Putting up good quality corn silage may be a bit of a challenge this year since dry conditions played havoc with crop quality in many parts of the country. But, that doesn’t mean it’s impossible to do.
As with any year, moisture content will be one of the biggest keys to your success — whether you make your own silage or hire a custom harvester. It’s essential you know when to “pull the trigger” and begin chopping.
That’s because moisture levels are directly correlated to fermentation processes, fermentation speed and fermentation outcome. Ensile too early, or when corn is too wet, and you end up with abnormal fermentation, excessive seepage and poor quality silage. Ensile too dry, and quality is also compromised.
Obviously, maturity dates offer timing assistance, but 110-day corn isn’t always ready for harvest at 110 days. Harvest timing is heavily dependent on the growing season and weather conditions, and therefore, it may be a more difficult to peg in a drought year
Don’t rely on firing for timing
Don’t let your eyes deceive you, advises Glen Shirk, Penn State University extension dairy agent. This is especially true with drought-stricken corn. The leaves may be brown and dry, but the stalk and ear may still contain fair amounts of moisture. Also keep in mind that the bottom leaves only represent a small percentage of the plant’s total weight, so the impact of firing on whole-plant moisture is usually less than what you might expect.
For example, using results from 2001 Penn State test plots, if you had ensiled droughty corn at 50 percent firing, the moisture level could be as high as 74 percent. This results in a negative outcome characterized by abnormal fermentation and poor silage quality. Overall, when corn was in the ideal moisture range of 60 percent to 70 percent, firing ranged from 10 percent to 60 percent.
The best way to determine plant moisture is to cut about six representative stalks, chop them to ensiling length and test them for moisture levels, Shirk suggests.
Predict dry down dates
Once you have initial results based on these stalks, use the following formula to figure out when harvesting units need to hit the field.
According to Penn State findings, once kernels are well developed and the kernel milk line begins to regress, whole-plant moisture levels drop about 0.65 percentage units per day.
Therefore, if you plan to ensile corn at 65 percent, but it is currently at 72 percent, the moisture content needs to drop by 7 percentage points. Divide these 7 percentage points by 0.65 and you’ll determine that the crop will be ready in about another 11 days.
Just remember that significant changes in plant and weather conditions will affect this rate. So, keep one eye on the weather map and the other on your corn crop. And be ready to alter your harvest plans as neccessary.