The ideal time to harvest your maize silage crop is when the whole plant drymatter is between 30-38%. Estimating the kernel milk line score, the plant cob to stover ratio and the plant drymatter content will help you determine if your crop is ready to harvest. Please note that the following guidelines should only be used to determine if the crop is ready to harvest. There is a Code of Practice for the Trading of Maize Forage available free of charge from www.far.org.nz.
The whole plant drymatter can be estimated by looking at the milk line of the grain. To check whether your crop is in the range of 30-38% drymatter:
- Take a cob from a plant that is at least 20 rows into the crop.
- Break / snap the cob in half and discard the end of the cob that was attached to the plant.
- Hold the point of the cob downwards and remove a kernel from the "snapped" end.
- Slide your fingernail along the length of the kernel starting at the flat (dented) end of the kernel.
- Note the point where the solid starch ends and the liquid milk begins.
The hybrid will be ready for harvest when the milk line is two thirds of the way down the kernel.
The milk line test is only indicative that harvest time is near. The only sure way to test plant drymatter is by sending a plant to a suitable laboratory or conducting a microwave drymatter test.