Tips for buying an EOFY silo

Queensland Department of Agriculture and Fisheries senior development agronomist Philip Burrill said silos are a serious investment and one that is destined to be in use for 25 years or more, so growers should check out the information available from the Grains Research and Development Corporation (GRDC).

“The GRDC has an excellent grain storage website (www.storedgrain.com.au) which provides useful buying guides, as well as management information,” he said.

“A good starting point is to look for a manufacturer that can guarantee their silo will meet the Australian Standard AS2628. The GRDC extension team, researchers and industry worked for many years to establish this silo sealing standard. It ensures growers are able to identify new silos designed and built to a quality standard to enable effective fumigations when required.

“This is absolutely crucial as it allows growers to store grain for long periods, confident that when storage pests are detected grain can be fumigated.”

When fumigation gases like phosphine, or controlled atmospheres (carbon dioxide, nitrogen) are used to kill pests, the storage being treated must be able to hold a given concentration of gas for a specified length of time. 

“In unsealed structures the fumigation gas is lost rapidly, resulting in poor pest control. At best, some adult insects may be killed, but resistant adults, most of the pupae and egg stages survive. This allows the infestation to continue with more adult weevils and beetles emerging,” Mr Burrill said.

“I also recommended you look for a silo that is easy to clean once it is empty. Look at the internal design, such as walls, aeration ducting and perforated flooring. Is it going to trap grain residues?  Insect pests will live and breed in residues left in silos. This allows newly harvested, clean grain to be rapidly infested. 

“Discuss aeration cooling with the silo manufacturer. Consider seeking specialist aeration fan advice to ensure appropriate fans are fitted, capable of delivering 2 - 4 litres of air per second per tonne. 

“Aim to achieve effective grain cooling on the full range of grain types you store.  Ensure internal fan ducting provides an even air distribution and roof venting does not inhibit fan performance.”

While aeration cooling won’t reduce grain moisture significantly, it will provide uniform moisture conditions in the grain bulk, prevent moisture migration and lower grain temperatures. By providing cool, uniform conditions throughout the storage, growers will reduce pest problems, mould growth and help maintaining grain quality. Aeration can also be used for ventilation after fumigation.

“Work health and safety is another consideration. Some silos come without ladders, but this creates issues as it is important to have safe access to the top of sealable silos to conduct maintenance to rubber seals on silo lids and vents.  

“The top of a silo is also a key inspection point for checking on both grain quality and for the presence of storage pests. Mould or insect infestation can often be found at the top of the silo, before it can be detected at the bottom,” Mr Burrill said.

“I would advise looking for silos with a compliant ladder, remembering that ease in safely monitoring stored grain is very important.”

Mr Burrill said regular monthly monitoring of stored grain protects its quality. Problems can be detected early and managed in a timely manner.

Monitoring a cone based silo usually includes sampling grain from the base to sieve for insects, plus inspecting an insect probe trap in the top of the silo. For grain sheds and on ground pads, spearing grain to obtain a sample for sieving and using probe traps is effective. While sampling grain, visual and smell checks are helpful to detect any signs of quality issues developing.

Keeping a simple monthly storage inspection record to record what pests are found, in which storages plus details of any grain treatments or fumigations undertaken is very important. The same record spread sheet may also include the grain variety, quality specifications and tonnage estimates.

“Growers who maintain their reputation as a reliable supplier of quality grain, are able to build a positive, profitable relationship with the grain buyers they choose to deal with.

“Last minute surprises of pest issues in silos, or regular load rejections from grain buyers at the delivery point is clearly worth avoiding,” he said.

Think carefully about your long term future grain segregation needs. Do you purchase four large capacity flat bottom silos, or do you buy two large capacity silos and a number of medium size cone based silos?

“Growers are well aware of the importance of testing for grain quality attributes at harvest time. Grain moisture content, protein, screening and others parameters tested to allow for the best storage segregation choices to be made. This achieves optimum dollar value for segregations and allows for the option to blend when appropriate”. 

Mr Burrill said there are many benefits to on-farm grain storage, but buying a cheap inferior silo is going to cause more problems than it is worth over the long term.

“Storing grain on farm gives you flexibility and harvest time logistics benefits, but it only works if every effort is made to ensure quality is maintained, and the first stop there is investing in a quality silo.”