Staying on Top of Your Stored Corn
By Helmut Spieser, OMAF Ridgetown
Damage due to harvest, drying and handling
of the 2003 corn crop has resulted in an unusually high percentage of fines
in portions of the crop. Fines in storage cause problems every year, not just
this year. Grain spreaders do not ensure uniform distribution of fines across
the whole bin. The highest concentration of fines tends to be in the centre
of the bin. Excess fines will result in airflow restrictions in the corn. Air
will go around pockets of fines and follow the easier route through the grain.
This may result is spoilage of these pockets of fines. Stored-grain insects
are less likely to be a problem if the fines are removed prior to storage. Insects
like Indian Meal Moths and some others, feed on broken kernels. Moulds grow
faster on broken kernels. Some concerns persist about the integrity of stored
corn this season.
- expect storage life to be about 50% of
normal corn
- while aeration equalizes uneven kernel
moisture, broken kernels and pieces of cob increase storage problems
- even if corn went into the bin "dry",
there is still potential for problems to occur
- monitor and aerate bins frequently, more
often than normal.
Aerate your bins thoroughly to ensure
that the whole grain mass is at the same temperature. The grain mass temperature
should be within 5°C of the average outside air temperature. Any more temperature
spread than this can result in uncontrolled convective air movement in the corn
mass that can result in spoilage.
Things to check in the bin:
- Turn on the fan. Check for off-odours.
- Look for moisture on the underside of the roof. This is a sign of air movement in the bin.
- Visually inspect the grain.
- Check the static pressure of the aeration fan while operating.
An increase in static pressure indicates that something has changed in the grain
mass.
- Check the moisture content of the corn.
- Check the temperature of the air coming through the corn. It should be close to the actual corn temperature.
If you suspect problems:
- Moisture under the roof means there
is moisture coming from the corn and you need to aerate your bin.
- Exit air temperature is warmer than the actual corn temperature means the corn was not
cooled throughout. Aerate to cool the whole bin.
- Pull some corn from every bin and check its quality. Use corn routinely from all your corn
storage bins.
- A bin of corn with off-odours should be moved or turned. Turning a bin is
just moving the contents of one bin into another bin. When done in cold weather,
this breaks up pockets of fines and cools the grain.
- Watch your bins much
more closely than you normally do. Corn that is not top quality will go out
of condition within weeks as opposed to months.
Airflow Rate
CFM/Bushel |
Winter Cooling
Hours |
1/10 |
200 |
1/5 |
100 |
1/4 |
80 |
1/2 |
40 |
1 |
20 |
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