What started as an innocent mistake a few years ago on an Ohio farm could provide a substantial yield boost for winter wheat growers.
Dozens of growers throughout the Midwest have combined wheat and radish seed in their planters and drills and no-tilled the mix in onfarm plots to do side-by-side comparisons with wheat-only plots.
Wheat yields have increased by as much as 18 bushels per acre during early farm experiments. More onfarm results are expected in July when 85 farmers in Ohio, Indiana and Michigan harvest winter wheat planted last fall with radishes.
No-tillers want to know if yield increases from this mix are large and widespread enough to implement on a broader scale.
“We want to know when and where this works, why it works and how to manage it,” says Holtwood, Pa., no-tiller Steve Groff, who is supplying his trademarked “Tillage Radish” seed to the growers. “I’m thinking we’re picking up 10 to 15 pounds of nitrogen and giving it to the wheat.”

Possible Windfall

With current prices, the yield increases could add up to substantial profits for wheat growers — especially if the nutrient-scavenging benefits of radishes allow for a reduction in applied nitrogen on wheat acres.
For example, Groff’s Tillage Radishes cost about $3 a pound last fall, meaning it would only take a 1-bushel gain to pay for the radish seed if it was applied at 2 pounds per acre. The remaining 17-bushel increase, applied over 500 hypothetical acres of soft red winter wheat trading at $8.21 a bushel (April 20 price), would bring a $69,785 gross profit.
For hard red winter wheat grown in the southern and central Plains — which was being traded at $9.36 a bushel on April 20 — that translates to a $79,560 gross profit on 500 acres.
Even a modest 5-bushel increase at those prices on 500 acres would yield $16,420 gross profit for soft red winter wheat, and $18,720 for hard red winter wheat, with the cost of seed factored in.

A Good Mixup

The idea of seeding radishes and wheat together came about as a mistake.
A few years ago, no-tiller Ed Winkle, who owns HyMark Consulting, forgot to clean out his drill before seeding wheat on his Martinsville, Ohio, farm.
Two weeks later, he noticed radishes emerging with the wheat plants. Knowing the radishes would winterkill — which they did — Winkle left the fields alone. When he harvested wheat the next summer, he saw an 11-bushel increase where the plants grew with radishes.
Winkle and some neighbors did the same mixed seeding on a few plots the following year, seeding the plots with 2 pounds per acre of radishes. Wheat yields in those fields jumped by 8 to 18 bushels an acre.
Two small-scale research plots in New York and Illinois generated 5 to 12 bushels more wheat per acre last year.
It’s not clear why wheat and radishes planted together have boosted wheat yields, Groff says, but there are some theories.
“One of the big questions will be how to manage nitrogen,” he says. “We know radishes give up nitrogen a few weeks after the ground thaws out, which corresponds with the time wheat greens up. But that’s purely hypothetical.
“Maybe it’s something about the synergy created when you grow two crops together.”
Groff is also interested in finding out depth of the tillage radish roots vs. the wheat roots before dormancy, and whether the radishes are pulling up nitrogen to the wheat plants.
Less Applied N? David Brandt, a no-tiller from Carroll, Ohio, and Groff are helping to drive the multistate wheat-radish experiment. Brandt obtained a $4,000 grant from an Ohio organization to buy radish seed and distribute to about 20 growers.
But the list of participating farmers quickly grew to 45, then to 80. Groff has supplied seed to all of them and promised to zero-out the bill if farmers send him their research results. Each farmer was given about 50 pounds of tillage-radish and asked to plant it with wheat seed side-by-side with their regular wheat acres.
On Brandt’s farm last fall, two 15-foot drills were used to seed 150 acres of wheat, half of it seeded with wheat-radish mix at a rate of 2 pounds of radish seeds per acre.
Last fall was very dry in his region and the radishes were only 5 to 6 inches tall, so Brandt isn’t sure what benefit he’ll see.
In previous trials on his farm where the mix was planted, Brandt says he was able to reduce his nitrogen application from 100 pounds per acre in split applications to as low as 50 pounds per acre.
“We had some guys saying it was giving them 18-bushel increases, so I had to see if it works,” he says. “It only takes a 1-bushel gain to pay for the radishes, but we’ll need to see more of a benefit than 1 bushel to make it advantageous.”