- Grain corn: choose a hybrid with a Crop Heat Unit (CHU) that matches the area. You will need grain corn to reach physiological maturity (black layer) to be successful.
- Silage and Grazing corn: choose a hybrid that is 150-200 CHU later than the area.
- ie CHU range from 1900-2000 CHU then select hybrids with CHU around the 2150-2200 CHU range. You do not need to reach black layer, but you do need to reach 2/3 milk line for ideal chopping and feed value.
Grain Corn Requirements (Silage in brackets):
- Nitrogen- 1lb of N per bushel (9-10lbs per wet Metric/tonne)
- Phosphorus- .44- .63 lb per bushel (3.5lbs per wet M/tonne)
- Potassium- .28- 1lb per bushel (12lbs per wet M/tonne)
- Sulphur- 0.07-.15lb per bushel (10lbs per wet M/tonne)
- Zinc- 1lb total
Now, assuming you are growing a Roundup Ready Corn Hybrid, you will be applying Roundup 2 x .67L/ac up to the 8-leaf stage. You also have some flexible tank mix options including Armezon which the staging window is wide and no re-cropping restrictions for next year.
There are some phenoxy herbicides such as 2,4-D and Bromoxynil that can be tank mixed as well BUT you must consult with your seed supplier as not all corn hybrids are tolerant to these products.
Seeding Equipment and Timing
Grain and silage corn need to be planted as early in May as possible keeping in mind that cold soils and rain can cause chilling injury. Grazing corn has more flexibility and can be planted later in May.
Whether it is grain, silage or grazing, maximum yield and nutritional value come from fully developed ears (cob) filled with seed!