Start checking maize crop maturity about three weeks prior to when you think you’ll be starting your silage harvest. Good quality maize silage is best made when whole plant dry matter is between 30-40%
If harvested is less than 30% dry matter the silage stack will be wet resulting in stack leachate, this leachate represents nutrient loss. However, if dry matter is above 40% stack compaction and air exclusion is much more difficult.
One important maturity indicator is the maize kernel milk line: where the milky liquid changes into the harder darker starch line. By simply snapping a cob in two and examining the upper portion’s kernels, the milk line can be seen. When the milk line is one third of the way up from the bottom of the kernel the plant is in the 28-32% DM range. See image here.
Milk line is only indicative that harvest time is near and there are other indicators needing consideration. In-field estimation of crop DM requires considerable experience, most contractors and technical advisors have experience in harvest scheduling and can offer advice on harvest maturity.