Get Ready for Corn Silage Harvest

All across PA corn silage harvest has been going on for the past 2 weeks in some locations. In many of these early harvest areas the 2012 drought was the reason for early harvest but now crop maturity is driving the harvest of the well-developed crop.
Early reports from producers and consultants are noting that many hybrids are at drier whole plant moistures than anticipated by producers. This can lead to many challenges at filling and feed out. Be certain to check your hybrids quickly to be certain that moisture levels are not going to create problems for you at a later date.

Depending on storage structure type, corn silage is harvested when whole plant dry matter reaches 30 to 35%. Optimum dry matter content for bunker silos is 33 to 35%; ag bags – 33 to 37%, conventional upright silos – 35 to 38% and oxygen-limiting silos – 40 to 45% dry matter.

Proper moisture at harvest is critical and there is a wide variation in the actual moisture of the crop based simply on the milk layer. The most accurate measurement of whole plant moisture is to conduct moisture testing. Begin by taking a few plants from selected fields at dent stage. Run these plants through some type of chopper or lawn mower and thoroughly mix together. Use a Koster tester or a microwave to determine whole plant moisture.

This moisture can then be used to predict harvest date. The expected dry down rate for corn silage is 0.5 to 0.6% per day. For example, if your crop moisture levels test at 70% and your target harvest moisture is 65% you need an additional dry down of 5%. Dividing by the dry down rate of 0.5 to 0.6% per day indicates that you can expect to be harvesting in 8 to 10 days. Be sure to test the actual moisture content again at and during harvest. When moisture drops below 60% the rate of dry down increases beyond 0.5%/day and the crop will become too dry for optimum fermentation.