Corn: The convergence of carbon, climate & soil health
By Alex Amonette
“Corn farmers not only have the ability, but an obligation to play a role in the world’s collaborative effort to address climate change.” Those are the words of Keith Alverson, a sixth-generation corn and soybean farmer from Chester, South Dakota. He operates the 2,700-acre K2 Farms with his wife. Keith continued, ““Scientific measurements document the world is getting warmer, and farmers have the opportunity to consider best management practices to improve their soil health, which in turn will benefit the soil and climate for future generations.”
Keith delivered that strong statement at COP21 in Paris a few years ago, which he attended in his capacity as a board member of the National Corn Growers Association (NCGA). Because of Keith’s expertise and advocacy, the CCL Agriculture Action Team invited him to be a guest speaker in their webinar series. He appeared on the March 12 session of the series to talk about corn, climate and soil health.
Farming practices that sequester carbon, create rich soils, and earn money
Keith explained how his farming practices are sequestering carbon in the soil and increasing profits. These practices are creating soil carbon in concentrations unseen since the days when his great, great grandfather first farmed the land in 1879, and include the following:
- Ridge tilling – For the past 30+ years, Keith’s farm uses ridge-till, providing the soil protection benefits of no till and the soil-warming benefit of tillage by having permanent raised seed beds where row cleaners can clear crop residues ahead of the planter. “We plant into last year’s corn stalks. The heavy residue cover protects soil from wind/water erosion and provides a good environment for soil microbes.” It requires less diesel and gives us the ability to more precisely place nutrients where the crop will use them compared to conventional tillage, he explains, “So less energy is required to grow that bushel of corn.”
- Precision agriculture technology – This includes GPS and Sonic Guidance, tools that do precise applications and the driving of equipment using ultrasound to measure distances down to the sub-inch accuracy. This also includes yield maps, variable rate planting/fertilizer, and individually controlled sprayer nozzles. “Adapting to new technology around the farm increased our ability to manage our fields at the same level gardeners manage their gardens and has helped us to build soil organic matter in our farm,” says Keith.
- Zone management – Soil sampling, testing, seeding, fertilizer application (only where needed)
- Individual nozzle sprayer control – “We are careful not to have overlaps. So, we reduce herbicide and pesticide application using this method.”
- Veris – These are machines that measure electrical conductivity and organic matter content. “Our Veris has allowed us to map fields to create management zones and document that the areas with bigger yields have made our soil more stable and productive,” says Keith.
- Ground truthing tests – Verifying the data against field checks.
As a result of these practices, “On an annual basis, the Alverson corn production enterprise sequesters enough atmospheric carbon dioxide in soil to offset all GHGs (greenhouse gas emissions) tied to the operation — along with the carbon dioxide emissions from 370 cars,” according to Keith’s farm website.
Ridge tilling works. Here’s how.
Keith explained that the ridge planting low till strategy has revived the soil health. This method, which his family has been practicing for more than 33 years, leaves tons of crop residue in the fields after harvest and increases the farm’s soil carbon and yields. The process works because earthworms take the crop residue down into soil and incorporate it. All their hard work could be undone by tilling. “When the prairies were plowed, the carbon stocks were lost,” Keith explains.
So by not tilling his fields, Keith can keep that carbon sequestered even deeper than the topsoil. “With an annual crop, the corn provides deep roots and become carbon stocks in the soil at depth. The potential for carbon to stay in place is greater because there is less oxygen to decompose organic material at depth.” He hired Applied Ecological Services to study the farm’s carbon levels. Due to the ridge tilling, the total soil carbon in the corn/soy acreage is almost as high as a native pasture. (See chart below for specifics.)
The goal is zero-carbon corn. It’s like balancing our checkbooks. Are we returning more to our soil than we are taking out? Is there enough carbon being added to soil each year from crop roots and are we storing enough to offset annual losses of soil carbon?
Keith says, “The more organic matter we can build, the more crops we can grow. We keep tons of crop residue in the soil, and more is better. This is what provides carbs and protein for soil critters like worms and microbes, builds soil organic carbon, protects our soil, and protects our waterways. If we take care of the soil, the soil will take care of us as a family and farm and the environment.”
The NCGA Climate Task Force
Keith is also on the NCGA Climate Task Force. They have discussions around climate and the changes taking place. He says, “We (farmers) have not always been as involved as we should have, but we are working to get up to speed and are interested in how best to engage in conversations.” At COP 21, Keith talked about collaborative partnerships and how it works to help drive change across agriculture in a positive way.
NCGA, also a member of the Climate Smart Ag Group, is actively working on corn’s life-cycle analysis, ethanol (carbon accounting through life cycling of ethanol), the renewable fuel standard and low carbon fuel standard.
CCL is grateful to Keith for sharing with us how he is sequestering carbon. Farmers are important voices in our nation’s economy and our efforts to pass Carbon Fee & Dividend legislation, and these exchanges are a vital part of the conversation we’ve been having with farmers and ranchers around the country.
Don’t forget to check out the Agriculture Action Team’s full webinar series, featuring experts from American Farmland Trust; the U.S. Senate Committee on Agriculture, Nutrition, and Forestry; the National Farmers’ Union; and more.