Assessing pros and cons of silo storage
From the October 2007 edition of Agriculture Today.
There are a variety of options for storing silage, according to NSW Department of Primary Industries (DPI) agronomist at Cootamundra, Phil Bowden, who has looked at the pros and cons of the different methods.
"Storage silos should be in a convenient location to minimise travel for harvesting and feed out and where they can be monitored for damage," Mr Bowden said.
"A well drained site with all weather access will help with the feed out in winter and avoid contamination of the silage with soil or mud.
Chopped silage can be made on site and there are four storage options: underground or hillside pits, above ground bunkers or stacks.
Stacks or ‘buns’ are a shortterm option with a storage life of two to three years.
Forage is dumped on the ground, rolled and sealed with plastic sheeting, then weighed down with tyres.
"Advantages to this method are no construction costs and adaptability for feeding out," Mr Bowden said.
"However, there are greater losses due to a large surface area, and compacting the stack can be difficult and dangerous."
Above ground bunkers are walled structures into which the chopped forage is dumped and rolled.
Covered in plastic and then weighed down, they are short to medium-term options.
Underground pits can be dug, usually as a permanent fixture on the farm, in a well drained area with good access.
Usually they are covered with plastic and topsoil so they shed water.
"These are relatively inexpensive to construct for long-term storage, but can be difficult to access during wet weather," Mr Bowden said.
Baled silage can be as individual wrapped bales, in underground pits or plastic covered stacks.
"The disadvantages of wrapped bales are that the product is only for short-term storage (12 months), is high cost per tonne, and is easily damaged by vermin and handling," Mr Bowden said.
Plan to use this silage to fill feed gaps in the year after it was made, he said.
Bales can be stored in underground pits as well, usually with a plastic cover and a layer of soil or tyres to seal it. This is best done with square bales.
"Disadvantages here are that there will be some losses when opening the silo and feeding out gradually from the pit," Mr Bowden said.
"This can be minimised by sealing separate compartments of feed within the pit.
"Above ground stacks of baled silage can also be done successfully, but this is a short-term method and it is best to be used within two years of ensiling." Mr Bowden said
NSW DPI would have TopFodder days on across the region and these field days were the best way of learning how to use silage.
Contact Phil Bowden, Cootamundra, (02) 6942 4957
