Compaction and sealing

Plant enzymes and naturally occurring aerobic (oxygen-loving) bacteria convert plant sugars and proteins into water, carbon dioxide and heat. This results in a loss in both quality and quantity of pasture to ensile.

Good silage compaction and sealing will help ensure an efficient fermentation process and reduce the risk of heating and mould growth.

Compaction targets for stacks and bunkers are shown in Table 3:

Wet silage (kg)

Table 3: Required densities for stacks and bunkers6
   Compaction density (kg/m3
Drymatter percentage of pasture silage (%) Drymatter (kgDM) Wet silage (kg) 
720 180
30 670 200
35 630 
40 600 240

Stacks or bunkers

  • Spread grass into 100 - 150 mm layers and compact until the surface is firm.
  • Seal the stack using a high quality plastic cover and weigh it down with tyres that are touching.
  • Seal the edges with sand or lime.

For bales

  • Use a reputable baling contractor with well maintained machinery.
  • Wrap bales as soon as possible after making silage.
  • Use quality plastic and follow the manufacturer's recommendation for the number of wraps.
  • Handle bales carefully to avoid puncturing the wrap.
  • Stack bales no more than two high.

6Honig, H. 1991. Reducing losses during storage and unloading of silage. Forage toward 2000, FAL 1991, p. 116-128.