Farm Horizons, February 2007
Recommendations for corn on corn acres
By Dave Schwartz
There is no question that farmers in Minnesota will be growing more corn acres in 2007. It’s possible that this trend will continue into the future if the corn market remains strong.
A big unknown, though, is planting conditions in April and May. This could change the picture significantly, but at this time, the intent is that significantly more corn acres will be grown.
As I think of what growers need to consider when planting corn on corn, the following thoughts come to mind:
• First, and probably most important, plant a corn rootworm hybrid. I have been surprised what a strong yield advantage there is to this new technology.
An agronomist from the University of Illinois gave a presentation at the Crop Pest Management Shortcourse in Minneapolis in December. In the University of Illinois studies, it was estimated that there is a 40-bushel per acre response of corn rootworm hybrids over insecticides at planting time where corn is planted on corn.
A few years ago, I would not have believed such a yield advantage possible. Evidently, corn rootworms put more pressure on corn plants than what we once thought.
• Second, growers should choose their best ground to come back with corn a second year.
Researchers have found more problems, as in yield loss, when corn is planted the second year on droughty soils.
• Third, use a starter fertilizer. These corn plants will be under more stress, so it’s important to create a near perfect environment for them to grow.
• Fourth, growers should incorporate their nitrogen to reduce contact with the old crop residue. Studies show that nitrogen can become tied up if, for example, 28 percent nitrogen is applied over the surface.
I would also recommend adding an additional 30 to 40 pounds of nitrogen above what is normally applied in corn/soybean rotations.
• Fifth, use a hybrid that is recommended for corn on corn. These hybrids normally have a strong root system and a disease resistance package.
• Finally, I would recommend using row cleaners at planting so the surface area over the seed is black. This enhances soil to seed contact, improving germination. Soil temperatures will also be warmer, improving stands.
Back in the ‘70s and ‘80s, when growers received farm program deficiency payments, planting corn on corn was quite common so we know it can be done successfully.
One major change since then is that there is far more rootworm pressure. This is why managing CRW with a corn rootworm hybrid should be a priority.