Wednesday, March 30, 2011

A Missouri No-tiller's Quest

Source: No-Till Farmer, April 2011
By Martha Mintz, Contributing Editor

SOME DIG DEEP to identify the yield robbers on their farms. Jules Willott only
had to dig 3 inches.

After years of letting his fertilizer rep take his soil samples, the Mexico, Mo.,no-tiller decided to do the job himself. What he discovered as he dug his soil samples was a shallow compaction layer.

"There was good, loose soil for 3 inches, then a 1.5-inch layer that was hard and then good soil below that," Willott observed. "Our roots were getting through, but I think it must have slowed them down a little."

The 15-year no-till veteran wasn't convinced it was compacted enough to hurt yields on his soybean, wheat, clover and milo crops, but it was on his mind. When bad weather kept him from planting a crop in 2009, he decided to seize the opportunity to experiment with some compactionalleviating cover crops.

Montgomery City, Mo., regional extension specialist Richard Hoormann was more
than happy to help. He'd been looking for opportunities to see how cover crops that
had been successful in other regions would perform locally.

Together, they broadcast-seeded two timings of nine different cover crops on Willott's challenging claypan soils. Wheat, purple-top turnips, oil radishes; tillage radishes, annual ryegrass, Austrian winter peas, rape and other turnip varieties were planted in 22-by-125-foot plots.

Diverse Benefits

The cover crops were planted from August through October. They grew, winter killed and then Willott no-till grow deeper.

"They may also work to scavenge some nitrogen and phosphate from deeper in the
soil profile." Willott hopes these benefits can boost soybean yields. Milo and wheat are more profitable for Willott, but he drilled soybeans into the plots in spring of 2010.

Wet conditions in the fall of 2009 meant the later September and October seedings didn't emerge well. But the August-seeded covers grew well and showed several benefits.

"The radishes provided some weed suppression, which I didn't expect," Willott recalls. "In the spring of 2010, there were absolutely no weeds where the radishes had been used as a cover crop."

Hoormann noted that across the plots there was a lot of cheatgrass, Japanese brome and a variety of broadleaf winter annuals.

But the plots where tillage radishes, oil radishes or purple-top turnip were planted were virtually weed-free in early spring. He credits this largely to their broad rosette canopies blocking weed-seed germination.

"This would be a great benefit for those who want to use cover crops but want to do an early planting in the spring," Hoormann says. "They would be able to plant early without having to worry about burndown for a cover crop or weeds."

There were no weeds, but the radishes and turnips did leave 2- to 3-inch-diameter holes that extended through Willott' s shallow compaction layer.

"I'm definitely considering working them into my rotation and they should fit easily behind my wheat crop," he says. "It looks like they will be able to loosen up that compaction layer and serve as a channel to help guide the roots of my other crops to grow deeper.

"They may also work to scavenge some nitrogen and phosphate from deeper in the
soil profile."

Willott hopes these benefits can boost soybean yields. Milo and wheat are more profitable for
Willott, but he must keep soybeans in the rotation due to the allelopathic effect milo has on wheat. If they're going to stay, he wants to push them out of the 30-to-40- bushel yield range and into the 50-to-60- bushel yield range.

His cover-crop experiment may have put him on the right path. Besides compaction alleviation and weed suppression, soybean harvest brought another pleasant surprise
from the cover-crop plots.

"The yield monitor was bouncing around all over the place when I harvested," Willott
says. "Yields were higher in the cover-crop plots, especially where we planted the tillage radishes."

In four replications of the August timing, tillage radishes were shown to increase soybean yields by 3.5 bushels per acre. It isn't conclusive data, but it's a step in the right direction.

Willott volunteered his acres for another round of cover-crop plots last fall. Several other area producers are joining in, too, as part of a larger project to expand cover-crop
usage and education in Missouri.

Cover crops are already gaining strong interest from extension and producers. Willott's cover crop plots drew about 35 visitors during a 2010 field day despite heavy rains - a credit, Hoormann says, to the growing interest in cover crops in Missouri.

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