Research shows that lining the sidewalls of a bunker, in addition to covering the bunker with plastic and gravel bags or tires, helps prevent rain infiltration into the silage. This, in turn, helps prevent dry matter loss due to spoilage. If you want to try the technique this silage season, here’s what you’ll need to do.
Step 1. Line both sidewalls of the bunker with plastic.
Lay one end of the plastic covering on the bunker floor along the length of the sidewall. Take the other end of the plastic and pull it up and over the wall. As you do this, make sure to leave about 1 to 2 feet of plastic lying on the floor along the inside of the wall. Lay sand- or gravel-filled bags at even intervals along the floor to hold the plastic in place. As you pull the plastic over the top of the wall, leave several feet hanging over the outside of the wall. Lay sand- or gravel-filled bags at even intervals along the top of the wall.
Do this step for each sidewall.
Step 2. Fill and pack the bunker with silage just as you would normally do at harvest.
Step 3. Drape the plastic over the silage pile.
Once you have filled the bunker, grasp the plastic that is hanging over the outside of the sidewall and pull it up and onto the silage. Secure the plastic with sand- or gravel-filled bags or split tires. Do this step for each sidewall.
Step 4. Add the top plastic sheet and tires.
Proceed to cover the silage with additional plastic or tarps. Again, either oxygen-barrier plastic or regular polyethylene plastic will work. Place gravel-filled bags or split tires on top of the plastic. Make sure the tires touch to exclude as much air as possible.
This technique will require additional materials, time and labor during harvest season. However, it can help you avoid costly spoilage and dry matter losses from water that seeps into the silage at the sidewalls.