Chopping the crop for silage is one way to retain some value of the crop before it wilts down in the drought, even though the dry matter tonnage produced may be 10 to 50 percent lower in a drought compared to normal corn silage.


“If the corn is barren with little or no ear showing, one general rule of thumb for figuring what the tonnage may be is to multiply one to 1.5 tons of 30 to 35 percent dry matter corn silage per foot of stalk,” said Schnakenberg.

Normally, corn is chopped at 60 to 70 percent moisture, depending on the type of storage used and when the milk line is one-half to two-thirds down the kernel, according to Dr. Rob Kallenbach, state forage specialist with University of Missouri Extension.

“Drought-damaged corn usually has 85 to 95 percent of the feeding value of normal corn silage. One concern is that drought-damaged corn sometimes has either too much or too little moisture for optimum fermentation so producers should monitor the moisture level of the corn that is chopped,” said Kallenbach.

According to Schnakenberg, corn should be chopped to three-eighths to one-half in length to help the crop pack better in storage and exclude oxygen.
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“Farmers should also be aware of the dangers of excessive nitrates in corn that was intended for grain. The drought has caused a buildup of nitrates in the forage that could be toxic to cattle if grazed or green chopped,” said Schnakenberg.

Making drought-damaged corn into silage is the best approach to reduce nitrate issues. The fermentation process can potentially reduce the nitrate content by 20 to 50 percent. Testing the silage both before it is chopped and after it has fermented in the silo is a good idea to insure it is safe for consumption.

According to Kallenbach, producers who find that nitrate levels are too high could increase the cutting height eight or 10 inches since nitrates accumulate in the lower stalks. Another tip includes diluting the silage in a ration with other low-nitrate feedstuffs.

Some producers may decide to wrap corn into a big round bale for baleage. Fermentation is more challenging in corn using this practice but it is an option with the proper equipment.

Instead of the normal four-mil plastic thickness for normal grass silage, drought-damaged corn should be wrapped to a six-mil thickness to help avoid corn stalks from poking holes in the plastic. FG

—From University of Missouri Extension Southwest Regional News Service