbon cultivation is seen as a way to help restore balance in the carbon cycle,” Lewis said. “It also helps soils build resilience to drought and increase agricultural productivity in a natural way. “
What is carbon agriculture?
“The idea behind growing carbon is quite simple: to remove excess carbon from the atmosphere and store it in the soil, where it will aid plant growth,” Lewis said.
Carbon cultivation involves the implementation of agricultural practices that improve the rate at which carbon dioxide is removed from the atmosphere and converted to plant matter and soil organic matter. It works by applying agricultural methods such as direct seeding or conservation tillage for minimal soil disturbance, mulching, composting, livestock rotation and the use of cover crops as a means of sequestering carbon in the soil. ground.
“The loss of carbon from the soil is primarily due to the removal of carbon-containing plant material, usually during harvest,” Lewis said. “Changes in land management can increase or decrease soil carbon, creating a new balance. The variation of the climate can also modify this balance. Carbon cultivation can be considered successful when the net amount of soil carbon captured or sequestered exceeds the amount lost.
Lewis said that to accurately estimate soil carbon storage or stocks, soil samples must be collected at a depth that will determine bulk density and organic carbon using a dry combustion method.
“Bulk density is needed to convert the percentage of organic carbon to an actual amount of carbon in the soil, a stock,” she explained. “The depth of sample collection will depend on soil depth and crop history. Deeper depths are likely where there is greater storage potential.
Lewis said another method of estimating carbon storage is to use a modeling approach based on management practices implemented within a farm.
“The outputs of the model should then be verified using lab tests,” she said.
In total, the US Department of Agriculture’s Natural Resources Conservation Service has identified at least 32 on-farm conservation practices known to improve soil health and sequester carbon. These practices also offer other benefits in terms of water retention, hydrological function, biodiversity and resilience.
Bet on a carbon bank
“Recently there have been discussions about creating a ‘carbon bank’ at USDA that would buy and sell carbon credits to farmers,” Outlaw said. “The credits could then be sold to companies needing to offset their emissions. “
This concept, which has received support from a number of farming, agribusiness, forestry and environmental groups, also makes accommodations for early adopters who have led the way in carbon sequestration practices.
“There hasn’t been a national cap-and-trade effort here in the United States for over a decade, but currently there appears to be a growing demand for carbon offsets,” said Outlaw. “There are already a number of private credit markets or carbon payment programs being considered or developed. This seems to support the idea that carbon cultivation could potentially be a way for farmers to generate additional income. ”
He noted, however, that for the overall carbon-based agriculture framework to be successful, it should include sound policies, public-private partnerships, precise quantification methodologies and supporting funding to effectively implement direct and scientific solutions. .
“It will also need to be done at a scale where we can achieve measurable carbon capture that promotes regenerative agriculture focused on creating and maintaining healthy soils that absorb and store carbon,” he said.
Is carbon agriculture sustainable?
The jury is still out on whether carbon farming can be sustainable in the long term.
“There are many technical and regulatory hurdles to overcome, as well as the concerns of some environmentalists that even its widespread implementation will not significantly reduce greenhouse gas emissions or provide only a temporary solution,” Outlaw said.
He said there are also concerns that carbon cultivation will mainly benefit certain agricultural regions. In addition, many farmers may not be able to afford the cost of implementing environmentally beneficial measures without some form of financial assistance.
Some farmers may have received government payments from the NRCS Conservation Stewardship Program to cover the cost of implementing certain conservation measures. However, this funding is capped by the Farm Law and there is no long-term guarantee of continued payments.
“Right now there is really no way of knowing if carbon cultivation would be an effective way to tackle climate change, but there is no doubt that there are many ways to bring benefits. changes in land management that would improve soil health and benefit the environment, ”says Outlaw.
Will carbon farming work for me?
Studies of soil organic carbon sequestration show that the Corn Belt, with its good soil, mild climate and reliable rainfall, is one of the best prospects for viable carbon cultivation. In addition, areas of the southern United States with long growing seasons and sufficient rainfall, as well as those with substantial irrigation, provide viable opportunities for carbon cultivation.
“Growing carbon will likely be more of a challenge for farmers in hot, dry parts of the country,” Outlaw said. “This is why there appears to be support for a voluntary system that adapts to climatic differences while providing a range of options from which farmers and ranchers can choose to determine the best program for their lands.”
USDA has a web-based tool called COMET-Farm to help farmers interested in transitioning to carbon sequestration practices. The tool provides a rough carbon footprint from user-supplied data and allows farmers to study different land management scenarios to see which one is best for them. It also guides the user in describing farm and ranch management practices, including alternative future management scenarios. Once completed, a report is generated comparing the carbon changes and greenhouse gas emissions between current management practices and future scenarios.
“As an economist and person with many years in agriculture, my advice would be for producers to do their homework and weigh the pros, cons and costs of carbon farming against its economic and other benefits. potentials for their operations, then decide if it works for them.