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This cover crop radish isn't the same all the way down. Why not?

This cover crop radish isn't the same all the way down. Why not?
Soil compaction can be so tough that even cover crop radish roots are affected.

Look at the radish root in Barry Fisher's hand. Normally when people who grow radishes as a fall cover crop show a picture, it's of a huge radish with a root over a foot long and several inches in diameter.

Related: What's In Your Cover Crop Mix?

This one is a few inches in diameter for the first four inches underground, then skinnies down to a much narrower width as it moved farther down.

What is going on?

Note root shape: This radish root made it through compacted layers of soil, although the layers caused the roots to become narrower as they moved farther down.

"This soil here is really compacted from traffic connected to the Farm Progress Show," says Fisher, of the Natural Resources Conservation Service, based in Indiana. When we caught up with him, he was checking out a strip of cover crop sown just five weeks before the show for demonstration purposes. It was a mix of many varieties of cover crops, including radishes.

"What has happened here is that the radish hit a hard layer and couldn't continue growing that huge root on deeper," he explains.

So that's not good, right?

"What it tells us is that this site could benefit a lot from cover crops that root deep," Fisher says. "The fact that the radish was able to go on down through the compacted layer, even if it had to narrow up the root, says that it is helping to break through the hard, compacted soil."

You won't erase tough soil compaction with one cover crop or in one season, he notes. But it is a start, and a good way to begin returning soil health to any field or area of a field with soil compaction issues.

The mix also had annual ryegrass and several other crops coming up under the radishes. Due to good early growth, the radishes were covering up the grass cover crops underneath the canopy.

Related: Forage Radish, Annual Ryegrass Lead Cover Crop Race

In an Indiana or Illinois climate, particularly in northern parts of both states, radishes or turnips usually don't survive the winter, Fisher says. If you're using them to help put down roots and break up the soil, you may want to consider adding another cover crop that will make it through the winter.

If you haven't seeded radishes and several other cover crops, including annual ryegrass, by now, you need to do it soon, he says.

Cereal rye is the cover crop that can be planted until late October or very early November in most parts of Indiana and Illinois and still over winter into spring.

Related: 10 Tips for First-Time Cover Crop Success

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