Silage storage guidelines

Introduction

Although many high-quality crops are harvested efficiently, there can be significant losses of DM and quality if the silage storage system is inadequate. These losses are due to excessive respiration (overheating), effluent loss and aerobic spoilage in the stack or bales.

They can be minimised by good management during filling and storage. There is a range of storage systems used for preserving silage. These include underand above-ground systems, with the capacity for handling both chopped and baled forage.

All systems are capable of producing highquality silage. However, above-ground storage that relies on a plastic cover for protection is usually only suitable for short-term storage.

Storage time may be increased by providing a second protective cover over the silage plastic, to reduce breakdown by sunlight (ultra-violet radiation).

As long as there is no physical damage to the plastic, this may extend the storage time by 3-5 years. The system chosen for a particular enterprise will depend on the purpose for which the silage is being used, available equipment, expertise and personal preference.

When choosing a storage system it is also necessary to consider how the silage is to be fed out. Poor planning of the feedout phase through inappropriate design or location of the storage facility, or an inadequate feedout system, can result in an expensive silage system.

Safety first

Whether storing silage in pits, bunkers or bales, take all necessary precautions to avoid injury when using heavy machinery. Safety issues should not be ignored.

Ensure all operators read and fully understand any information provided by the manufacturer on the machinery’s safe operation.

• When preparing pits or bunkers, excavation is a safety issue. Check the guidelines that apply in your State. In NSW, for example, the NSW Code of Practice: Excavation 2000 provides legal guidelines and responsibilities for persons engaged in excavation work.
• It is available from the Workcover Authority of NSW or from its website www.workcover.nsw.gov.au
• Guidance notes on Hay and Silage Bales and Trenching Codes of Practice are available from www.workcover.vic.gov.au and Codes of Practice for Transport of Silage and Hay from the Australian Fodder Industry Association (AFIA) website www.afia.org.com.au
• Seek help from Workcover, or the relevant State authority, to ensure all equipment and practices are safe and satisfy recommended guidelines and regulations.

The Key Issues

Successful storage depends on:

1. Producing an airtight storage unit as quickly as possible after completion of harvesting.

2. Maintaining an airtight seal until feeding commences.

Chopped (forage-harvested) silage

• Ensure harvested forage is at correct DM content for length of chop used.
• Spread harvested forage evenly (to a depth of about 15-30 cm) before rolling.
• Continually roll the forage during harvesting, and ensure forage is well compacted to expel as much air as possible.
• Long, narrow, deep stacks are more effective than short, wide, shallow stacks.
• Until harvest is complete, cover the stack at night, weighting the plastic along the perimeter.
• When harvesting is completed seal the stack as soon as possible after adequate compaction.
• Bury the edges of the plastic in the ground to ensure an airtight seal. This is more effective than simply covering the plastic with soil.
• Regularly inspect the stack for holes during storage. Repair holes as soon as noticed using tape specifically made for silage plastic.

Baled silage

• Bale at the correct DM content.
• Bales should be well compacted (of high density) to minimise air pockets.
• Ensure the storage site is clear, control weeds, rodents and remove objects that may pierce the plastic. Do not store under trees or too close to fence lines.
• Seal the bales with plastic as soon as possible after baling.
• If possible, seal the bales at the storage site rather than in the paddock where they are baled.
• If wrapped bales must be moved, use handling equipment that will not damage the plastic.
• Regularly inspect bales for holes during storage. Repair holes with tapes specifically made for stretchwrap plastic as soon as they are noticed.