Pat Carr

Pat Carr, MSU superintendent and associate professor of cropping systems at Central Ag Research Center, spoke at a former field day at Western Triangle Ag Research Center.

Montana State University scientists spoke about some of the research they’ve been conducting in 2020.

Pat Carr, MSU superintendent and associate professor of cropping systems at Central Ag Research Center, spoke on various topics, including tillage versus no-till in organic production.

How can we expand no-till in organic production?

Both Carr and Perry Miller, MSU professor of cropping systems, have studied organic agriculture, included no-till.

“Organic no-till has a place. Perry and I, along with many researchers, were looking at organic no-till. In Brazil, they have organic no-till cover crop,” Carr said.

The mulch remains on the surface for weed suppression.

Carr studied organic no-till more than a decade ago when it was considered a “hot topic.”

They discovered there is a 4- or 5-year window before weeds would overwhelm the field.

“The weeds that do it are the perennials, bindweed, or creeping thistle,” Carr said. “Once those perennial weeds become established, there really isn’t a cover crop you can grow or a mulch that can suppress that. It is hard to keep weeds out.”

In conventional farming, herbicides are used, while in organic farming, tillage is often used to keep down weeds.

“In terms of an organic, no-till system in a large state like Montana, that system relies on a roller crimper and blades to kill the cover crop,” he said. “When you think of that and you think of the size of Montana farms, running a roller over all that land would be difficult.”

Using a roller works best on level land.

Bringing in animals to strategically graze the perennial weeds works in an organic no-till system, at least for a few years. Then, organic farmers would probably need to “strategically use tillage,” Carr said.

Zack Miller, MSU superintendent at Western Ag Research Center, said studies need to be conducted on how organic no-till farmers can manage perennial weeds.

“There is a fundamental mistake with dryland and growing cover crops to suppress weeds. In the Northern Great Plains, including Montana, where it is semi-arid, it is often difficult to grow a large biomass of cover crop to suppress weeds,” Miller said.

The limiting factor to ag production on dryland in the Northern Plains is precipitation.

“If you can do that (put down a lot of biomass in cover crops), you use up the water and we are in a water-limiting environment. You use up the water for the following crop, so that crop won’t grow very well,” he said.

Even in the Bozeman, Mont., area, where there is more precipitation than in eastern Montana, they needed a good moisture year to be successful with the no-till organic experience.

“We were successful with a 36-month organic no-till with a five-year rotation when there was good moisture,” Perry Miller said. “There is a reason we are studying perennial weeds at that site.”

The scientists talked about using sheep versus cattle to graze and eliminate the weeds in organic no-till.

“Most of the work we have done is with sheep,” Zach Miller said. “Anecdotally, I can say in our trials with sheep that they prefer bindweed and that backs up work done in the 40s and 50s.”

With beef cattle, there is more difficulty getting down and eliminating all the weeds due to the size difference.

“The animals have to be put on (the weeds) at the right time when conditions are right,” Perry said. “It is fun research, but if you miss that window with timing, it doesn’t work.”