Drought: Resources & Options for Corn


Well, the heat isn’t letting up.  Sixty-nine Nebraska counties are allowed to hay and graze Conservation Reserve Program (CRP)  lands.  In our area these counties include:  Hamilton, Hall, Webster, Nuckolls, and Thayer.  From Teri Post at the Webster Co. FSA office, this means that:  “If it (CRP) is hayed, it cannot be sold and cost to the livestock person cannot exceed the 10% reduction on contract payment.  Paperwork MUST be completed prior to anything being done.  If you do not have livestock but do have a CRP contract, you can lease your acres to a livestock producer.  They have also released CP25 (wildflower mix) for grazing only.  If you prefer to sell the hay and you qualify for managed haying, you may do that but you will be assessed a 25% payment reduction rather than the 10% with emergency release.  Also keep in mind that use of emergency haying or grazing restarts the time clock for when you can hay or graze next.  If you use the emergency hay or graze release, even if you hayed or grazed in a prior year you are now eligible to hay or graze again.”

Nebraska Farmers who have drought damaged corn which could be swathed and baled, chopped, or grazed can list that on the Nebraska Hay and Forage Hotline.  The hotline is available free of charge for buyers and sellers to list feed resources.  Call the hotline at 1-800-422-6692 to list the forage you have or to list your need for forage.  I’ve been contacted by Extension Dry Panhandle rangelandEducators in the Sandhills asking if we have any producers willing to rent cornstalks for grazing this year to please let me know and we will put you in touch with producers in the Sandhills who need forage.

UNL Extension has developed a Drought Resource Web resource that pertains to crop and livestock producers. Some of you have been asking about options for dryland crops right now.  Research has shown benefits to the following crop if stubble height is left at least 10 inches tall when haying or cutting silage from drought damaged corn fields.  Leaving a higher stubble height will also reduce the nitrate levels in the forage that has been cut. 

When it comes to your options on what to do with weather-damaged corn, Dr. Bruce Anderson, UNL Extension Forage Specialist and Tom Dorn, UNL Extension Educator, recommend to consider the following points before harvesting your crop as forage:

  • If grain prices remain high, grain yield may not need to be very high to justify selecting grain harvest over forage harvest.
  • Sometimes leaving the corn residue can result in increased yield next year and that increase may provide more value than that resulting from forage use. See NebGuide G1846, Harvesting Crop Residues for information on evaluating your situation.
  • Check labels of all chemicals applied to be sure they are cleared for forage use and that the minimum harvest interval has been met.
  • Check with the USDA Farm Service Agency and your crop insurer to maintain compliance with farm programs and crop insurance requirements.
  • Nitrate concentrations can reach toxic levels in weather-damaged corn. The harvest method can affect the nitrate, a particular concern when its being fed to livestock. Leaving a tall stubble (8 or more inches) will reduce nitrate risk but note eliminate it. Choose the harvest method accordingly.

Silage may be the safest method of harvest as fermentation usually (but not always) reduces nitrate levels and risk. Yield is about one ton per acre of silage for each harvested foot of earless corn plant (not counting the tassel). Feeding value is about 70% to 80% of well-eared corn silage. Corn with some grain (less than 50 bushels) tends to produce about one ton of silage for every five bushels of grain with a feed value about 80 to 90% of regular corn silage.

Harvest timing is critical with silage to ensure the correct moisture for proper fermentation. Plants probably are about 80% moisture now and the desired moisture level for silage is about 65%. Plants with any green leaves usually are too wet to chop for silage. For proper moisture, most leaves may need to be dead before chopping. The stalk and ear hold amazingly high water concentrations. For corn with no grain, even if all leaves are dead, the whole plant (and silage) moisture can be 70% if the stalk is still green and alive. Once plants actually die they can rapidly dry down.  There are several ways to reduce moisture content:

  • If corn has pollinated, delay silage harvest until all chances of increased biomass tonnage have passed or plants naturally dry down to appropriate moisture levels.
  • Corn can be windrowed and allowed to partially dry before chopping.
  • Excessively wet material can be blended with drier feeds such as ground hay, cracked grain, or dried distillers grains. However, this can take a lot of material — about 500 lb of grain or hay to reduce each ton of chopped corn with 85% moisture down to 70% moisture.
  • Silage inoculants may improve fermentation and preservation of drought-damaged silage.

Green Chop:  Green chop minimizes waste but may be the most dangerous way to salvage corn. If present, nitrates will start to change into nitrites (about 10 times as deadly) as green chop begins to heat. Chop and immediately feed only an amount that animals will clean up in one feeding. Chop and feed two or three times per day instead of providing excess feed from a single chopping. If any green chop remains two hours after feeding, clean out bunks. Never feed green chop held overnight because nitrites can be exceptionally high. Be sure to allow plenty of bunk space (36 inches per cow is recommended) so boss cows don’t overeat and timid cows can get their share.

Hay:  Hay may be the most difficult method of mechanical harvest, especially if ears have started to form – the stalk and especially the ears will be slow and difficult to dry. If possible, use a crimper when windrowing. Unlike with silage, nitrate levels do not decrease in hay after it is baled. Some of the nitrate risk can be reduced by cutting to leave a tall stubble, about 8 inches. Tall stubble also will elevate the windrow off the ground, allowing air to circulate better through the forage and aid in drying.

Grazing:  Challenges with grazing include acidosis risk for cattle not accustomed to grain if ears have started to fill (smart cows will selectively graze ears), waste from excessive trampling, availability of drinking water, perimeter fencing, and nitrates. Reduce acidosis risk by feeding increasing amounts of grain similar to feedlot step-up rations before turning into standing corn that has much ear development.

Reduce waste by strip-grazing with at least two or three moves per week; daily is best. Back fences are not needed because regrowth is not expected. Water can be hauled in as with winter corn stalks or lanes might be constructed with electric fence to guide animals back to water sites that are nearby. If strip grazing, animals can walk back over previously grazed areas since back fences aren’t needed.

Perimeter fences can be built using the same fencing as for winter stalks. Cows are likely to respect such fencing but inexperienced calves may not remain where desired. To better control calves, use a double strand of electric wire and/or a more visible barrier such as electric polyrope or polytape. Animals not already experienced with electric fences may need some exposure and training before moving them to a corn field.

Nitrates usually are not a problem with grazing since the highest concentration is in the stem base, the plant part least likely to be consumed. Risk increases, though, if animals are forced to “clean-up” a strip before moving to fresh feed and when corn plants are short (probably less than 3 to 4 feet tall) with small, palatable stem bases. Tests for nitrate concentration (whole plant and just the bottom 8 inches of the stem base) can be made prior to grazing to assess risk. If nitrate levels are risky, the hazard can be reduced by offering enough desirable forage to discourage consumption of hazardous plant parts as a major component of diet. Also, delaying grazing until plants more fully mature often lowers nitrate risk.  NebGuide G1865, The Use and Pricing of Drought-Stressed Corn, offers additional information.

Windrow Grazing:  This method includes cutting as you would for hay and then grazing the windrows rather than baling them. It eliminates the cost of baling, transporting bales, feeding bales, and maybe hauling manure. It also eliminates any flexibility in feeding location and may reduce opportunities to sell the corn forage.

Windrowing tends to preserve forage quality better than allowing plants to stand. Usually it is easier to strip graze windrows than standing corn because building fences and estimating strip size are easier. Snow cover rarely causes problems if animals already know the windrows are there. They will use their hooves and face to push snow aside to access the windrow. Thick ice, however, can cause a significant barrier. Follow appropriate management recommendations listed earlier for hay and grazing for best utilization and safety.

Additional Resources: US Drought Monitor Map and High Plains Drought Monitor Map

 

About jenreesources

I'm the Crops and Water Extension Educator for York and Seward counties in Nebraska with a focus in irrigated crop production and plant pathology.

Posted on July 23, 2012, in Crop Updates, Discussion Topics, Drought and tagged , , , , , , , , , , , . Bookmark the permalink. 2 Comments.

  1. Mark Reed Hinze

    Jenny, you use our Social Media unlike anyone else I have ever seen! Amazing Talent! Keep up the good work! Someday, I’m going to grow up to be like you !!

  2. Thanks for the kind compliment, Mark! It’s not difficult to use social media to share UNL Extension’s resources and the information can benefit clientele across the globe. You can easily do this too! Let me know if you have questions and hope your summer is going well!

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