“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.

“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.

“The Native Americans came to their door frequently that winter, looking for sugar,” Ron says. “That family would make a bi-weekly trek to [nearby] Dell Rapids for supplies. But we stayed.“

From this vantage point, the Alversons have witnessed the turns of two centuries, two world wars, the Dust Bowl and Great Depression, the farm crisis of the 1980’s, boom times and droughts, and the arrival of scores of children with hopes and dreams of their own, all rooted in the start they got at the Alverson Home Place.

They also witnessed the depletion of soil carbon, a challenge that would set Ron on a lifelong mission.

By the time he graduated from Chester High School, Ron was ready to forge his own path by pursuing a degree in agronomy from South Dakota State University, a little to the north of the family farm. But he wasn’t sure if he wanted to follow in his father’s footsteps or become a veterinarian. With a little nudge from his brother Larry, Ron came back to the farm in 1974 and helped take over the operation from his parents, Eugene and Lois.

The Alversons raised corn, soybeans, small grain, hogs, poultry and beef and dairy cattle. Eventually they ramped down their livestock operation and concentrated on corn and soybeans, eventually innovating a low-till soil management system that helped rebuild soil carbon in their fields while planting three seasons of corn and one season of beans. It’s a story of leadership driven by one part curiosity and one part focus on the health and future of his farm.

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The future arrived in the early 1980s with the birth of Alverson’s son Keith. Ron didn’t know it at the time, but he’d brought along the sixth generation of his family to stay on the farm.

“That’s what dad did,” Keith says. “You grow up and get to have role models you get to go to work with every day. I guess I just wanted to be like Dad.”

Keith claims it was always his intent to be back on the farm to follow in his father’s footsteps. But at least one way he’s emulated Ron is through industry leadership. Ron helped found the South Dakota Corn Growers Association in 1987 and Dakota Ethanol in 1999, a biorefinery near the family farm. He currently serves as president of the American Coalition for Ethanol. Keith is a board member of both the South Dakota Corn Growers and the National Corn Growers Association.

Carbon Harmony is a project the two of them share and focuses on innovating crop and soil management techniques to improve organic matter in their fields, increase yields, achieve sustainability in their operation and accomplish something unprecedented in agriculture: zero-carbon corn.

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Soil organic matter is the cornerstone of soil health, productivity and fertility. If you want to grow a crop, you need it for two essential functions: first, as a revolving “nutrient fund” that helps distribute minerals that sustain the entire biome of flora and fauna within the soil and keeps life above and below ground in balance; second, to improve the physical structure of soil, maintain healthy tilth and absorb and hold water.  More is better.

Essentially all the carbon in the soil comes from the atmosphere: plants draw in carbon dioxide from the air and convert it to complex carbohydrates both above and below ground. Higher concentrations of soil carbon make for healthier soil systems and, by extension, better crops.

Through the process of photosynthesis over the course of a growing season, the atmosphere literally feeds carbon to the soil.

When organic matter decomposes, it releases nutrients in a plant-available form. Because lifeforms within the soil —  the “biota” of the soil — break down carbon structures in crop residue and store or rebuild new carbon structures, soil biota plays the most important role in nutrient cycling processes and, thus, in the ability of a soil to provide the crop with sufficient nutrients to harvest a healthy product.

In order to sustain a balanced nutrient cycling, the rate of organic matter addition from crop residues, manure and other sources should equal the rate of losses from organic matter decomposition. In other words, carbon is the cornerstone of a much larger process that drives fertility and crop yields.

Soil carbon also servers a structural purpose. Numerous soil biota help binding soil particles into larger aggregates, with carbon as a central building block. Aggregation is important for good soil structure, aeration, water infiltration and resistance to erosion and crusting

Before most of this was well understood, 20^th Century farmers learned the hard way what happens when you loose soil carbon. Prior to the arrival of settlers, the native prairie soil had a positive carbon balance.  No carbon was exported from the land.  Buffalo grazed the prairies, but the carbon in the grass they consumed was returned to the soil in the form of manure and their carcasses. When settlers moved in and started growing crops to produce grain and meat for food for people in cities, carbon started to be exported from the land.  Compared to the prairie, annual carbon additions to the soil were significantly reduced.  But this was only half of the story.  In order to control weeds in their crops, farmers used extensive tillage, and this decomposed existing soil organic matter stocks, releasing carbon to the atmosphere. Tillage also exposed soil to wind and water erosion.  The most traumatic lesson came during the Dust Bowl of the 1930’s when wind erosion stripped organic matter directly off fields and wrecked soil fertility.  By the middle of the last century, many areas lost 50% of the prairie’s original soil organic matter stocks.

“We tilled like crazy,” Ron Alverson recalls of his earliest experiences managing the fields of his farm in eastern South Dakota. “We had to fight the weeds somehow — had to bury those weeds deep so the crop would get up and get ahead of the weeds. Tillage was weed control.”

That was standard operating procedure around most of the country until the mid 1970s. The consequences weren’t as obvious as a dust storm, but data revealed an alarming trend.

According to a study by Ohio State University’s Soil Science Department, US soil organic matter plummeted by half between 1907 and 1947, a direct correlation with low yields and the heavy use of conventional tillage. Total organic matter content stagnated for the next 25 years at approximately 53% of the carbon content of native prairie.

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Only by the early 1970’s, with the advent of chemical weed control that allowed low-tillage management, breakthroughs in plant breeding and rapid increases in crop yields — and after six decades of cratering organic matter — did soil carbon begin to rebound. Slowly.

In 1983, Alverson was 32 and the fifth generation to manage the family farm. It was his turn to confront the challenge of replenishing soil carbon.

“My Dad, Uncles and Grandads were great leaders on this,” he says. “It’s a responsibility they took seriously. Back then, soil conservation meant planting trees to prevent wind erosion.”

For the modern-day Alversons, the challenge was to manage weeds and grow bigger crops while simultaneously improving soil organic matter — not just preventing its loss.

That’s where the art and science of soil design was born. In the Alverson’s part of the country, one cornerstone is a low-till management strategy known as “ridge-plant:” crops are planted in raised ridges that are left undisturbed. Corn residue is left between the ridges where earthworms, bacteria and fungi dine on the carbs and protein in the residue. Soil scientists call this soil organic matter formation process “humification”.

“Earthworms grab last year’s crop residue from the soil surface and drag it down into the soil and consume it along with other soil microbes,” explains Ron’s son Keith. “Minimum till allows the soil to build up natural structures through earthworm and old root channels and you’re not releasing as much CO2. You don’t have that intensive soil mixing tillage pass or multiple tillage passes. “

The ridges rise above the stover and absorb the warmth of the sun in order to accelerate the seed growth in the cool, early weeks of each new growing season.

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Aside from planting and the gentle dislodging of the previous year’s stalks each spring, the ridges on the Alversons’ fields haven’t been disturbed since M.A.S.H. aired its final episode.

“We farmers have made lots of progress,” Ron says. “When I was a young man, everybody plowed. Full inversion plow.  And then more tillage trips to prepare the seedbed and control weeds later.  But now you go through the countryside, you don’t see nearly as much tillage.  Soil scientists say average tillage intensity has been reduced by 50% since 1970.”

With thirty-three years of record-keeping on the soil organic content of his fields, the Alversons have been able show how corn crops and ridge-plant have driven the carbon content of his fields up across the board — in some cases to levels rivaling native pastures and prairies.

In other words, careful crop and soil design can lead to carbon harmony.

Thanks to evolutionary efficiencies in its cellular pathways, along with strides in breeding technology that have driven huge improvements in yield, corn can suck more carbon dioxide out of the atmosphere than most plants — and certainly more than any mechanical or chemical technology humans have ever attempted.

“It puts [CO2] into a form we can grab,” explains Ron Alverson. “It’s just so efficient at converting that carbon from the atmosphere in to carbohydrates, or the sugars that make up the entire plant structure.”

High production of plant biomass (roots and stover) means a lot of atmospheric carbon is added to the land.  For Ron and Keith Alverson of K2 Farms, that’s meant dramatic increases in the soil carbon of their field. In other words, when managed properly, corn crops change carbon from the atmosphere to carbon in the soil.

The key is photosynthesis — and corn is incredibly efficient at it.

Most people know that plants use sunlight, atmospheric carbon dioxide, and water to build carbohydrates during the photosynthesis reaction. Fewer realize that corn is among a relatively rare subset of plants — approximately three percent —that botanists refer to as “C4” plants. The term refers to the chemical pathway the carbon atoms take as they move through the plant. C4s are able to turn sunlight, CO2 and water into carbohydrates almost twice as efficiently as C3 plants, such as soybean, wheat or rice.

Satellite imagery techniques developed by NASA scientists can actually measure the magnitude and intensity of photosynthesis by plant material on the earth’s surface. This satellite imagery indicates that during peak growth periods of corn, the magnitude of photosynthesis is far greater than anywhere on earth, exceeding even the Amazon rain forests by 40 percent.

Why is that important? Because photosynthesis may be one of our best hopes of remediating carbon dioxide from the atmosphere. C4 plants do it better than any other crop — and although they only represent three percent of flowering plant life, they’re responsible for 25 percent of all photosynthesis on land.

That makes corn the reigning champion of carbon capture. And it makes those hundreds and thousands of acres you drive by gigantic atmospheric scrubbers.

Of course to many, farm crops are just a normal part of the annual carbon cycle: plants take in CO2 as they grow, plants release it when they decompose or are consumed.

“What makes corn different is that we’ve figured out ways to grow vastly more of it on the same patch of land,” Keith Alverson explains. “We’ve been able to breed varieties with bigger leaves and bigger yields. And every one of those leaves is a photosynthesis machine.”

So we when you see big corn crops, what you’re really looking at is a carbon capture colossus. Expecting any other crop to perform like corn would be like putting in a pinch hitter for Babe Ruth.

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Image Credit: NASA’s Goddard Space Flight Center

Because the rate of photosynthesis drives crop productivity, no major crop exceeds C4 corn for efficient calorie production!

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Corn is only behind soybean for efficient protein production !

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Corn is the only grain crop that provides enough biomass carbon to build soil organic carbon stocks!

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K2 Farm’s goal is to use the least land, water and fertilizer to produce calories and protein, and also to build soil carbon stocks and improve soil health.  Planting any other crop than corn is like pinch hitting for Babe Ruth! 

If you want to grow crops, whether it’s corn, cotton or cabbage, you’ll need to put in a variety of resources and effort to produce a harvest. And if agriculture is the cornerstone of civilization, the trick is to produce many, many harvests.

Ideally, your next harvest is better than your last.

But what exactly does “better” mean? For the Carbon Harmony movement, it’s a novel, maybe heretical concept: Zero Carbon Corn. Some think this just might be the summit of agriculture in our time.

According to National Geographic, with the dawn of agriculture, “cities and civilizations grew, and because crops… could now be farmed to meet demand, the global population [rocketed] from some five million people 10,000 years ago to more than seven billion today.”

There’s at least one thing modern farmers share with their ancient forebears: with each new season they want more yield with less input.

That’s not easy. It takes a lot of careful, experimentation and study. The good news is that modern growers have the benefit of 10,000 seasons of both.  And of course science.

These days, corn famers know a lot about the resources that go into each crop. And there are costs — not just in investments, but in outcomes. Consumption of energy and other inputs required to plant, protect and harvest a crop results in emissions you’ve probably heard of: carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Collectively, those emissions are known as “greenhouse gasses,” or GHGs. They’re a uniquely modern challenge. The biggest is the carbon in the form of CO2.

Environmental scientists calculate the “carbon footprint” of modern production processes like farming, construction, shipping, manufacturing or power generation by accounting for the total inputs of all energy and resources that activity consumes — and their output in carbon emissions.

For farmers of every kind, GHGs have now entered their productivity equation: a carbon footprint is a new indication of performance in that pursuit of higher yields from lower inputs. To the extent farmers want to get more with less, this means reducing that footprint.

So where do you find the big inputs that affect the size of a grower’s carbon footprint? On the farm, they include diesel fuel and gasoline used by tractors, sprayers, and harvesting machinery during field activity; electricity, propane and natural gas used for farm shops and crop drying/handling; diesel fuel and gasoline used to transport harvested grain from farms to market, as well as to move fuel, fertilizers, pesticides, etc. to farms for use.

Then there’s the energy used to mine and manufacture fertilizers, pesticides and machinery prior to farm arrival.  The use of fertilizer nutrients to keep crops healthy results in significant soil GHG emissions such as carbon dioxide, nitrous oxide, and methane.

The U.S. Department of Energy and the U.S. EPA have teams of scientists that build and refine models to calculate total GHG emissions resulting from the “cradle-to-grave life cycle analysis” of the production of all manner of modern products, including crops. In the case of corn production, this is referred to as “field to market” life cycle analysis.  The most widely used and prestigious life cycle GHG accounting model is the Greenhouse gas and Regulated Emissions and Energy use in Transportation (GREET) model developed by the U.S. DOE Lab at Argonne, Illinois.  The GREET model is available to the public. Farmers can use the GREET model to calculate the carbon footprint of their operation.

Here is an example of the 2016 GREET model assessment of “Mid-West Average” corn production as estimated by Argonne National Energy Lab scientists:

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 This GREET model analysis demonstrates that GHG emissions from the use of nitrogen fertilizer is the dominant source of GHGs during corn production

So at first blush it looks like there’s a whole bevy of inputs that lead to GHG outputs. But that’s only half — and if you’re interested in the concept of Zero Carbon Corn, at most half and maybe even less than half — of the story. Here’s why.

For more than three decades Ron, his brother Larry, and now Keith have specifically managed their crops and soils to build soil organic matter.  When soil organic matter stocks are building, carbon dioxide is removed from the atmosphere.  If soil organic matter stocks build at a fast enough annual rate, it can offset some, all or even more than all of the carbon dioxide emissions that have been emitted during corn production.

“We’ve used several keys to achieve our carbon footprint goals,” explains Keith. “Strategies like precision fertilizer management to reduce losses and emissions, and ridge plant and continuous corn to build soil organic matter. It’s a big investment of time, money and focus. But it’s paid off for us and has improved out soil’s productivity and health.”

In the ridge plant system, Keith explains, crops are seeded into permanent seedbed “ridges” that are “high and dry” when normal spring weather is cool, moist and not friendly to early crop development.  This elevated seedbed makes it possible to grow high residue producing crops like corn continuously and economically and at high yields with minimal tillage.

High yields are a critical factor in achieving Zero Carbon Corn. That’s because “C4” plants like corn photosynthesize and assimilate an incredible amount of atmospheric carbon dioxide in plant material per unit of land — far more than other commonly grown crops in the Mid-West United States, such as wheat and soybean.  A portion of this new root and and above ground  unharvested plant material can become soil organic matter.

But how does this carbon in above ground unharvested plant material become soil organic carbon?  Doesn’t it just decompose and fly off into the air?   Soil is teeming with life….some critters big enough to see, like worms, and lots of critters that are too small to see, like bacteria and fungi.  These critters grab this plant material and pull it into the soil, and eat it to get their carbs and protein.  Large critters like night crawlers, can pull this material down deep into the soil.  Watch this:

Follow a ridge-till regimen like the Alversons’ and grow corn continuously on any given parcel of land, and you pull more carbon out of the air each year and deposit it in the soil in the form of plant material much more effectively than if you rotate other crops on and off that parcel. As the Alversons have observed in careful measurements of their fields, this strategy leads to a positive carbon balance of the soil system. More carbon in the ground. Less in the air.

Suddenly that carbon footprint starts to shrink. With the production of high amounts of biomass from a C4 plant like corn — and the integration of it into the soil each season — the GHGs that are emitted during the production of corn is now offset by carbon deposition into the ground through biomass. Now you’re looking at the prospect of balance and a crop you can call “Zero Carbon”.

And there are big secondary benefits of improved soil carbon. As soil organic matter stocks build, so does water and nutrient holding capacity. A positive feedback loop kicks in……higher soil organic matter means higher yields, means even higher soil organic matter, means even higher yields……..

When the Alversons started to use the Ridge Plant system in 1983, soil samples were taken from each field and tested for soil organic matter content.  On average the concentration of topsoil organic matter in those fields was about 3.3%.  Now after more than 3 decades, soil tests during the past few years indicate that the topsoil in those same fields now average 4.8% organic matter.

Here’s a summary of the results of long-term soil organic matter testing done in several fields:

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But Soil Scientists say the change in topsoil (0-6 in.) soil organic matter content is not conclusive proof that total soil profile organic matter/carbon content is increasing.  Topsoil is just the “tip of the iceberg” so to speak. Soil organic matter/carbon must be measured throughout the full rooting profile of the soil. “In 1984 we sampled and tested soil in one field down to 40 inches in depth”, says Ron, “and then sampled and tested the soil in the same location again in 2015”.  Here are the results:

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“The results from this field perked our curiosity. We wanted to find out more”.  So, in 2015 Keith contracted with a professional soil sampling firm to quantify the soil organic matter in the soil profile that is commonly impacted by crop roots, residue and tillage.  Applied Ecological Services used soil type maps and landscape topography to select 110 sampling sites in K2 Farm land tracts that have been under various land use management scenarios over the past 2-3 decades.  AES technicians extracted 0-40 inch, 2 inch diameter soil cores from these 110 locations and did a laboratory analysis for soil organic and inorganic carbon and soil bulk density.  The chart below compares the total organic carbon (adjusted for soil bulk density) in soil under various land management practices:

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AES found that the Alversons’ fields, using the “ridge plant” system and growing corn three out of four seasons on a given field, have been sequestering about 1.5 tons more atmospheric carbon dioxide in soil per acre each year for the past 32 years than fields that have been chisel tilled and grew corn rotated with soybeans.  And the carbon content of long-term ridge-plant fields has been almost fully restored to current native pasture levels.

Now contrast the carbon capture power of the these fields with the GHG emissions from energy the Alversons consumed and the resources they used to produce the corn crop.  When this soil carbon sequestration credit is coupled with precision energy and fertilizer use efficiency practices, the result is better than a zero-carbon crop of corn — it’s actually carbon negative.

Put another way: on an annual basis, the Alverson corn production enterprise sequesters enough atmospheric carbon dioxide in soil to offset all GHGs tied to the operation — along with the carbon dioxide emissions from 370 cars.

That realigns the age-old pursuit of higher yields with fewer inputs and costs — and sets a precedent that should help agriculture keep civilization going another 10,000 growing seasons.

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Carbon footprints are also sustainability report cards.  When energy and resources are used efficiently and soil carbon stocks are rising,  environmental impacts are minimized and crop/soil productivity and resiliency improves.