Organic no-till research spreading across the Midwest
From Pennsylvania to Michigan to Illinois, organic no-till is gaining ground as part of a revolution in weed management research and extension.

By Laura Sayre

Posted June 2, 2005: "Maybe we got lucky, but it worked beautifully. Weed control was excellent."

That's how Michigan State University extension specialist Dr. Dale Mutch sums up his first year trying out an organic no-till system using a cover crop roller based on the one designed and built at The Rodale Institute®. Drilling feed-grade soybeans into knocked-down cover crops of cereal rye and hairy vetch, Mutch and his team obtained yields of around 60 bushels per acre—in a year in which average soybean yields in their area were just 40 bushels per acre.

Needless to say, results like that have been attracting attention. Since the 2004 soybean harvest, Mutch says, he's presented the results of the trial to a total of about 125 organic farmers and 75 conventional farmers—and has gotten enthusiastic responses from both groups. "I've got a lot more guys interested in organic now than ever before," he notes, "especially with organic bean prices as strong as they are."

While Mutch remains cautious about recommending the new system to farmers, he's eager to subject it to a second year of testing in his research fields at the Kellogg Biological Station (KBS) in Hickory Corners, Mich. "We're on a sandy loam soil," he points out—farmers on different soil types may experience dramatically different results. And again, they may have gotten lucky with the weather: "Last season it rained every day in May," he says—conditions that favored no-till over standard tillage and that helped produce thick, vigorous cover crop stands. This season, too, the system will spread to Illinois, where one of Mutch's former post-docs will be working with another, identical roller at a USDA-Agricultural Research Service station in Urbana.

Carpe diem

"We'd been playing around with [organic no-till systems] for a number of years," explains Mutch, who specializes in cover crops and IPM for low-input and organic farming systems and manages eight OCIA-certified organic research acres at KBS. Originally, they tried drilling soybeans together with winter annual rye. With the rye planted off-season from its normal habit, it was retarded in its growth and served to hold back weeds without providing too much competition for the soybeans. "That worked really well the first year," he notes, "but the second year was a drought year, and it didn’t work." (They published a paper on the results in the January 2004 issue of Agronomy Journal: Utility of Interseeded Winter Cereal Rye in Organic Soybean Production Systems.)

Next, the team tried chopping a rye cover crop with a flail mower and planting into the residue. Around the same time they learned about The Rodale Institute's front-mounted roller-crimper, and they were immediately interested. After consulting with TRI farm manager Jeff Moyer on the details and obtaining a small grant from Michigan's Project GREEEN (Generating Research and Extension to meet Environmental and Economic Needs www.greeen.msu.edu), Mutch had his technicians build a roller in spring 2004 and immediately put it to work.

As luck would have it, the research station had some cover crop trial plots that had been established in late summer 2003, including plots of hairy vetch (sown at a rate of 45 pounds an acre on Aug. 15) and rye (sown at 2 bu/ac on Sept. 9). Mutch and his team set up a randomized complete block design with four replications of two treatments, one for the hairy vetch and for the rye. Both the rye and the vetch plots were rolled down on June 4, 2004; four days later, soybeans were drilled on seven-and-a-half-inch rows at 180,000 seeds/acre (the bean variety was Pioneer 92M10). There were no additional fertility amendments and nor any supplementary weed control. The beans were harvested on Oct. 7. Yields were excellent in both treatments, although they were slightly higher in the rye (62 bu/ac) than in the vetch (58 bu/ac).

As with any new system, there were some hiccups. Although the Michigan team initially planned to front-mount the roller, as the Rodale farm team has done, they had so much trouble sourcing a front-mounted three-point hitch that they eventually decided to rear-mount the implement and resign themselves to a two-pass rather than a one-pass system. (They even tried driving backwards so that the roller could roll ahead of the tractor tires, but they quickly abandoned that strategy as impractical.) "In organics you might have ten trips across the field," says Mutch. "We had two."

Mutch's team also experimented in 2004 with some spring-seeded cover crops, including oilseed, radish and oats, but didn't have much success with them. For 2005, they'll be testing eight treatments, including wheat and triticale as cover crops but continuing, for now, to work exclusively with soybeans as a primary crop. ("Corn is more of a challenge because we plant earlier," he says.) Although with their roller already in hand the Michigan researchers have a jump on the other participants in The Rodale Institute's No-Till Plus Project, Mutch says he plans to stay on schedule with the rest of the group by establishing on-farm test fields of cover crops in the fall of this year and beginning data collection in collaboration with participating farmers next year. "Our hope is to use the data from this year to give the farmers good recommendations for 2006," he explains.

On to Illinois

While Mutch is continuing his organic no-till trials this season in Michigan, he's also had a hand in expanding the system further west. In 2003 and 2004, weed ecologist Dr. Adam Davis held a post-doctoral position at the Kellogg Biological Station and worked with Mutch on the organic no-till trial among other projects. Because the system showed such promise, Mutch and Davis had a second unit built and delivered to the USDA-ARS Invasive Weed Management Unit in Urbana, Ill., when Davis accepted the position there.

"Organic no-till is the holy grail, and this is such a great tool," says Davis enthusiastically. "From early on we were pretty excited to see what it was going to do. When I came down here [to Illinois] I knew it was work that I wanted to expand on."

Davis plans to replicate the Michigan system, drilling soybeans into rolled-down rye and vetch covers. Whereas Mutch's work focused exclusively on organic no-till, Davis's research will include both organic and low-input methods. "I'm looking across the spectrum from purely organic to someone who is going to use [the roller] along with other tools," he explains. Within each cover crop treatment there will be a zero-herbicide treatment, a half-rate herbicide treatment, and a full-rate herbicide treatment. (In future years, Davis says, he may add treatments to test even lower herbicide rates, like one-quarter or one-third.)

As a weed scientist, Davis also plans to investigate the underlying ecological issues suggested by the use of the cover-crop/no-till system as a weed management tool. As he puts it, "I'm also trying to ask the why questions: If it is suppressing the weeds, then what's the mechanism by which that's happening? So we'll be measuring light infiltration, soil moisture, soil temperature and phytotoxicity from the cover crop residues both pre- and post-rolling and pre- and post- herbicide applications." In addition, Davis will work with an entomologist and a pathologist to begin looking at how low-input no-till interacts with pest and disease factors.

Like the Michigan group, Davis's team is still figuring out how best to manage the cover crops within the new system. This spring they rolled both the rye and the vetch in the first week of May, then rolled the vetch a second time on May 18 because it hadn’t gone down completely. (The rye went down well, even though they had a thick, six foot-tall stand to contend with.) "We had a really dry fall here and didn't get a very good stand of vetch," he says. "This year we're going to plant the vetch earlier, maybe as early as mid-August, to make sure we get adequate moisture to germinate it." Despite the dry weather, Davis reports that soil moisture in the cover cropped plots appeared to be similar or perhaps even better than in the bare-ground control plots.

Part of Davis's learning curve, naturally, has to do with adjusting to different soil conditions—exactly the process farmers would go through in adapting the roller technology to their individual farms. The silty clay loams at the Illinois research station are much heavier than the coarse sandy loams at the Kellogg Biological Station, Davis says, which means that—especially in dry conditions—a heavier roller is needed to get the same ground penetration with the crimping fins. "At first it seemed like the roller was bouncing—it worked better after we filled it with water," he says. "It made me wonder whether a larger diameter roller wouldn't work better [in these conditions].

"Unfortunately, with just two different soil types"—at the Michigan and Illinois research stations—"we probably won't be able to develop any general rules for matching roller methods to soil conditions," Davis continues. But with cover-crop roller testing now going forward in at least four states and scheduled to begin in half-a-dozen more, the formulation of such guidelines is surely not far off.

Farmers first

Another strategy Davis brought with him from Michigan has to do with research methods that foreground farmer involvement. Although the Agricultural Research Service has no formal extension mission (in theory, ARS researchers are supposed to be fed research problems by the land-grants and then feed solutions back for dissemination through university extension networks), Davis says, there's still room for interaction. Since arriving in Illinois last August he's been eagerly forging links with local farmers. "I work with farmers because I like working with farmers," he says, "and because farmers have great ideas for research questions."

"I work with farmers because I like working with farmers," says ARS weed ecologist Adam Davis, "and because farmers have great ideas for research questions."

As an example of that methodology, Mutch and Davis worked together on an MSU Extension Bulletin on integrated weed management that relied heavily—and intentionally—on farmer input. Davis, Mutch, and three other Michigan State colleagues assembled a group of a dozen successful Michigan farmers, half of them organic and half conventional, to talk about non-chemical ways of managing weeds. "We spent four, eight-hour days generating content, basically doing a brain-download from the farmers, asking them, 'What do you use? What do you wish were around that isn't? What have you heard about but need more information on?'"

Davis then spent eight months following up on those leads, searching through journal articles and other scientific publications to gather the latest, best information on weed management, broadly conceived, and then pulling it all together in an accessible format. The result is a 120-page, full-color book titled Integrated Weed Management: "One Year's Seeding…" and featuring a wealth of practical, innovative ideas and recommendations.

BOOK DETAILS

Integrated Weed Management
"One Year's Seeding..."


Cost: $10 ($7 each for orders of 10 copies or more)

Order online from the MSU Extension Materials Distribution Center or by calling 517-353-6740.

Reference extension publication number E-2931.

"A project like that had been a dream of mine for a while," Davis reflects. "One of my frustrations as a student and a researcher is all the good information that gets locked away in journals and in libraries," unavailable to farmers and even to extension personnel. The situation is exacerbated by shrinking extension budgets, which force agents to serve wider areas and broader farmer constituencies. "I look at my extension friends and realize that they just don't have time to go to the primary material," he says.

Another of Davis's goals was to highlight some of "the truly excellent work that my mentor, [Iowa State University weed ecologist] Matt Liebman, has done. His textbook, Ecological Management of Agricultural Weeds, is one of my bibles. There are lots of great [weed management] stories in there, but it's not something a farmer is going to pick up at the end of the day." In a sense, Davis says, One Year's Seeding is "a comic book version of that"—one that's heavier on the tools and includes lots of pictures and graphics.

A final objective was to tap farmer expertise in a state that today boasts significant numbers of successful, medium-to-large scale organic farmers, particularly in the center of the state and in the "thumb" of the Michigan mitten, according to Dale Mutch. "We've got five or six farmers with 2500-acre organic operations," he notes. "These are some very experienced, high-level producers" with a lot to contribute to their fellow producers in Michigan and elsewhere.

IWM: Integrated weed management

The Rodale Institute's organic no-till cover crop roller is featured in the One Year's Seeding book as an example of a weed management strategy that goes hand in hand with soil improvement. But it and other strategies described there also reflect a larger revolution taking place within the discipline of weed science, Davis says. On the one hand, the rise of genetically engineered herbicide-tolerant crops like Roundup-Ready soybeans has left a previous generation of chemically oriented weed scientists feeling like they've been made redundant. On the other hand, that reorientation has opened up an opportunity for a total rethinking of the possibilities of weed research. And a new generation of weed scientists, trained in ecological principles and responsive to the needs of organic and sustainable farmers, is rising to that opportunity.

 

"In the 'eighties and even into the early 'nineties, weed management meant thresholds," Davis explains—the idea of weighing the expense of weed impacts via yield losses versus the expense of herbicide applications to reduce those impacts. Unfortunately, "In most cases, when the analysis was done the actual threshold level was so low that you just had to spray all the time."

The new weed science—as pioneered by Liebman at Iowa State, Dr. David Mortensen at Penn State and many others—adopts what Liebman has dubbed the "many little hammers" approach—marshalling a wide variety of weed management methods that together can weaken and reduce weed populations over time. The ultimate goal, Davis argues, is to assemble a truly integrated, "multi-tactic weed management system" including everything from improved mechanical implements (like more flexible cultivators) to biological management strategies (like protecting insects that eat weed seeds) to microbiological effects (like encouraging microbes that hasten weed seed decay).

In contrast to technologies like Roundup Ready, integrated weed management seeks to improve farmers' bottom line by widening their skills and knowledge, rather than by inviting them to buy expensive patented inputs. "Farmers have made a Faustian bargain with the input suppliers," Davis observes. "They're accepting pay as heavy equipment operators rather than as ecological system managers. I think that's sad for a couple of reasons, first because they're never going to make a good living doing that, and second because it doesn't seem like a very interesting way to farm.

"I look at [integrated weed management] as a way of doing an end-run around the input suppliers. You ought to be paying yourself for being a good manager rather than paying someone else to supply you with inputs."