Options for Drought Damaged Corn

Corn plants in southern Wisconsin are rapidly deteriorating in 90+ temps combined with the pollination time, which is the highest water use rate in plant life cycle.

Last week I traveled across southern Wisconsin and saw some badly damaged corn acres.  Many areas across the Midwest are facing similar situations.  In yesterday’s crop report, I read that many farmers are chopping corn now and considering silage.

Certainly, each farmer wants to use this crop in the best possible manner.  Maybe that means salvaging it.  Maybe that means destroying it completely.

Farmers need to 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.  Testing the silage both before it is chopped and after it has fermented in the silo is a good idea to be sure it’s safe for consumption.

When deciding the best use of a damaged crop, here are a few things to consider:

  1. Consult with your insurance company to ensure proper guidance before removing damaged crop.
  2. Test for nitrates before and after harvest.  Immediately freeze samples and send to lab for testing.
  3. Check moisture levels.  It’s ideal for whole-plant moisture to test 65-70% for best fermentation and quality.
  4. Chopping and ensiling is the preferred harvest method.  Chop fine for best packing results, cut high to reduce nitrates.
  5. Consult with your feed advisor.  Drought can increase the levels of nitrate in many instances. High levels of nitrates in a diet can lead to methemo-globinemia.

A detailed summary of these considerations follows:

  1. Insurance companies vary in how they calculate losses.  Some request leaving rows behind as they are so overwhelmed with loss claims.
  2. A nitrate is basically unused plant nutrient because plant metabolism is slowed.

Derived from Hicks, Minnesota
Notice that the most nitrate accumulates in the lower portion of the stalk

When an animal eats a feed containing high nitrates, the nitrate is converted to nitrite during digestion. Eventually, it combines with hemoglobin (our oxygen carrying red blood cells). This significantly decreases the ability of the blood to carry oxygen, and tissue damage begins as our body needs oxygen to survive.  The total amount of nitrate consumed, rather than the concentration in the tissue, is the critical consideration.

Guidelines to Use of Feeds with Known Nitrate Content

SOURCE:  Nitrates in Forages by Keith Kelling, Extension Soil Scientist, UW-Madison/Extension

   3. Testing for nitrates is important for a baseline understanding of nitrate levels.