Story Jenny Rees and Todd Whitney
University of Nebraska-Lincoln

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August 19, 2013
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Tips from the Experts: Planting cover crops into storm-damaged fields

Q: I’m considering planting cover crops into areas of corn and soybean fields with hail damage.

What are my next steps?

A: First, it’s important to consult your crop insurance provider to determine if you can do anything before the adjuster examines the field.

Next, look at your cover crop options, based on potential herbicide carryover from the previous crop and what your end goal is for the cover crop.

Herbicide Carryover

Herbicide carryover from the corn or soybean crop also can be a concern.

Check out the herbicide carryover replant options in UNL Extension’s Guide for Weed Management with Insecticide and Fungicide Information on pages 160-171, at www.ianrpubs.unl.edu/epublic/pages/index.jsp?what=publicationD&publicationId=941 .

To determine if herbicide carryover is a concern for your fields, first check the herbicide label(s) for potential problems.

If a rotation (waiting) interval is a concern, contact the chemical manufacturer and explain your conditions.

Although the label is the law, companies have conducted extensive research on their products.

Sometimes, they can give you a percentage survival chance for planting a crop within a cropping interval.

Producers will assume the risk if the germination of the next crop is severely affected, but it may be worth a small calculated risk to potentially get a cover crop established.

Home germination tests also can be conducted. (Planting delays with cover crops, though, may be a concern).

Simply take soil samples from the hailed fields and place into containers such as plastic cups with holes in the bottom.

Plant about 20 seeds per cup of whichever cover crops you are interested in and wait seven to 14 days to determine percent germination.

If you don’t have seed, check a cover crop seed supplier to request some free seeds for testing.

Select Seed to Match Your Need

Know what your goal is for the cover crop in order to determine what to plant.

Do you want to capture the nitrogen already in these fields?

Both legume and non-legume cover crops can capture soil profile nitrogen in their plant tissues for release in subsequent seasons.

Late summer or early fall seeded cover crops favor the brassicas (turnips; oilseed radishes, including Tillage Radishes; and canola) for nitrogen trapping for the next crop.

Oats make a good complement to seed with the brassicas, since the oats provide quick, weed-suppressing biomass while taking up excess soil nutrients.

These plants can survive a light frost and keep on growing.

If reducing compaction is your concern, turnips may help with surface compaction while radishes provide a longer taproot to work through deeper compaction.

If forage is needed for haying or grazing, good choices would be winter annual grasses such as cold-tolerant “winter” oats, cereal rye, winter triticale, and winter wheat.

Winter legumes such as yellow sweetclover and winterpeas also may be included in a mix with winter triticale to increase protein content.

However, these legumes will need to be planted before early September to provide grazing benefits.

Corn and soybean fields also can be used for forage instead of grain.

Silage is probably the best option when the moisture drops to 60 percent.

Currently, the immature hailed corn fields are still about 80 percent moisture, so producers will either have to wait for the crop to dry or mix dry forages such as straw with the wetter silage in the right proportion.

Conversely, if the plants get too dry, it will be hard to pack the silage.

To check the moisture, harvest several stalks and chop into smaller pieces with a corn knife, and then test for moisture content.

Usually, the feeding value of immature, hailed silage is similar to prairie hay based on nutrient content.

Grazing the hailed fields is another option.

However, acidosis may be a concern if cows graze primarily on the immature ears.

Cows should be fed some grain for a few days prior to turn out on the hailed fields to help their rumens adjust to a higher carbohydrate diet.

Haying and earlage also may be options, but forage curing is difficult with the cooler days, especially if ears don’t dry well on damaged stalks.

Bruce Anderson, UNL forage specialist, says that it takes 10-14 days longer to dry the damaged corn stalks after crimping than drying cane hay.

So, the risk for mold potential on the forage is higher than moving the forage into silage. ❖


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The Fence Post Updated Oct 16, 2013 03:58PM Published Aug 29, 2013 09:30AM Copyright 2013 The Fence Post. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.