Bulk storage for silage means minimal waste, high compaction and labour savings. Campbell Contracting has the only one in Taranaki

Storing your silage crop in a bag is one of the most efficient ways of achieving high quality silage. Silage bagging is becoming increasingly popular in New Zealand due to excellent and consistent quality of the end product. The system has been around for many years, particularly in North America and Europe. By storing your silage in a bag you are able to achieve the following benefits.


+Efficient Harvesting

When harvesting, the machine is packing your silage crop and covering it at the same time. It reduces harvest losses to a minimum because of the way the bagger works, compaction is always consistent and not relying on the competency of the stack operator.

+Compacting the Crop

Crops such as high DM maize or wholecrop cereal are compacted a lot easier, due to constant rotor pressure resulting in a higher quality and more consistent product.

+Small Stack Feed out Surface Area

Your average feed out face is only a fraction of a bunker or conventional silage stack, minimising stack face losses at feed out.


Bags can be placed in different areas of the farm depending on individual requirements.


Because the bag is a set diameter, bag volumes can be easily calculated, should a farmer or grower wish to sell the silage, i.e. 3 x 75 metre bag holds approximately 300 tonnes of silage.

+Minimal Stack Face Losses

When compared to standard silage pits, the plastic cover is a consistent pressure right around the bag with no spoilage issues at the sides and a smaller face which reduces energy and quality loss

+Labour Saving

When the last truck has finished unloading, there is no requirement to have the whole team to cover the stack as the job is done! (NO TYRES NEEDED)

+Higher Quality Feed

Resulting in better animal performance and increased milk production.


After harvest the bag is fully sealed, minimising any potential for silage leachate


  • No tyres to take off stack
  • No cover to roll back
  • Markings on bag for feed calculations
  • Feed out all the silage that you ensile
  • The feed out wagon is closer to the stack
  • No stack face spoilage
  • No mouldy areas to remove
  • All silage has consistent compaction to achieve the best possible quality.

The bagged silage pressing machines compact silage in a unique way that results in the highest quality bulk silage.

The bulks trucks or trailers back into the bagger and tip their load into the unloading conveyer, then the conveyer shifts the load through a set of teething beaters that spread the crop out evenly into a consistent layer ready for compacting. The forage then falls down into the pressing rotor and is forced into the bag by large pressing fingers, similar to the feed rotor on a baler. The pressing rotor keeps filling the bag until the bag has reached the desired compaction, this is controlled by the compaction markings on the bag. As the bag reaches it desired compaction level, the pressure pushes the bagger and tractor along, leaving the bagged forage behind. At the end of the bag the last remaining silage in the bagger tunnel is hydraulically pushed into the bag and the bag is sealed off by placing tyres on the end or simply covering the end with some soil.

The main difference with a bagger compared with conventional stacked silage is that the forage is being compacted and covered at the same time; there is no pumping from the stack tractor as it rolls the stack. While this action is needed, it means that the forage is having the air pushed out of it and as the tractor moves off, it sucks the air back in. Stacks can stay uncovered for many hours while the stack is being made; with the bag it is sealed on the go and the fermentation process can start straight away.

  • Bag lengths: Can vary from 30 to 75 metres and are made from a very heavy duty 230 micron plastic.
  • Bag diameter: Depends on the machine size, with 3 metre diameter being the most common with the larger machines going up to 3.6 metres. A 75 metre long bag, 3 metre diameter holds around 300 wet tonne of silage.
  • Bag storage area required: Total area needed for storage using 3 metre diameter bags is 1 square metre per wet tonne of silage. This figure allows for the total area needed, i.e. includes working areas at each end and allows for a gap between the bags.


Bagged silage comes with a slightly higher “on the day cost,” HOWEVER this is quickly made up through the following:

  • Extra feed conserved and not wasted, due to less spoilage of silage.
  • All silage being fed to the stock is of top quality, minimising the risk of feeding ‘spoiled’ silage to the animal, which in turn can have a negative impact on animal health
  • Ensuring losses are reduced considerably due to the crop being compacted and sealed immediately after being unloaded from the truck.

ag bag stats

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