Grain bags need study
Grain bags seem to be an attractive if fairly new idea on some farms. Yet very little is known about their impact on grain quality when they’re used for longer than four months, says Digvir Jayas, University of Manitoba vice president of research in Winnipeg.
A pioneer in grain storage research, Jayas has studied solid structures other than bags for over the past 30 years. He plans to start a three-year program in late 2010 to monitor seed germination, moisture content, visible molds, free fatty acid values, CO2 and O2 levels in canola, and wheat stored in full-size grain bags in western Canada. He predicts there will be a big difference in storage dynamics.
“In a large bin, about 6 inches of the grain is affected by temperature variation. Bag diameter is so small and the bag is so long, it means a very large amount of grain is going through that cycle of daily temperature change,” Jayas says. “We don’t know, but that variation may have an effect on germination, for example.”
If producers follow the instructions properly, storing dry grain for a short period shouldn’t pose any problems. But because grain bags originated in Argentina under mild conditions, using them in harsher climates could pose challenges.
“For us, moisture migration complicates the issue. I don’t know how the pattern would develop, but some would be near the surface because of our cooler temperatures,” he says.
One of the new Loftness grain bag systems arrived in time for the 2009 harvest at Shaun Moran’s southern Manitoba farm. Moran did save money and time; he also hit a learning curve.
“It was a big crop. The idea was, we’d get some bins empty, then pick up the bags and move the grain into permanent storage,” Moran says. “The ones we cleaned up before spring worked great.”
Two Issues Develop
In spring, a few were still full. Two issues developed. The minor issue was soft, wet soil that delayed unloading.
The more serious issue was that wildlife, probably deer, punctured a few bags. Snow, rain, or both got inside and couldn’t drain. Below one larger hole, the nearby grain began to swell and sprout. Along with it came mold, forming the material into a crusty mass. Due to the new moisture, weight also increased.
The unloading procedure uses a shielded cross-auger that fits inside the bag, across its base. Normally, grain flows into the auger, and a roller picks up the plastic, similar to the way a window shade winds up. But in a bad section near the end of one bag, crusty molded wheat broke apart into large chunks that blocked the cross auger. The crew shoveled out some, then watched the bag stretch and tear from excess weight as they attempted to continue rolling it up. They eventually cut off the end and got a fresh start.