More study needed on grain drying debate

An aeration fan manufacturer is advising farmers to stick with past practices until more research is completed.

Imre Varro of Edwards Group in Alberta, which makes Grain Guard fans, said producers should take note of recent research that calls for intermittent aeration strategies but wait for further research before adopting it on their farms.

“Provincial and state ag departments, universities in Manitoba, Saskatchewan, Minnesota and North Dakota have all looked at this before,” Varro said.

“Farmers have proven the processes we rely on now, and they work. So let’s keep using them until more research is in.”

He said research has shown that the relationship between relative humidity, air and grain temperatures determines the rate at which grain dries.

To assume that air at a certain temperature is at a particular relative humidity is incorrect, he added. These conditions, relative to each other, vary greatly throughout the fall.

“Weather conditions in Western Canada are widely varied from year to year and even through a particular harvest season,” he said.

“There are so many variables that it is wise to look at test results taken over several years, performed under varied weather conditions, at different locations and points in the season and by more than one independent laboratory.”

Controlled conditions are required for the testing to be valuable, he said.

“When a producer starts his fan to natural air-dry, a drying front in the bin begins,” he said.

“This is a band of grain that spreads horizontally through the bin, where the grain is giving off the most moisture (sweating) to the dry air travelling through the grain.”

Varro said 20 years of producer feedback and several studies have shown that once the drying front has started, it is advisable not to stop fans until the front has moved completely through the grain. A few hours of stopping airflow can result in stagnant moisture and kick start the moulding process.

If this happens, grain within the drying front will crust and it becomes difficult, if not impossible, to effectively move air through the grain.

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