There is a "quick" method of estimating time to harvest a drought damaged corn field: the "squeeze test".
- Select a few stalks (like described in the previous paragraph) and chop them into pieces about the same size that the silage chopper would using a heavy knife or cleaver. Also, you could chop a round of the field with a silage chopper and sample the chopped material. Grab a hand full of the chopped material and squeeze it for 30 seconds.
- If the juices drip easily from the material, then it is too wet. In this situation, wait to chop in a couple of days or test again in a couple of days.
- If the sample doesn't drip any juices from the squeezed material, then slowly open your hand.
- If the stalk material remains compacted and doesn't fall apart or quickly expand back , the moisture level is acceptable for ensiling.
- If your hand is not wet and the stalk material falls apart when you open your hand, the material is too dry to ensile.
If the chopped silage is too wet:
- Stop chopping and allow the field to dry.
- OR -
- Add whole corn, dried distillers grains, or ground dry forage.
To avoid the nitrates, the chopper head could be set to leave an 8 inch stubble. This will result in a reduction in yield. The ensiling process will reduce nitrate 30 to 60 percent, so a compromise is leaving a 6 inch stubble.
Droughted corn silage will be 85% to 95% the energy value of regular corn silage depending on the number of ears on the stalk. The protein content can be slightly greater than regular corn silage.
Before feeding, sample and test for moisture, energy (TDN), crude protein, and nitrates.
Pricing drought corn silage is a bit of a challenge. Rule of thumb has been that each ton of 65% moisture corn silage in the bunker is priced at 9 to 10 times price of a bushel of corn (normal, well-eared corn). Pricing the standing crop is a little more difficult to determine. Below are two ways some have priced it in the field.
- Ton price is 5 times price of a bushel of corn (earless corn)
- Ton price is 6 to 7 times price of a bushel of corn (low grain corn - less than 100 bu/A).
It is hard to estimate the amount of silage that will be produced in a corn field that has been droughted out. The National Corn Handbook estimates the tonnage of a drought damaged corn field is related to the corn yield if the field were allowed to be harvested. For each 5 bu/acre corn yield results in a ton of corn silage per acre. If the droughted corn field were going to yield 15 bu/acre it would produce 3 tons of corn silage per acre.