6 Tips for Harvesting Corn Silage in Drought Conditions

Drought-stressed corn can create a range of silage harvest issues. With much of Latham Country experiencing abnormal to extreme drought conditions, risks such as high nitrate levels, variable moisture content and potential for yeasts, molds and mycotoxins must be accounted for and well understood.


Taking extra precautions to ensure a safe and productive corn silage harvest is a worthy investment. Here are a few key considerations to keep in mind this summer and fall.

  1. Consult your team. Before you make any corn silage harvest decisions, verify your plan doesn’t impact your insurance coverage. It’s also good to discuss feed-out plans with an animal nutritionist so you have a plan for when and how the forage will be used.
  2. Test chopping height. As you prepare to harvest silage, test various chopping heights for nitrates. Nitrate concentration tends to lessen as chopping height increases. Measure your chopping height and then send a 5-inch stalk sample to the lab. It is best to send at least two samples. By testing different heights across the plant, it gives you a general idea of nitrate hot zones. Also, remember that recent rains can increase nitrate levels.If you harvest high on the stalk to avoid high nitrate levels, your tonnage will be reduced. It is estimated that you harvest 1 ton per foot of no ear or poorly eared corn.
  3. Monitor moisture content. As fields vary, so too will harvest moisture. Ideally, you want to get to 65% whole plant moisture. If it is drier, packing can be difficult but mixing in small particles can help if needed.
  4. Test on harvest day. Testing nitrate levels on harvest day will give you a good frame of reference for the final product. If it shows high, do not feed it to pregnant animals, and consult with your nutritionist regarding feeding to it the rest of your livestock. Allow this crop to ensile at least 21 days, and then retest.
  5. Innoculate. Anything to help ensile and preserve the forage after chopping is important. Because drought-stressed corn can be so variable in content, moisture and packing densities, it can lead to potential issues with high nitrates, mold, yeasts and mycotoxins. A good inoculant can help the fermentation process and reduce any further problems during feed out.
  6. Test before you feed. Ensiling can help reduce nitrate levels by as much as 40-60%, but the final nitrate levels can be dependent on good packing. It is always best to test before you feed silage to livestock. As a rule of thumb, take at least two samples from different areas of the silage pack. One sample is just a number, two samples start the trend and three samples add confidence. There is just too much at stake to risk nitrate poisoning.

While Mother Nature can certainly throw some unexpected curve balls our way, these tips can help you make the best of a not-so-ideal harvest scenario.