Ron Alverson uses a shovel to jab at a tangle of corn stover and cobs that carpets one of hundreds of furrows in the home quarter of his family farm. Just a few dozen yards away, a house stands watch over the empty field, a perspective shared by five generations of Alversons since this corner of eastern South Dakota was still prairie.
“This is it,” Alverson explains of the decaying residue. “Tons of crop residue, more is better. This is what provides carbs and protein for soil critters like worms and microbes, builds soil organic carbon, protects our soil, protects our waterways.”
Ivory-colored leaves dotted with red cobs run in long rivers between raised brown ridges of earth as far as the eye can see. The contrast between the plant refuse and military-like ranks of ridges almost seems like a mistake.
In fact, it’s a calculated practice known as “ridge planting,” a low-till strategy that has revivified the health of the soil handed down to the Alversons from the generations that worked it for more than a century before them.
“In the decades of the early part of the last century, crop yields were low, extensive tillage was needed to control weeds, and a lot of the residue was removed for livestock feed and bedding.” Alverson says. “The carbon balance of the soil went negative. It was all screwed up. It was impossible to maintain soil carbon.”
That all changed about the time Alverson’s son Keith was in preschool. Back in 1983, Ron built up ridges, planted his crops in them and eliminated almost all tillage. Period. At the same time, corn crop yields were rapidly rising, we were seeding more and more plants per acre and this meant a lot more crop residue on the fields. To this day, the channels between those ridges hold the corn cobs, leaves and stalks after every harvest. The ridges rise above the insulating residue in order to capture the heat of the sun in spring and give crops a good start to the growing season. They also have a generation’s worth of atmospheric carbon buried beneath.
Since Ron began experimenting with ridge-plant management, he's driven up soil carbon on the Home Quarter by 77 per cent - to a concentration close to native pastures
“Minimum till allows the soil to build up natural structures through root channels and earthworms and puts more and more carbon from the atmosphere back into the ground. Earthworms and soil microbes feed on the carbs and protein in the residue and move it into the soil,” Keith explains. “After years and years with out tilling, that carbon is building up in the soil and doing a lot of good things to the system here. Reducing tillage means less soil organic carbon is oxidized. You’re not releasing CO2 by tilling it up. Our soil carbon balance is positive”
Since Ron began experimenting with a ridge-plant strategy, he’s driven up soil carbon in some case almost by double. Here at the Home Quarter, he’s improved soil organic matter content by 77 percent — a concentration approaching that in native pastures in the area.
Now it’s late October. Harvest is in. A cold wind is up. The yellow-gray stubble of corn stalks juts twelve inches from the tops of the ridges like bristles in a brush. Ron, 65, is retired — at least on paper. Keith, 36, has taken over, the sixth generation of Alversons to farm here.
For the moment, the father-son team seems relaxed now that harvest is done. As the two of them survey their most recent deposit of stover into the bank of ancient prairie soil, they take stock of the significance of the ridge-plant system.
Basically, they built a time machine.
Carbon Harmony is the story of how they did it, how others can do it, and how a life-long obsession with soil organic matter proves the positive impact corn farmers can have with an alternative approach to soil and crop management.
The project took more than 33 years to develop and spans 2,700 acres of corn fields, tons of crop residue and season after season of assiduous record keeping. The prize? Soil carbon in concentrations unseen since the senior Alverson’s great, great, grandfather rolled into this corner of eastern South Dakota in a covered wagon with his family and two oxen in 1879.
Today, standing between ridges that he’s left undisturbed since Reagan was in office, Alverson can claim that the ridge-plant strategy really has taken his soil organic content back in time — at a moment when carbon is the keystone to the future of sustainability.
The implication is big for more than corn farmers like Ron and Keith, but for anyone out to improve soil health and productivity, accelerate renewable energy and put the brakes on water pollution, greenhouse gasses and climate change. Follow Ron and Keith in the new growing season as they turn their obsession with soil carbon into a much more radical pursuit: zero carbon corn.