Moisture levels in crops at harvest time would often be higher than levels recommended for safe storage.
“In a good year you could harvest wheat or barley at 14% moisture and it would be fine to store without requiring drying,” Pyke said.
“In a year like this it would often have been higher, possibly 16-18%, so it would have to be dried and cooled.”
Maize always needed drying because of its high moisture content at harvest.
For wheat, barley and maize, 14% moisture was ideal for long-term storage.
After drying, the grain and seed would need cooling, down to 15C before it was ready for long-term storage. If the grain was going to be fed straight away, higher moisture levels made it cheaper to produce and did not affect the feed value to cows.
However, when farmers stored grain they often would not know exactly how long it would be in storage for. Growers sometimes delayed harvest, hoping for better conditions and more favourable moisture levels in their crop to save on drying costs.
Pyke said that could backfire if the quality deteriorated in the field while awaiting harvest.
Ideally, the moisture content in your wheat, barley and maize should be at 14% moisture for long-term storage.
The risk of rising temperatures and moisture levels was relatively low during the first three months, but after that storage conditions should be monitored every month or even fortnightly.
“In the first three months probably not much is happening because it’s relatively dry and low in moisture, but after that things can go downhill pretty quickly.”
If moisture and heat was found to be rising, the grain or seed needed to be removed, then dried and cooled again.
If stored in an aerated silo, cool air (such as that on a cool, frosty night) could be pulled through the silo, cooling the grain and removing moisture.
Pyke said sucking air through a silo was not a huge cost, but having to put heat in a system for more drying could add significant cost.
Insect invasions could be managed by post-harvest fumigation, but it was usually an indication that something had not been done particularly well during storage.
Silos and storage facilities needed to be thoroughly cleaned between storage every year and treated so no insects could survive. Insect problems could also be avoided by ensuring there was no grain left in any of the equipment used at harvest.
“Then at storage, if you have the right moisture content and temperature, the problems should be very few and far between,” Pyke said.
“When things go wrong they can go wrong quite markedly.”
