Dig In

A Model of Conservation Agriculture That Can Save Our Planet

At the dawn of 2015, a submerged volcano in the South Pacific (not far from Fiji) boiled above the ocean’s surface. The eruption that lasted just a few days in January gave birth to an island that stood nearly 400 feet above its novel coastline. The austere beauty of Earth’s newest landscape of gray volcanic rock was projected to be short-lived. With nothing to protect the soft volcanic rock and ash from relentless ocean waves and tropical rains, water would soon rectify this transgression of land, wiping the island off the map before it was indeed mapped. To be sure, NASA researchers proceeded to observe and collect data for erosion rates on what is still Earth’s most recently created land—the island Hunga Tonga-Hunga Ha’apai—which they assumed would be gone in a matter of months.

The geological event is a reminder that the world is not yet finished. New land does come into being from volcanism or when submerged bedrock is exposed by sea level drop or tectonic uplift. That blank slate will either wash away, or it will go on to accumulate the features of a proper landscape: a meadow, a forest, flora and fauna, a village with field crops, a civilization with megafarms. The difference between those pathways depends on the formation of soil.

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Soil starts with weathering, as bedrock is broken apart into boulders and rocks and grit by running water, abrasive winds, freeze/thaw cycles, and plant roots that infiltrate any crack. Successive generations of plants live and die, contributing their detritus to the deepening layer. Deposition of sand, clay, silt, brought in on wind and water, add to the native bedrock minerals. The matrix of organic and inorganic attracts living organisms—fungi, microbes, invertebrate animals—that take up residence and make busy feasting on the endless smorgasbord. Climate will put its signature on the evolving soil, lending it a distinctive profile, as particles and dissolved nutrients leach toward the water table over centuries of precipitation, settling in soil layers or “horizons” based on size and chemistry. Soil formation is slow but ongoing, forming the living skin of all terrestrial habitats. For every landscape, bedrock is foundational. But soil is generational, and everything we value in a landscape beyond the austere beauty of barren bedrock depends on it.

Which is why, coincidental to the birth of Hunga Tonga- Hunga Ha’apai, the United Nations Food and Agriculture Organization (FAO) designated 2015 as the International Year of Soils. (December 5 is Soil Day.) The UN’s rationale for the designation was described in the poetry of a 2013 draft resolution “noting that soils constitute the foundation for agricultural development, essential ecosystem functions and food security and hence are key to sustaining life on Earth.” This recognition was particularly pertinent given “the pressures of a growing population” that will need to be fed and that the problems are “of a global dimension.” Those problems originate from human activities, particularly agriculture, and can be reduced to two categories: soil loss and soil degradation.

Black Blizzards

Soil loss is most dramatically illustrated by a photograph of a lonely homestead backdropped by what looks to be a soft pillowy mountain. A confluence of many factors contributed to the Dust Bowl of the 1930s—a political, economic, technological, and social milieu that promoted a rapid conversion of arid short-grass prairie into cultivated grain acres. Ultimately, the blaming finger points at the pervasive culprit: poor soil management. Once the deep-rooted native vegetation was turned under, there was nothing to hold the soil in place when drought set in and the winds kicked up. Over nearly a decade, 150 million acres lost millions of tons of topsoil—an estimated 3 million tons in just one outstanding day in 1935—carried away as “black blizzards” that blotted out the skies of East Coast cities.

Poor soil management is still at work, although more often the losses are subtle and incremental, as gentle breezes remove topsoil in wisps and ordinary precipitation runs off bare fields in cloudy rivulets. It’s erosion by a thousand tablespoons happening every second of every day around the world. Combining that with our tendency to pave over and build on prime farmland can account for most of the soil lost. Soil degradation is a bit more complicated and includes salt accumulated during irrigation, chemical pollution, nutrient losses over successive years of crop removal, and especially the loss of organic matter and living soil organisms that together are fundamental to water retention and nutrient cycling. Soil degradation eventually results in land devoid of agricultural potential, land that is desertified.

One recent estimate puts the loss at a third of the world’s arable land with an ongoing 1% of the global land area degraded every year, mostly as a result of our endeavor to feed ourselves. The problem seems intractably large and unavoidable and depressing, but turning this Titanic around happens acre by acre, and farmer by farmer. You can find solutions to global catastrophe in practice not far from where you eat.

Two Farms

Jake Trethewey pulls out a T-shaped tool and drives the longer prong into the ground. A twist later and he extracts a soil core. It’s as dark as coffee grounds and has the feel of cookie dough with added sand. He tells me the soil of his Geauga County farm—Maplestar Farm—is the best in the state. It even has a name: Chili (pronounced cheye-leye) is a loam, a soil that has sand, silt, and clay. The sand allows water to drain rather than pool, while the silt and clay help retain moisture and dissolved nutrients within the soil. Chili is not the famously heavy soils of Geauga County. If plants dream, they dream of Maplestar Farm soil. So do other farmers.

Jake’s soil measures around 3% carbon content, hence the coffee color. “We probably picked up a half a percent in the 10 years we’ve been cover-cropping,” he says. The land has been in the Trethewey family since 1940, when it was a dairy farm. The cows grazed around managed pasture, which meant plants always covered the soil. In the early 1970s, Jake’s uncle switched to harvesting hay and grain. “My uncle did a real good job of crop rotation,” he says. “He always did two to three years of hay followed by corn followed by small grain followed by hay.”

Despite his uncle’s diligent crop rotation, he sold off organic matter—in the form of grain, hay, and straw—and didn’t do enough to replace what was removed over the years. In the soil, organic matter holds onto water and resists soil compaction. Organic matter is food for soil life, the critters that we collectively call “decomposers,” which free up nutrients for the next sprouting seed. When Jake and his wife and co-farmer, Dawn, took over in 2004, they didn’t see as many earthworms as they do today, but they are still working to build up the soil’s organic matter. The main strategy, he says: “We don’t leave anything bare. We’re big on cover crops.”

When Jake’s fields aren’t hosting crop plants, the soil surface is protected from winds and rains that would erode his soil by sequential plantings of cover crops. Cold-hardy rye that he plants in late summer provides a green blanket throughout the winter months. Near the end of winter, Jake broadcasts red clover seed amongst the rye grass. A nitrogen-fixing plant, clover will fill in the rye planting as spring progresses until it is time to till both plants under, adding carbon and nitrogen to the soil.

Then, during the growing season, his land is occupied by cash crops—a diverse menu of organic vegetables and sweet corn—or a hybrid grass of sorghum and sudangrass that can reach 12 feet tall and, after a single mowing, will plunge roots over a foot deep into the soil. All that biomass is the product of photosynthesis, by which plants pull carbon out of the atmosphere to build their bodies. When the hybrid grass is tilled under or killed by winter, that carbon-rich cover crop will become soil organic matter.

“This place is the model of soil conservation,” Jake says, with a hint of humility. He’s right and, although cover cropping has been a standard in organic farming systems for decades, the model has been making inroads into “conventional” agriculture for all of its no-brainer attributes, from soil and water management to weed, and even pest control.

What is being demonstrated at Maplestar Farm is that a carefully managed cover-cropping system can increase soil carbon content even while relying on tillage to prepare planting beds. Good to know because tillage is a primary cause of soil degradation and modern agriculture relies on the practice.

Tillage is the mechanical churning up of soil prior to planting, which destroys existing competitor plants (aka weeds) and makes the soil crumbly and easy to plant into. Tilling also allows ready passage of water and air to the growing crop roots. The problem is that loose soil tends to blow or wash away and the oxygen that is stirred into the soil promotes the rapid breakdown of organic carbon, which is then released into the atmosphere as carbon dioxide. Once the organic component of soil is gone, the soil’s ability to soak in and retain precipitation while remaining friable is diminished, and there is nothing to sustain the soil’s nutrient-cycling decomposer community.

There is two to three times more carbon stored in soil than found in the atmosphere . . . for now. Earth’s soils are estimated to have lost 8% of their total carbon during the last 200 years as a result of human mismanagement of land. “Modern” agriculture is responsible for nearly one-third of greenhouse gas emissions, half of which are released directly from soil.

Repeated tillage without careful management of soil carbon is a sure pathway to soil that is lifeless mineral dust and a climate that is unpredictable and extreme, two scenarios that are at odds with the underpinnings of agriculture. The good news is in the reversal: Agricultural practices can be adopted that remove carbon from the atmosphere and sequester it as soil organic matter, which thereby also improves soil health. The movement to adopt such practices, insofar as it exists, is called “regenerative agriculture.”


Pastured animal agriculture avoids tillage, and there is promise in no-till grain cultivation. But among produce farmers the predominant belief is, to quote a now-former Northeast Ohio farmer, “no till, no vegetables.”

Enter Matt Herbruck.

“I’ve gone all no-till pretty much,” he says.

An organic produce farmer for nearly a quarter century, Matt relocated his farming activities from coastal Maine to Hiram Township in 2009. He purchased some weedy fallow acreage and promptly plowed and tilled it, bringing Birdsong Farm into existence.

For years he stuck to a typical tillage-based organic agriculture, preparing planting rows by fluffing up the soil, adding organic fertilizers during the growing season and, in autumn, rock powders and other sources of mineral nutrients as prescribed by soil testing. “I read the paper at the same time every day, I eat breakfast at the same time every day, I prepared my fields the same way every spring, and it was hard to break that habit,” he says.

But one season pushed him to try something new.

“In 2016, I kinda hit a real rock bottom in terms of my enjoyment of farming. I had some fertility issues, and then that year [there was] like 100 days with no rain and it was like 90 every day and I knew at that time that I either had to really radically change what I was doing or quit farming because I hated it. I couldn’t take the heat anymore. And that’s when I started looking into different ways of doing things, and the no-till thing jumped right out at me.”

Matt’s new and developing system relies on reusable plastic tarps, covering 40-foot by 100-foot planting areas for several weeks in early spring. Prior to rolling out the tarps, he breaks up compact soil using a broadfork—a row of downward-pointed tines with two shoulder-width wooden handles that the user holds onto while driving the tines into the ground and leaning back. The action tilts chunks of soil, allowing air and water deeper into the soil, but keeps the basic soil layers intact. When the tarps are removed, a half-inch layer of compost is spread over the beds, which are then planted.

Matt is discovering many benefits to this new way of farming, some unanticipated. He’s seeing more earthworm activity, and after rains his heavy soil remains friable. Weed suppression is working better than expected. Whereas tilling exposes buried weed seeds to the surface, where they germinate, tarping warms the soil, prompting weed seeds to germinate under the opaque plastic. Matt’s weed pressure is so diminished he’s able to quickly replant a bed after harvest, and thereby downsize the acreage he’s farming.

“You can make the same money on 5 or 6 [acres] as you can on 10 if you have less employees. Really I was just working [those extra acres] to pay employees [to weed]. And also with this notill conversion I’ve been [able to] grow so much more stuff in a smaller footprint,” he says. He plans to use some of his newly fallow land to establish his own larger-scale composting systems, to off set the 5 tons he’s been purchasing.

Matt’s also nearly abandoned the one-time-use plastic row covers he once relied on to suppress weeds and retain moisture. He estimates he used to throw away 3 acres of plastic annually. “I couldn’t sleep at night. It just goes to the landfill. It’s terrible.

“It’s so easy to get into a rut with what you’re doing,” he continues. “I’ve been certified organic for 20 years, but that doesn’t mean that that’s the be-all-and-end-all of what you should be doing. I was doing a tillage-based system and I was depleting my carbon—my organic matter—far quicker than I was replacing it, and I saw a serious fertility decrease.”

Perennial crops lend themselves to no-till and are another interest and challenge. Matt shows me new asparagus and strawberry beds, heavily mulched with straw. Perennial crops would be the ultimate in harvesting food without disturbing the soil, and it is the focus of ongoing crop research. The Land Institute, for example, is working to develop a suite of perennial grain, bean, and oilseed crops—a food-producing assemblage of crops that could mimic natural plant communities, all in the name of soil rehabilitation.

What’s notable about Jake and Dawn at Maplestar Farm, Matt at Birdsong Farm, The Land Institute, and the many farmers adopting practices that regenerate soil by transferring carbon from the atmosphere back into the soil is their focus on improving the situation rather than simply avoiding harm. As Jake Trethewey forthrightly put it: “You hear this term everyone likes to throw around—you know—sustainable. What does that mean? Sustainable means treading water. We don’t tread water here, we get better. Our goal is, when we leave, this place will be in better shape than when we took it over.”

Speaking of treading water. Four years after it rose from the ocean, Hunga-Tonga Hunga Ha’apai still exists, one of only three newly formed islands in 150 years to have persisted longer than a few months. Indeed, waves have eaten away at its southern coastline while rain has gouged sharp gullies out of its slopes, but some of what has been washed away from near the island’s peak has collected downslope, where a sparse vegetation has taken root, seeded by birds that are nesting on the island. Researchers from NASA continue to monitor and re-evaluate the future of the island, but the optimistic outlook is that it could last another 25 years or so.

As for the outlook for human food production, there will need to be another kind of groundswell. Without a global shift to preserve and rebuild soil, given current rates of soil loss and degradation, humanity can hope to continue soil-based agriculture for perhaps another 50 years.