STORING BORDERLINE MATURITY CORN

By Helmut Spieser, OMAF; Ridgetown

The 2003 crop year has been interesting to say the least. It was a cold, wet or backward spring depending on where you farm. This resulted in corn that either sat in the ground for a couple of weeks or ended up being planted later than normal. Late July was dry and cool; August had hot spells then frost came earlier than expected in late September. All this combined with marginal heat; poor stalk strength, tall corn, big cobs and high winds resulted in some very tangled corn fields at harvest. The bottom line is that not all the corn may have reached physiological maturity. You should watch this corn more carefully in storage than you normally would.

Fragile Kernels
Any handling of immature corn will result in the production of fines. Corn kernels that are not psychologically mature are not as structurally sound as mature kernels. Try to minimize the amount of handling of this immature corn to eliminate the production of fines as much as possible.

Problems Caused by Fines
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 tend to be in the centre of the bin. Excess fines will result in airflow restrictions in the storage bin. 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. Since molds grow faster on broken kernels, cleaning the grain will remove broken kernels and reduce the chance of mold problems in storage.

Corn into Storage
The following five items are sound management choices that should reduce the chance for surprises in storage of your dry corn. If you had corn with marginal maturity levels and you did not do all of the following, you need to be extra cautious of your corn in storage. This is not the year for you to check your corn every two months. Visit your bins at least monthly.

• dry corn to one point lower than normal for safe storage
• screen fines from the corn going into the bin
• core the bin after filling
• cool the corn to below 2°C as quickly as possible
• aerate the bin more frequently than normal

Aeration in Storage

• 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
• Hours required for Fall Cooling =15 divided by the CFM per Bushel
• Hours required for Winter Maintenance = 20 divided by the CFM per Bushel

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:
1. Turn on the fan. Check for off-odours.
2. Look for moisture on the underside of the roof. This is a sign of air movement in the bin.
3. Visually inspect the grain.
4. Check the static pressure of the aeration fan while operating. An increase in static pressure indicates that something has changed in the grain mass.
5. Check the moisture content of the corn.
6. Check the temperature of the air coming through the corn. It should be close to the actual corn temperature.
7. Keep records.
8. Mark your calendar for the next bin inspection.

Problems can arise quickly in storage bins when immature corn is concerned. Do not forget to check your bins frequently.