Plan ahead

Ideally, maize silage harvest management starts many weeks before the forage harvester reaches your paddock. It is important to ensure you have a reliable contractor booked, the bunker or stack is ready for the crop, silage making supplies are on hand and there is adequate access from the crop to where it will be stored.



Book in your harvest contractor as soon as the crop is in the ground. Choose a reputable contracting business that has well maintained equipment. Make sure your contractor can vary chop length, plant processor settings and can apply Pioneer® brand inoculant at harvest time. Keep in touch with your contractor as your crop nears harvest maturity.

Bunkers or stacks

If you are using an existing bunker or stack, plan to carry out any necessary maintenance (e.g. drainage) prior to harvest. Remove the residues of last year's silage and where necessary recut dirt walls to give a straight, clean edge.

If you are building a new bunker or stack ensure that it is large enough to hold your crop and that the size of the face matches the rate of feed-out. Aim to feed across the face of the stack every three days taking at least half a metre from the face. To ensure good feed-out management and operator safety, the top of the face should be easily reached from ground level using the feed-out machinery that is available. For good compaction the bunker or stack must be at least twice the width of the vehicle that will be used to compact it.

Build your bunker or stack on a firm base away from hedges, trees and major drains. Choose a site that you will have access to all year round.

Feed-out costs will be reduced if the bunker or stack is built close to where the silage will be fed out.

Maize silage storage requirements

New Zealand research has shown that the average density of a maize silage stack (no walls) is approximately 200 kgDM per cubic metre. The average density of a maize silage bunker (with walls) is approximately 225 kgDM per cubic metre. Overseas research has shown that the target drymatter density for both stacks and bunkers is 250 kgDM per cubic metre. Table 1 gives an approximate guide to the amount of stack or bunker space required in cubic metres.

Cubic metres = length (in metres) x width (in metres) x height (in metres)

Table 1: Approximate stack or bunker space required to store maize silage.
  Approximate storage space required (cubic metres) 
Amount of maize silage (tDM) Stack (no walls) Bunker (with walls)
50 250  222
100 500 444
150 750 667
200 1000 889
250 1250 1111
300 1500 1333