The grain bag was developed to store dry grain for short periods.
However, that type of use means the $60,000 price tag for bagging equipment doesn’t make economic sense, says Digvir Jayas, a grain storage researcher with the University of Manitoba.
To make it make sense, Jayas added, many farmers end up committing production errors.
“You’re not going to buy the machines just to have them on hand in case you need to fill a couple bags for three months if you have a bumper crop,” Jayas said.
Read Also
Sask. ag group wants strychnine back
The Agricultural Producers Association of Saskatchewan has written to the federal government asking for emergency use of strychnine to control gophers
“Farmers have invested heavily in the machinery. To justify that expenditure, they want to switch their primary grain storage over to the bag system, but it’s not designed for that purpose.”
He said producers are bagging grain that’s far too wet and they’re keeping it in for too long. The obvious result is grain that heats and spoils.
“The problem is that we have no systematic studies done in Canada to tell us what will work and what won’t work. Farmers desperately need such information.”
In his 25 years researching grain storage, Jayas said he has found only one study from Australia and two from Argentina dealing with grain bag storage. A corn study in the United States was started but not completed.
Jayas recently proposed a two year research project in conjunction with the Canola Council of Canada and the Canadian Wheat Board. The study would deal with dry canola, wet canola and cereals. If funding becomes available, the study will result in the first set of recommendations based on Canadian prairie conditions.
For now, however, producers must rely on the foreign studies. One of them is from Argentina and is what George Adair of Adair Sales and Marketing in Swift Current, Sask., gives producers when they ask about grain bagging.
He and Jayas agree the information seems valid.
However, it should be used not as recommendations but as a basis for questions farmers should consider if they want to bag grain.
According to the study, the idea behind bagging grain is to keep it dry with low oxygen content and a high concentration of carbon dioxide. This modified atmosphere reduces the biological activity of insects, fungi, seeds and grain within the bag.
Biological activity is the major cause of heat in stored grain.
The study says that grain is a living organism and should be whole, clean and devoid of mechanical damage to have a greater chance of maintaining its quality during storage.
Bags should be located on high ground with good drainage. The surface should be level and smooth with no stones or sharp objects. If necessary, the ground should be graded and graveled. A firm base also helps when emptying the bag.
Positioning bags in a north-south orientation minimizes exposure to solar radiation.
Argentine researchers installed an 80 percent sun-blocking mesh as a protective tent about 40 centimetres above bags in the spring and summer months. This blocked the direct sunlight, resulting in lower temperatures inside the bag and reduced the risk of damage.
Bag quality is fundamental. It must be able to remain stretched over a prolonged time without losing its watertight and grain-conserving capabilities.
It is important to properly stretch the plastic, which partly depends on keeping up a steady filling rhythm. Regulating the braking action is essential and requires an efficient brake assembly and good terrain preparation.
Pressure exerted on the bag while it is filled is produced mainly by the weight of each grain kernel and to a lesser extent the machine’s auger, the study said.
The grain gradually pushes against the bag walls as the compression auger moves it forward into the bag . The bag resists this pressure.
The operator can attain the appropriate balance of pressure and tension by properly regulating the brake action.
The auger screws are an important consideration. They should be centered, be of the greatest diameter possible and have a smooth finish with no sharp edges. They run at low r.p.m. and should be set in a horizontal position or at the lowest possible angle.
The auger should never be operated when it is not completely full of grain. Worn augers should be replaced because they cause significant mechanical damage to grain.
According to the study, all these factors must come together for the bag to have the right proportions and a uniform diameter along the entire length. The greatest possible amount of air must be expelled while the bag is being filled.
The bag should not be loose or exceed the stretching limit recommended by the bag manufacturer. The degree of stretch is gauged by monitoring the length of the bars printed at regular intervals on the side of the bag.
In Argentina, the general rule is that the moisture level at which grain is bagged should not be higher than the base moisture standard for commercial purposes.
Low-moisture grain maintains better quality over a longer time. As moisture levels increase, so too does the risk of damage. Damp grain should be bagged only when there is no alternative.
The report concludes that although grain bagging is a simple technology, extreme care must be exercised in protecting and maintaining the integrity of the bag.
Continuous monitoring is necessary so that ruptures can be repaired immediately, preventing air, water, insects, disease and rodents from entering the bag.
When evaluating risk, producers must consider the moisture content of the grain at the time of bagging, the aging process of the bag and the possibility of external damage.
The risk increases as the ambient temperature rises and when there is foreign matter, impurities and mechanical damage to the grain.
Grain that is damp, damaged and has the most foreign impurities should be sold first.
