Harvesting frosted corn for silage a good option

Oct 2, 2009
by WLJ
Harvesting frosted corn for silage a good option

The favorable corn-growing weather in August and September has offset some of the corn crop’s delayed development resulting from the combination of tough spring planting conditions and a cool June and July.

As producers begin to ensile corn, they need to remember that typical corn hybrids for silage require a longer growing period (95 days), says J.W. Schroeder, North Dakota State University Extension Service dairy specialist.

However, corn grain producers who opted for corn with a maturity longer than 85 days increasingly face the possibility that these fields may not achieve the desired maturity before running out of heat units. As a result, crops intended for shelled corn still will be in the field and well above 70 percent moisture or well below 30 percent dry matter, or maturity, when the first frost occurs.

“Autumn has arrived and with each passing day, Mother Nature is in control,” Schroeder says. “Depending on your corn situation, now is the time to consider the likelihood that some fields will not receive enough growing-degree days.”

Here are some suggestions for dealing with frosted corn where silage is a viable alternative:

Don’t rush into harvesting corn after the first frosty night. Immature corn still has quite a bit of sugar in the plant. The sugar acts like antifreeze, making milkstage corn somewhat tolerant of a moderate frost. Even if the leaves get singed, as long as they have green leaf tissue, or even if only the stalk remains green, the plant will continue to mature. Of course, when harvesting begins will depend on how much frosted corn the producer has to harvest for silage.

Don’t overestimate the drying effects of frost. Producers often look at the frostcrisped leaves and start chopping. However, leaves are only about 10 percent of the whole plant’s dry matter. Much of the moisture (and yield) is in the stalk, especially the bottom half, and this often dries quite slowly. Harvest timing should be based on a dry-matter test, not how the field looks from the seat of the pickup.

Once the plant is dead, if the husks still are wrapped tightly around the ear, start harvesting as soon as possible. A tight husk cover holds in moisture and, under warm conditions, ear molds can start within a week after the plant dies.

Use a bacterial silage inoculant when ensiling frosted corn because a hard frost may kill many of the naturally occurring fermentation bacteria in fields.

Schroeder also recommends producers get a forage analysis before starting to feed frost-damaged corn to livestock. Compared with well-dented corn, immature corn often is higher in protein, but always lower in starch and energy. Testing will determine those levels, which will help producers develop a wellbalanced feed ration for their livestock.— WLJ