By Daniel Davidson

DTN Agronomist

OMAHA (DTN)--Bob Nielsen, an Extension corn specialist at Purdue University, said the most important factors that can maximize corn yields are hybrid selection, planting date, seeding rate, use of starter fertilizer and seed insecticides and tillage practices.

Nielsen said the main goal at planting is to achieve fast and uniform germination and emergence followed by vigorous early development. Selecting the right genetics and planting practices will help growers achieve this goal.

Selecting the right hybrid is the No. 1 factor when growing corn. Growers need to identify consistently superior yielding hybrids, regardless of tillage system. Good hybrids in minimum tillage tend to also be good in no-till. Within that group of superior hybrids, growers should select those with characteristics important for their tillage system.

Farmers need to look at data from past performance at several locations, not just their personal farm.

If they're growing corn under no-till or in heavy, wet soils, for example, they should look at cold tolerance for germination, early seedling vigor and seedling disease tolerance.

Selecting the right tillage system contributes to yield, profit, soil improvement and conservation. In corn, the goal of tillage should be primarily to loosen the soil and prepare the seedbed for planting. This means incorporating crop residue and creating a firm seedbed for seed placement.

Growers should select tillage practices based on their conservation practices, the amount of residue they want to retain and the type of soil they are managing.

Corn should be planted when soil temperatures reach 50 degrees Fahrenheit. If soil temperatures aren't rising or if conditions are too cool or too wet, delay planting until later.

No-till fields, while a bit cooler and wet than conventionally tilled fields, will be firmer, so they can be planted earlier. Growers need to remember that delays in planting corn can result in a reduction of yield. Unfortunately, corn yield drops off sooner with delayed planting than soybeans.

To find the optimum planting rate, select a target population that yields high and consistently for the local environment. To cover seed or early seedling losses, plant 5 to 15 percent over the target population. Boost target plant populations by 5 to 10 percent when seeding early maturity hybrids. When planting under extreme conditions, up the seeding rate 5 to 15 percent.

Deciding to use starter fertilizer should depend on the likelihood of getting a response. The probability of getting a response is often greater for no-till soils than conventionally tilled soils.

When high levels of phosphorus and potassium are in the soil and the seedbed is warm, there's little chance of a response to starter fertilizer, and there's also a small risk to yield if a starter is not used.

When high levels of phosphorus and potassium are in the soil and the seedbed is cold and wet, there is little chance of a response to phosphorus and potassium but a strong probability of a response to nitrogen. Use starter and apply 20 to 25 pounds per acre of nitrogen.

When there are low levels of phosphorus and the seedbed is cold and wet, a strong probability of a response to phosphorus and nitrogen exists. In that case, apply starter but aim for 20 to 25 pounds an acre of nitrogen.

There are a number of insects that can attack the corn seed and seedlings. Insecticides historically have been spread over the field or planted in the row.

Insecticides today, however, can be applied during seed processing and targeted at secondary insect pests including wireworms, seed corn maggots, white grubs, flea beetles and black cutworms. Costs range from $4 to $6 an acre.

Pests are not a problem in every field, so blanket applications run counter to integrated pest management concepts. Fields that usually have pest problem will likely benefit most from the use of seed applied insecticides.

Growers paying attention to these six factors at planting will get their crop off to a good start and have a better chance of reaching their yield goal.

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