8 Tips for Covering Bunkers to Preserve Nutrients

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Quality feed entails several steps. Growers must harvest the nutrients from the field, ensure proper packing density at harvest and manage the bunker through feedout. Covering the bunker is a key step, notes Bill Ramsey, MS, Pioneer livestock information manager. A properly covered bunker can seal out air, which can spark aerobic fermentation, bunker heating and loss of valuable nutrients.

Ramsey cites suggestions from Brian Holmes, University of Wisconsin-Madison, and Professor Emeritus Keith Bolsen, Kansas State University, to minimize or prevent surface-spoiled silage:

  • Two sheets of plastic or one of other protective films are preferred to one sheet of plastic.
  • Overlap sheets that cover forage surfaces by a minimum of 4-6 feet.
  • Arrange plastic sheets so runoff water does not come in contact with silage.
  • Sheets should reach 6 feet off the forage surfaces around the perimeter of a drive-over pile.
  • Put uniform weight on the sheets over the entire surface of a bunker or pile, and double the weight placed on the overlapping sheets. Bias-ply truck sidewall disks, with or without a lacework of holes, are the most common alternative to full-casing tires. Sandbags filled with pea gravel are an effective way to anchor the overlapping sheets, and they provide a heavy, uniform weight at the interface of the sheets and bunker silo wall. A 6- to 12-inch layer of sand/soil or sandbags is an effective way to anchor sheets around the perimeter of piles.
  • Prevent damage to the sheets or film during the entire storage period. Mow the area surrounding a bunker or pile and put up temporary fencing to safeguard against domesticated or wild animals.
  • Regular inspection and repair are recommended because extensive spoilage can develop quickly if air and water penetrate the silage mass.
  • For many years, full-casing discarded tires were the standard method to anchor polyethylene sheets. They’re cumbersome and messy. In addition, standing water in these tires offer a potential breeding ground for mosquitoes that may carry the West Nile virus.


Learn more about proper bunker management at The Silage Zone® on pioneer.com.