The rise in popularity in “local grains” prompted further research in organic growing practices for Ellen Mallory, Extension professor and Cooperative Extension agent with the School of Food and Agriculture at the University of Maine. Mallory presented “Organic Grain Research Mashup” earlier this year at the New York Certified Organic meeting to share her findings.

To grow quality, high-yielding grain, it takes the right variety, soil fertility and weed management.

“Clover is the fertility engine of organic grain systems,” Mallory said. Medium red clover, also known as multi-cut red clover, is widely adapted, winter hardy for Zone 4 and warmer and may be used as forage, for grazing and for plowing into the field for nitrogen. Its seeding options are frost seed or broadcast. Medium red clover produces plenty of biomass and up to 70 to 150 pounds of nitrogen per acre with 50% of it available in the first month after plowing it down.

Mallory said that planting red clover for its nitrogen is one option for people who don’t have a supply of manure from raising livestock.

But red clover can interfere with grain harvest. It has poor persistence in the second year and rapid nitrogen mineralization.

In her 2017-2019 trial of “green manure,” Mallory looked at mammoth red clover, New Zealand white clover, alfalfa and mixes with perennial ryegrass.

Mammoth red clover, also called single cut red clover, is shorter that medium red clover. It offers more root biomass and higher root percentage of nitrogen. New Zealand white clover is an intermediate type, also known as huia. It is shorter than medium red clover and increases its root biomass in its second year. Alfalfa offers a higher shoot percentage of nitrogen and a lower root percentage of nitrogen.

Organic grain research update

The green manure trial at the University of Maine Rogers Farm in October 2018 shows a comparison among different legume species (medium red clover, mammoth red clover, New Zealand white clover and alfalfa) inter-seeded into barley for their ability to supply nitrogen to a following wheat crop. Photo courtesy of Ellen Mallory

The green manures were broadcast at barley seeding. The clovers were sown at the rate of 12 pounds/acre. The alfalfa was 15 pounds/acre, mixes were at two-thirds rate and the ryegrass at 10 pounds/acre.

At the end of Year 1, the medium red clover planted with barley outperformed all the other treatments for biomass; however, by Year 2, the alfalfa surpassed it slightly, with mammoth red clover not far behind. For nitrogen production, medium red clover outshone the rest of the treatments in Year 1, but was surpassed by mammoth red clover, followed by alfalfa, in Year 2.

“The overall take-home is there are alternatives to medium red clover,” Mallory said. Although alfalfa is slower growing, it did well by Year 2.

Winter survival of grains relies upon a variety of circumstances. These include weather and climate conditions, such as snow cover, soil temperature, thawing, ponding and icing. Management also matters, including surface residue, pre-plant fertility, variety, seed quality, seed depth, seed date and seed rate and plant development going into winter.

Site characteristics are important as well, such as soil type, field slope, dips, soil pH, soil nutrients and compaction. All these affect the performance of the crop. Despite the challenges of growing winter grains, Mallory said that they offer many benefits, especially for organic growers.

“You can mix up the rotation, reduce weeds and you don’t have to do anything in spring,” Mallory said.

But the biggest issue is winter kill. “It’s been challenging,” Mallory said. “Sometimes, there’s nothing you can do about it. Sometimes, there are things.”

Choosing the right variety, including one that resists snow mold, can help prevent winter kill. Reducing weed pressure in early spring can also help, such as tine weeding.

“That’s what most growers in Maine do for organic small grains, but timing is important,” Mallory said. The grain must be large enough to tine weed, for example, and the fields dry enough to enter.

Mallory has also observed inter-row hoeing to reduce weed pressure, as well as weed clipping to reduce weed seed production. Her research group simulated this effect with scissors on a small plot, but “we did not have a very good year,” Mallory noted. Cultivators did a better job to reduce weeds.

Mallory also mentioned cross seeding to reduce weed pressure because the desired plants create a thick canopy to shade out weeds.

“Others seed while drilling to get a more uniform start,” Mallory added.

by Deborah Jeanne Sergeant