Corn is beginning to tassel across the country, which means corn kernel pollination is occurring. While corn silage harvest may feel like it is a ways away, research shows choppers may be hitting the fields 40-50 days after pollination.
When to Harvest
“Proper harvest timing is key when it comes to storing high quality corn silage,” says Casey Guindon, an educator in field and forage crops at Penn State University. “Optimum moisture content at harvest is essential in the promotion of fermentation, which results in high quality silage. Knowing the condition of your crop is the first step in being able to make informed management decisions.”
Guindon recommends harvesting at a moisture level of 65%, or 35% dry matter, depending on the type of ensiling system you plan to use.
“At this moisture content, the silage can be adequately compressed, and the oxygen is removed more quickly,” she says. “The quick transition to an anaerobic environment promotes the development of lactobacillus bacteria. At a lower moisture content, oxygen is not quickly excluded, and mold can continue to grow and heat the silage. At a higher moisture content, clostridia bacteria begin to grow, and create silage that smells rancid -- resulting in lower palatability and quality.”
Another way to estimate the timing at which the corn is right is to calculate the number of days after pollination, according to Emily Carolan, a territory manager for Pioneer Seeds. This can help provide an idea as to when to run plant moisture samples. However, it’s important to note that the only reliable method of determining the optimal time to harvest corn silage is to sample and directly measure the percent dry matter of whole plants.
Kernel Growth Stage | Days After Pollination |
Pre-blister | 9 |
Blister | 13 |
Early Milk | 17 |
Milk | 21 |
Late Milk | 25 |
Soft Dough | 30 |
Early Dent | 35 |
Dented | 40 |
Late Dent | 45 |
Half Milk Line | 50 |
Mature | 55 |
“Once [the corn] hits half milkline, we know whole plant moisture will start to drop, so chopping should be close by,” Carolan says.
When the moisture content is right, start harvesting earlier rather than later, recommends Donna Amaral-Phillips, an extension professor at the University of Kentucky.
“Harvest over as short a time frame as possible,” she says. “Quality and consumption drops off after [you reach] 40% dry matter.”
Silage Storage
Once the decision has been made to harvest, there are several factors to consider when it comes to storage.
For silage piles and bunkers, the silage should be spread in 4 in. thick layers in a wedge configuration at a speed of 1.5-2.5 mph., according to Amaral-Phillips. Make sure to not turn around on the silage surface as this can loosen the packing density. Packing is complete when the surface is covered with tire tracks and is smooth.
For silage bags, make sure that the bagger is working properly and that there are no holes or tears in the plastic. If possible, try to set the bags on a concrete or asphalt surface to minimize mud at feed out, Amaral-Phillips recommends. Mud decreases feed quality and increase the possibility of unwelcome bacterial contamination of feed.
