How to minimize top layer spoiled silage in bunker silos and drive-over piles

Monday 27 November 2017

1. Achieve a target density of 650 kg fresh weight (220 kg DM)/m3 in the top 0.75 to 1.0 metre.

2. Shape the top surface convex so water drains off the bunker or pile; and the back, front, and sides of piles should not be steeper than a 1 in 3 slope.

3. Apply the covering materials immediately after filling is completed.

4. A layer of OB film and a sheet of white on black PE plastic or anti UV cover are more effective at preventing surface spoilage than single or double sheets of conventional PE plastic.

5. Overlap the sheets by a minimum of 1.0 to 1.5 metres.  If overlap is less than 1 metre, use Silostop Silotape (Section 6) to ensure joins are airtight.

6. Arrange overlapping sheets so runoff water does not come into contact with the silage.

7. Sheets should reach 1.0 to 1.5 metres from the forage surface around the perimeter of drive-over piles.

8. Put an anti-UV cover or protective woven polypropylene netting (tarp) on the sheet(s).

9. Put uniform weight on all covering materials over the entire outer surface and double or triple the weight where sheets overlap. 

  • Bags filled with pea gravel are an effective way to anchor the overlapping sheets. Placed end to end they provide a heavy, uniform weight at the interface of the sheets and wall of a bunker silo.
  • Gravel bags can be placed on pallets and lifted easily to the top of a bunker silo wall when the forage surface is being covered.
  • Mats can be used as alternatives to gravel bags to give more complete coverage of the top surface

10. A 15 to 30 cm layer of sand and/or soil or gravel bags placed end to end is an effective way to anchor sheets around the perimeter of drive-over piles.

11. Mow the area surrounding a bunker or pile and put up temporary fencing to protect against domesticated and wild animals.

12. Store weighting materials so they do not harbour vermin.

13. Inspect and repair covers frequently to minimise spoilage due to physical damage.

14. Surface spoilage has a negative effect on silage intake and digestibility, and should be discarded.