With increasing demand for larger capacity on-farm grain silos, farmers need to ensure design and storage management are on-song.
Visiting GSI grain storage expert Randy Sheley said US on-farm silo systems were a decade ahead of Australia.
“On-farm storage has always been something we have had because the marketing system dictates that you might make a little more money if you are able to store it,” he said.
While the industry is now offering silo systems with larger capacities this means bigger storage challenges, Mr Sheley said.
He said systems in the US were focused on aeration and then temperature control and fumigation.
“Typically if we can get grain down to a low level of moisture the insects leave it alone - fumigation is not something you do unless you have a problem - it seems like the opposite here.
“The main course of action we use is to bring the temperature of the grain down, but obviously fumigation eliminates insects and sealed silos improves the effectiveness,” Mr Sheley said.
He said aeration was a key factor but more complex than fitting a fan and adding bigger fans could increase static pressure moving moisture layers around.
“Putting more air in can move the moisture from the silo bottom to the middle layers but there's typically not enough aeration to move it out of the bin,” he said.
“The redeposit of the moisture causes problems and is where a lot of grain bin fires come from.”
He also cautioned that aeration will not condition grain as you require 10 times the airflow volume for conditioning grain as you do for aeration.
Selecting fan systems based only on volume per bushel was also problematic, he said.
“This has been around forever but it doesn't work on really big bins.
“What farmers should be looking at is the velocity of air going through the grain which is something GSI has been working on, “ Mr Sheley said.
Larger diameter, shorter bins are easier to aerate, but smaller and taller is cheaper so you have to balance the two.
So too full aeration floors outweigh partial aeration floors by providing an even air distribution, he said.
Drying systems could offer productivity gains.
“Drying may be a cheaper and more effective than investing in another harvester or being beholden to harvest conditions,” Mr Sheley said.
He said a bin could be a dryer as well as a storage device, however, 18 per cent moisture content wheat would need 17 to 30 litres per second per tonne, to come to acceptable levels and grain depth needed to be kept below seven metres.
Trying to store grain at a wetter level almost never works out, he said.
