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Planting Cover Crops into Storm-Damaged Fields

A common question lately has been “I’m considering planting cover crops into areas of corn and soybean fields with hail damage.  What are my next steps?”

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

Hail damaged cornIn some areas hail stripped corn and soybean plants to the ground, leaving just stems standing. Cover crops offer an opportunity to rescue nitrogen already in the field to achieve other goals.

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.

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 7-14 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%. Currently, the immature hailed corn fields are still about 80% 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.

Thanks to Todd Whitney, UNL Extension Educator, for his contributions to this article!

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Cover Crops & Fall/Spring Forage Options

With corn being harvested for silage, corn maturing early, and livestock producers looking for forage options, I’ve received questions about seeding cover crops or forage options.  Mike Burgert from the Clay County Natural Resources Conservation Service also wanted me to share the concern of the loss of reside and the increased likelihood of soil erosion.  He said if harvesting crops for forage takes place on a USDA program participant’s “highly erodible” acres, this would likely not be an approved conservation system and could cause ineligibility for USDA programs on all of their land in programs. He also said they have cost share for drought related practices (cover crops for forage on cropland, stock water well/pipe/cross fencing/water facility, etc.).  

Dr. Bruce Anderson shared the following information:  Before planting anything, review your herbicide history. Prior use of contact herbicides like glyphosate won’t cause any problems, but some herbicides have a long soil residual effect that could prevent successful establishment of some crops.  Double crop choice is likely to be different for rainfed and irrigated conditions. One ton (dry weight) of forage production is likely to use 4-5 inches of water. For rainfed conditions, a crop that will winter kill is preferred in order to accumulate soil water from snow melt and spring rainfall for the next crop. For irrigated conditions, forage production will be more with a crop that survives winter and is spring harvested—although irrigation for the forage and following crop will likely need to be increased compared with no double cropping.

Fall Forage options:  Determine when the forage crop is to be harvested and how it will be used. For fall-harvested hay or silage, oats or other spring cereals will outyield all other options. Plant about 100 lb. of seed per acre. Various legumes like hairy vetch, field peas, or winter peas can be added to increase protein concentration a percentage point or two, but they are unlikely to increase dry matter yield; the forage from the cereal alone will meet most cattle protein needs. Also be wary of spending more for the seed than the extra protein might be worth. For grazing this fall and winter, turnips and oats (separately or in a mixture) usually will provide the most feed.
     Early planting and emergence (irrigation or soil moisture must be available immediately) is essential for successful fall forage. Plantings after Labor Day rarely produce sufficient growth for mechanical harvest in the fall and the amount of fall grazing becomes negligible for plantings made after mid-September. Even earlier planting dates may be needed for sites north of the Platte River. Later plantings should consist of winter cereals. Also, the chances for successful establishment are low unless soil is sufficiently moist to at least an eight-inch depth at time of planting.

Spring Forage Options:  For spring forage, the winter cereals rye, triticale, and wheat tend to be the best choices. Rye is your best choice for early spring pasture and produces much growth before being terminated for timely planting of a row crop. Some rye varieties also provide enough fall growth for some light grazing if planted early enough. Rye also may be the most reliable crop when planted under stressful conditions. Rye has some drawbacks. It turns stemmy and matures much earlier than triticale or wheat, with a loss in feed value and palatability, although this should not be an issue if harvest ends in time for spring planting of a row crop. Also, it should not be used in fields that will be used to grow grain wheat due to potential contamination that could lead to discounts/dockage when wheat grain is sold.
     Triticale holds on to its feed value best into late spring. This makes it well suited for hay and silage, or for stretching grazing well into June if grazing begins two or three weeks later than it could begin with rye. Triticale often is more susceptible to winter injury than rye and wheat.
     Winter wheat will provide very little grazing for fall. During spring, forage quality and acceptance is very high but forage yield is less than rye and triticale. It can be grazed and then allowed to produce grain if grazing ends when plants begin to joint and elongate.
     Mixtures often can be desirable and can be designed for individual needs. For example, an early planting of 30 lb. of oats plus 75 lb. of winter rye per acre may provide both fall grazing from the oats and spring grazing from the rye. 

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