Q: What are some factors to consider when establishing a corn crop for grazing or silage?
A: Corn is a great option for grazing or silage, but there are several factors to consider when you’re establishing your corn crop. Crop rotation, fertility, plant depth and population, planting date and soil temperature and weed control are a few.
In terms of crop rotation, ask yourself these questions: What field are you planning to use? What was grown there last year and the year prior? Did you spray herbicides on the field last year? Do you have any herbicides that may carry over and affect corn emergence?
For fertility, a general rule of thumb is to apply 12.5* lbs. of nitrogen for every one tonne per acre of silage targeted (one tonne of silage = about 12.5 bu./ac. of grain corn). Corn uses nutrients in the following ratio: four pounds nitrogen to two of phosphorus and three of potassium. Apply 70 per cent of the total seasonal nitrogen requirement prior to planting and the remaining 30 per cent as late during the growing season as equipment allows.
Planting date, seed depth, plant population and temperature are also important. Plant kernels at least 1-1/2 to two inches deep. Aim for minimal plant stands of 28,000 to 30,000 plants per acre. Many growers are increasing their silage stands to 32,000 to 34,000 plants per acre as this creates thinner stocks which can often translate into better feed values.
Planting date is one of the most important factors in stand establishment. If a cold spell is expected during planting time, stop planting one or two days in advance. Alternatively, if warming trends are expected, plant with confidence. Allow seed to begin hydration in warmer soils to minimize damage due to cold imbibition.
When it comes to weed control, a pre-seed product with your glyphosate burn-off is a must. Weed competition is most damaging early in the growing season. If seeding into canola stubble, be aware of potential flushes of volunteer canola.
Gary Topham, P. Ag, CCA, is a manager of agronomic services with Nutrien Ag Solutions in Manitoba.
*Editor’s Note: An earlier version of this article stated that 1.25 lbs. should be applied. We apologize for the error.