|Holmes, Brian -|
Submitted to: Progressive Forage Grower
Publication Type: Popular Publication
Publication Acceptance Date: February 7, 2014
Publication Date: March 1, 2014
Citation: Muck, R.E., Holmes, B.J. 2014. What's new and basic in making good silage? Progressive Forage Grower. 15(3):35-36. Technical Abstract: The biggest and most variable losses from silage during storage and feed out are caused by spoilage microorganisms. Spoilage microorganisms need oxygen. So, the keys to low silage losses are to: 1) pack to a high density, 2) seal the crop in storage with a good quality plastic film that is held tightly to the crop surface, and 3) feed out at a high rate from the face. Today there are some new options to achieving a high density and sealing bunker or pile silos. A number of devices that attach to a packing tractor have come on the market to improve silage density. We tested a 10,000 lbs. device, an impact silage packer that attaches to the 3-point hitch on the packing tractor, on several bunker silos being filled to make corn silage. The impact silage packer worked best when the 3-point hitch allowed the packer to fully exert its weight while riding on the forage. In our trial, it provided modest improvements in density. There are two critical components to eliminating top surface spoilage: the quality of the plastic film and how well it is held against the crop. The most common plastic film is polyethylene, white or black, of varying thicknesses, typically 5 to 8 mil. What we found comparing different types of polyethylene is that color has little effect on losses but thickness does. Today, there are a number of oxygen barrier films on the market, which use a reduced oxygen permeability plastic, alone or in combination with layers of polyethylene. In our trials, low dry matter losses, normally less than 5%, have been measured in the top 6 in. under these films. Quality of film is not the full answer to preventing spoiled silage at the top of bunkers or piles. If any film is billowing in the wind, it can act like a bellows drawing in air around the edges of the sheet and permitting spoilage. To prevent this, the standard tires-touching-tires keeps the plastic in place. Today a number of tarps (woven or expanded mesh) secured with gravel bags are available that can do a similar job. The final issue of sealing is at the edges of sheets. This is a particular problem at the walls in bunker silos. Placing plastic down the side walls prior to filling and lapping those sheets onto the top prior to putting the down top sheet can minimize spoilage at the wall. The bottom line is to buy a quality plastic film to minimize oxygen passing through the film and secure it well to minimize oxygen entering under the edges of the sheets.