8 Tips for Covering Bunkers to Preserve Nutrients

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.