Last summer, veteran organic farmer Scott Park was bewildered when he surveyed his vast tomato, corn, and sunflower fields. Before planting the crops on 350 acres he had radically cut down on tilling the soil, planted cover crops twice, and let sheep graze the land. And he was sure he’d see excellent yields.

The undisturbed soil was loaded with earthworms, but the crops grew sluggishly and didn’t produce enough fruit. Park lost almost half of his yields—and over half a million dollars.

“We thought we were going to cut a fat hog,” said Park, whose farm lies 50 miles northwest of Sacramento in California’s Central Valley. “But the combination of no-till and grazing kicked me in the teeth.”

Though surprising, the result was part of a critical experiment that Park plans to replicate again—this time, on a smaller plot on his 1,700-acre farm: Because there’s more at stake than his own profit.

Park, who has been farming for 48 years and is well-known for his soil health practices, is one of a small group of innovative organic vegetable producers working with the University of California Cooperative Extension, Cal State Chico’s Center for Regenerative Agriculture and California State University, Fresno to decipher how to farm with little or no tillage—and without chemicals.

For the vast majority of organic growers, tilling the soil is a crucial tool. It helps control weeds (which are a much bigger challenge for farmers who don’t spray herbicides) and helps incorporate compost and other nutrients into soil. But that system may begin to change.

Scott Park. (Photo credit: Chico State Center for Regenerative Agriculture)

The so-called no-till farming system, which is said to boost soil health, sequester carbon, and bring myriad other benefits, is popular among commodity grain farmers in the Midwest and the Northeast—many of whom rely heavily on herbicides and increasingly use the term “regenerative” to describe what they do. But even among those farmers, most haven’t cut out tilling altogether, alternating no-till with tillage practices.

Switching to no-till on mechanized organic farms—and particularly in organic vegetable cropping systems—has long been considered the holy grail, and practically impossible to achieve, especially in the water-parched arid West, a region that dominates U.S. organic produce production.

Two growing seasons into the California experiment, Park and the other farmers have faced an array of challenges. Some have been economically painful, while others have led to promising results. And yet, if the farmers can get past the hurdles presenting themselves in these early years, their efforts could catalyze a massive shift to reduced tillage—and a new understanding of soil health—in the organic industry in California and nationwide. And because no-till is held up as a central tenant of regenerative agriculture, it could also be seen as a boon for farmers hoping to take part in the carbon markets the Biden administration has put forward in response to climate change.

“When soil transitions to a no-till system, yield reduction is usually a temporary thing,” said Cynthia Daley, a professor at Chico State who is involved in the project. “These farmers see the benefit of going into no-till, but they are trying to find a way to get there that doesn’t result in a negative economic impact in the long run. Their dedication is incredible.”

No-till could also create a carbon sponge to retain water in the soil and cut back on evaporation, a change extremely welcome in California, where water is scarce and droughts are common, said Paul Muller of Full Belly Farm, another farmer participating in the no-till experiment. The cooling effects on soil would also be crucial, Muller said, given that hot temperatures can negatively impact the soil’s microorganisms.

“We’re trying to figure out . . . whether there’s a better system without tillage where we can empower the microbial communities under those plants to supply them with what they need,” said Muller. “We’re at the beginning of that curb of knowledge and of understanding how these practices can capture more carbon and put more vitality into our farming system.”

No-Till Catches on with Organic Farmers

Intensive tillage on a large scale took off in the U.S. with the invention of the steel plow in the 1830s. But while it facilitated the conversion of prairie land and large-scale farming across the country, tillage also led to massive erosion, habitat loss, and the release of greenhouse gases. It culminated in the Dust Bowl of the 1930s, an agricultural crisis so severe that it caused some farmers to adopt conservation practices and the U.S. government to invest in teaching them how to take care of their soil through the U.S. Department of Agriculture (USDA)’s Soil Conservation service, which eventually became the National Resources Conservation Service (NRCS). And while those efforts convinced some farmers to change their practices, most continued to intensively plow their fields multiple times each season.

No-till rose in popularity throughout several regions of the U.S. in the 1970s and today, its adoption is concentrated in the South, the Midwest, and the Great Plains. According to the 2017 U.S. Census of Agriculture, no-till was used on 37 percent of U.S. acres, and reduced tillage was practiced on an additional 35 percent. Since reducing tillage is part of a wider set of regenerative practices, some farmers are also planting more cover crops to regenerate their soil and prevent erosion. Cover crops use rose by 15 percent between 2012 and 2017, but they still only grow on about 4 percent of the nation’s total cropland.

On most farms, the phrase “no-till” is a misnomer, as many farmers use it to refer to a greatly reduced approach to tilling and not to the continuous lack of tillage. For this reason, teasing out the differences in approaches between regenerative and organic systems can be a challenge.

Some organic farmers have scoffed at the idea of no-till and regenerative agriculture systems that include herbicides. They argue that organic farming, which is built around the idea of soil health, can build up soil fertility or sequester carbon better than regenerative/no-till agriculture. Some research indicates this is true because the addition of manure and cover crops more than offset losses from tillage.

Other research shows that organic farms’ ability to store carbon at deeper soil levels exceeds that of conventional farms, even those using cover crops. Scientists are still learning to understand how soil works, so the jury is out on whether organic production that includes tilling but cares for the soil in other ways equals or outstrips no-till farming.

While science continues to evolve, a third of all organic farms nationwide self-define their operations as “no-till” or “minimal till”—but, as is the case for conventional growers, for most, these terms don’t mean that they have stopped tilling.

The “organic no-till” project at the Rodale Institute, is a good example. The Institute has been working since the 1990s on ways organic grain growers can disturb the soil less.

“On one hand, organic farmers claim to be improving soil health, but with the same breath they’re doing multiple tilling operations in a single season,” said Jeff Moyer, Rodale Institute’s executive director. “Tillage day isn’t a particularly good day if you’re an earthworm.”

Moyer, who spent 35 years as Rodale’s farm director and farm manager, began encouraging large organic grain growers to plant cover crops prior to their cash crops and to use the residue as mulch to suppress weeds. To facilitate the process on large farms, he re-designed the roller crimper as a tool to help organic corn and soybean farmers reduce tilling. Hitched to a tractor, the crimper flattens cover crops, breaking their stems and creating a dense mat of mulch. With the right tool, the farmer can then plant the cash crop directly into the newly rolled mulch.

A no-till roller-crimper. (Photo credit: Rodale Institute)

A no-till roller-crimper. (Photo credit: Rodale Institute)

This system has allowed some organic farmers, mostly in the Midwest, to reduce their tillage—cutting it down to one deep-till pass per crop rotation. In the past, those farmers would make a primary tillage pass over their fields, followed by multiple secondary passes to disc, pack the soil, make a clean bed ready for planting, and then—once the crop is growing—to rotary hoe and cultivate multiple times to manage weeds.

“To the microbial life in the soil, it feels like tillage over and over again, and that’s what we’re trying to avoid,” Moyer said.

In addition to the tillage to establish the cover crop, Rodale’s system reduces multiple passes through the fields to just two, planting and harvesting, Moyer said. And farmers time the deep tillage for late summer, when the weather is dry and the earthworms and other soil life burrow deep in the soil in search of moisture. They also apply compost, manure, or other soil amendments, which—in addition to the benefits derived from the cover crop—reduce the negative impacts of deep tillage, he added.

The roller-crimper system has worked so well for organic grain corn and soybean that some conventional soybean growers are also using it to reduce their use of expensive herbicides, said Moyer, who is also the author of the newly published book, Roller/Crimper No-Till.

The approach has gone from total obscurity to adoption by organic farmers on millions of acres—mostly in corn and soybeans, but also on orchard and vineyard floors, Moyer said. Other institutions, including the University of Wisconsin-Madison, Washington State University, and Iowa State University, are also conducting research on reduced tillage in organic farming using the roller-crimper.

Organic Pioneers Form No-till Partnership

In California, organic vegetable growers have made multiple attempts at reducing tillage over the past decade, with little luck, said Tom Willey, an organic pioneer who retired three years ago from his 75-acre farm near Fresno. Willey, who farmed for nearly 40 years, is now helping other growers return to the effort.

A historical photo of Tom Willey in his farm field.

Tom Willey holding soil from his farm.

“Our early attempts at no-till were so disappointing, we gave up,” Willey said.

Then, in 2018, three well-established organic farms, Scott Park’s farm Park Farming Organics, Full Belly Farm, and Pinnacle Organically Grown Produce joined forces with U.C. Extension, Cal State Chico, and Fresno State to launch on-farm trials focusing on various forms of reduced soil disturbance. Since then, with financial support from a USDA NRCS Conservation Innovation Grant (CIG), the farmers and researchers are trying out various approaches and equipment. While the farmers choose which practices to use, the universities are collecting soil and tissue samples and doing additional reduced till and cover crop experiments on the schools’ farms.

The partnership is especially significant in a state that has always been at the forefront of organics but has offered little to no research development or extension services to organic farmers.

The participating farmers have all grown cover crops, incorporated compost, and managed complex crop rotations for many decades; they have all also experimented with reducing tillage. Yet, in a sense, they have decided late in their careers to go back to farming school, putting aside prevalent, economically secure concepts of organic production to learn a more nuanced, complicated version of soil microbiology. It’s a significant risk, but one they hope will be worth it.

“It’s like looking at the world through a different lens . . . a more reverential one that says we don’t know a whole lot and we should stop screwing it up. And maybe it can teach us if we step back,” said Muller of Full Belly Farm.

The farmers and academics are part of a growing informal network that shares knowledge, swaps scientific papers and on-farm trial updates, organizes farm tours, and hosts a slew of soil health experts, including conventional no-till farmers.

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