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November 20, 2003: "'I thought you
guys were organic!'" So said one of The Rodale Institute's
(TRI) conventionally farming neighbors earlier this year,
after seeing TRI's freshly planted soybean field. Rodale Farm
Manager Jeff Moyer had knocked down the cover crop of rye
and planted the beans directly into the residue. "It
looked so good and the kill was so complete, he thought it
must have been sprayed," recalls Moyer.
Rest assured, however--there were no chemicals involved.
Instead, Moyer used a new, front-mounted cover-crop roller
designed and built at The Rodale Institute® as part of
a continuing effort to develop practical methods for reduced
tillage organic production. The Rodale Institute Farm team
has experimented with no-till corn into mixed legume covers
as well as no-till soybeans into small grain covers, and is
greatly excited about the results. "We're moving toward
a situation in which we do our primary tillage to get our
cover crop established, so that [the cover crop] almost becomes
your primary crop, even though it's not for sale," Moyer
explains. "It changes the way you think about the whole
system."
Moyer has been using cover crops to supply nutrients, build
organic matter, and prevent soil erosion in TRI fields for
more than three decades, so for him the challenge of organic
no-till has lain not so much in managing the cover as in finding
the right equipment to knock it down and plant. In past years,
Moyer and his crew went after the job with a modified, ground-driven
Buffalo stalk-chopper and a 4-row, shoe-style Buffalo no-till
planter. Although that combination worked reasonably well,
it still left room for improvement. For 2003, TRI farmers
paired their innovative, home-made roller with a Monosem double-disc
no-till planter and achieved much better results.
"Last year, no-till for us meant the difference between
eight field operations for corn--plow, disk, pack, plant,
rotary hoe, rotary hoe, cultivate, cultivate--and two--roll
and plant," says Moyer. "This year, we cut that
to one," rolling and planting simultaneously. "That
really starts to get the attention of the conventional farmers,
because it addresses one of their major objections to organic,
that it requires more field passes. You can't get it much
lower than one pass."
TRI's cover-crop roller was constructed in collaboration
with another neighbor, John Brubaker. Brubaker's land lies
adjacent to The Rodale Institute property, and the two farms
frequently exchange labor, tools, and ideas; he has also worked
with TRI on equipment-development projects in the past. To
support his work on the roller he received a 2002 farmer's
grant from the USDA's Sustainable Agriculture Research and
Education (SARE) program. Brubaker is a skilled welder and
practical engineer--"I've been a shop-monger all my life,
that's what I've always loved to do," he confesses--but
he also brought a specific area of expertise to this project.
As a member of the Groffdale Mennonite Church (aka the 'Horse
and Buggy' Mennonites), which prohibits the use of rubber-tired
tractors and motorized road vehicles, he has always worked
with steel-wheeled tractors. And the cover-crop roller acts
a lot like a big steel wheel.
Building the right tool for the job
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Once you've seen how one pass with a roller can turn a lush
stand of rye and hairy vetch into a 5-inch thick, weed-suppressing
mulch, you'll wonder why anyone thought of introducing herbicides
into the concept of no-till. (A recent study conducted by
Sean Clark at Berea College, Kentucky, and reported elsewhere
in these pages www.ca.uky.edu/agc
/pubs/pr/pr470/PR470C.
HTM #vegetables, found similar results between knockdown
alone and knockdown with glyphosate, or Roundup, when planting
corn into a rye cover.) The goal is not to cut the stems but
just to crimp them and lay them flat, and the key is to wait
until the cover crop reaches full flowering. If you do it
before, the plant is still in a vegetative growth stage and
will bounce back green and vigorous, but if you get it after
that point, it will dry and die. "At least a 20% bloom
is suggested," explains Matt Ryan, a TRI research technician
who has worked on the no-till effort, "but we've found
it's better to wait for 50 to 75% bloom." As long as
any early-developing seeds are still green, they won't be
viable to create a problem in the next crop.
Modified stalk-choppers like the one Moyer was using before
have gained some popularity as cover-crop rollers, but they
do have a couple of significant shortcomings. First, any rear-mounted
roller is liable to perform unevenly because the plant material
won't receive the full impact of the roller where it falls
into the depressions created by the tractor tires. Second,
steering the planter accurately across the knocked-down residue
can be a challenge because the planter's row-markers can't
make a good line in the thick residue. To get around that
problem, the team even tried planting first and then rolling,
but before long they realized that a front-mounted roller
would resolve both issues--and have the additional advantage
of saving another trip across the field.
To design the new roller, Brubaker explains, they began "by
looking at what worked and what didn't work with the stalk
chopper." The stalk chopper's eight rolling drums arranged
in two parallel rows, for instance, meant sixteen sets of
bearings to maintain and as many snag spots for the cover-crop
material to get bound up on. The new implement's single cylinder
has just two bearings, and these are inset three inches on
either side and fronted with a smooth shield to reduce catching.
The stalk chopper has blades running parallel along the drums,
but Brubaker's familiarity with steel wheels led him to suggest
curving the roller's blades around the cylinder in a chevron
pattern, which prevents bouncing and helps guide the tractor
in a straight line (whereas curving the blades in a screw
pattern would tend to auger the tractor to one side). Brubaker
also knew that the blades should be angled back from the direction
of motion, because if they were mounted at a 90º angle
to the drum they would kick up soil as they left the ground.
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Other aspects of the design proceeded by the 'goldilocks'
method. The team chose a pipe 16 inches in diameter for the
drum, for instance, "because we thought anything bigger
than that was just going to look ridiculous on the front of
a tractor," as Moyer puts it, and anything smaller didn't
seem like it would do the job. Similarly, they settled on
4-inch blades "because six inches looked too big and
two inches looked too small." The roller's overall width--10
feet six inches--was determined by the width of planting four
rows on 30-inch spacings, with a three-inch overlap on each
end "just to be safe."
With these features in place, the team strove to make the
roller as adjustable as possible. Since they were starting
with a hollow pipe, they sealed it tight and inserted a removable
plug so that the drum could be filled with water to vary its
weight for different field conditions. All of the blunt, square-ended
blades are bolted in place instead of being welded so that
they can be removed or replaced as needed. And when choosing
the degree of twisting of the blades around the drum, Moyer
and Brubaker made it so that if every other blade were removed
there would still be continuous ground contact from one blade
to the next.
Field testing, and looking to the future
But the proof, of course, is in the field performance. Although
the 2003 crop yield and weed biomass data have yet to be analyzed
(at this writing the soybeans are still in the field), Matt
Ryan reports that "everyone was really, really impressed
with how well this [system] worked." Part of this year's
improvement was due to the new Monosem planter, which makes
a narrower planting strip in the cover-crop residue and thus
minimizes the potential weed zone. But the roller was the
star of the show. Moyer estimates that they got "at least
a 90% knockdown" with the new setup; and the roller easily
handled tough cover crop combinations, like hairy vetch and
rye, which caused lots of problems with the stalk chopper.
"The only change we might make is to add some tractor
weights to the frame" of the roller, says Brubaker, since
they found that in the toughest field conditions for knockdown--a
very dense stand of cover, on a dry soil--the implement wasn't
quite heavy enough even when filled with water.
Different types of cover crop also handle somewhat differently
beneath the planter, and another refinement the team plans
to make next year for vetch covers is to put small tires angled
around the planting row after the seed drop, to nudge the
plant material back over the exposed area. For the small grain
covers, they used toothed cultivator-type wheels for this
purpose, but the easily-snagged vetch needs something soft
and blunt. Ryan also suggests that if possible, small grain
covers should be planted perpendicular to the direction of
the main crop, so that the 6-inch drill spacings will be less
likely to get exposed in the knockdown process.
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After planting, a few weeds did eventually get through the
mulch, but for the most part these were delayed enough in
their growth that they posed no competitive threat to the
crop. "It's important to remember that beyond a certain
point, weed control becomes strictly a beautification process,"
Moyer emphasizes. "Small weeds are not going to affect
your crop yields." To handle the occasional aggressive
interloper in the no-till field, Moyer and his crew did a
quick and dirty trial of vinegar as an herbicide, tacking
some shields onto a two-row sprayer and running through a
few rows of the soybeans. "It would have worked better
if we'd sprayed the vinegar earlier," says Moyer, "but
you can see it did have an effect." (USDA researchers
John Teasdale and others have published initial experimental
results of using vinegar as an organic herbicide www.barc.usda.gov/anri/sasl/vinegar.html.)
For next year, The Rodale Institute researchers are planning
a more rigorous experimental trial to test the performance
of the no-till system versus plow-till. There's been some
talk of submitting a patent application for the new roller
design, but Brubaker waves off such commercialism and Moyer
stresses that despite its initial success, the tool is still
in the prototype stage. "There's a lot of tinkering that
could be done," he notes. "Maybe the blades should
be serrated, or sharpened, or every other one should be twice
as high. Or we might be able to plant on 15-inch rows instead
of 30, since a lot of the reason to have wider rows is so
you can cultivate." Seeding rates on the cover crops
could also be adjusted for different results. Interest in
the implement is mounting, however. "Jeff told me he's
already gotten a request for one," says Brubaker. "I
don't have that much time with my own farming, but I haven't
said no."
The organic no-till system has at least two potential groups
of farmers it might interest: conventional farmers who are
already doing no-till, and organic or sustainable farmers
who are already working with cover crops. Ryan notes that
for those already using covers, the barrier to trying no-till
is finding the right equipment--and the new roller design
could help with that. But for Moyer, the most exciting thing
about developing this new method is that it "really opens
the door to conventional farmers. When I talk to conventional
farmers, they say, 'I'd be ready to think about organic if
it could be no-till.' They all got rid of their moldboard
plows years ago." He even points out that conventional
farmers could incorporate cover crops into their no-till systems
while continuing to spot spray with herbicides or plant Roundup
Ready soybeans. After all, the new roller is just a tool;
and for conventional farmers to convert to organic is a big
step.
"Farmers are business men--they need to have a business
plan in place to make a change like this, they need to talk
to their banker, to their families, really think it over."
For that group, Moyer recommends trying out the system on
a small field at first--perhaps a rented field belonging to
a landlord wanting to see a reduction in chemical use. "A
lot of the farmers around here farm rented ground," Moyer
notes, "and that land base is dwindling" as the
owners give in and sell off to developers. "So the farmers
are saying to themselves, I need to figure out how to make
the same amount of money on half as much land. Going organic
could help them do that." 
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