Don't Panic Yet Just Because You Can't Plant Corn

It's too early to declare this a late-planting, low-yield potential season.

Published on: Apr 23, 2009

No, 2009 won't go down as a year you or your neighbor got going super-early with planting, at least not in most areas of the Corn Belt. A wet weather pattern has virtually shut out field activity across most of the region since late March.

So is it time to panic? Is it time to throw in the towel and accept the fact that yield potential will be down this year? Your father or grandfather would have found that question ludicrous. Very little corn went into the ground in April as recently as 30 years ago, and even fewer soybeans. Yet data amassed by university researchers and seed corn companies in their own work over the past two decades plus indicate that best yields, especially for corn, typically come from fields planted early in the season. For many areas of the central Corn Belt, that typically means sometime in April, often by mid-April.

On the flip side, however, the same data sources indicate that the window in which yield potential varies little runs from early-to-mid April to early May for corn. That means that there's still time for the weather patterns to shift, soils to dry out, and planters to roll. And the most recent of all memories, last season, indicated that even with significant weather delays over huge chunks of the Corn belt, it's still possible with today's genetics and production systems to produce near-record corn yields.

One of the farmer's best friends this time of year is the Corn & Soybean Field Guide, published by the Crop Diagnostic Training Center at Purdue University. It's housed under the umbrella of the Purdue University Agronomy Department. Nearly 50,000 copies of this pocket guide will likely be distributed throughout the Midw2est this year. It's published every year, and is filled with information about corn and soybean production, including handy tables and field scouting guides for insects, diseases, weeds, fertilizer deficiencies and more.

One item feature there is a full-page table about how planting date affects yield potential for corn. It's based on long-term data collected form a number fo sources. The actual outcome may be different in any one season or at an one location. But overall, it's an indication of what researchers and agronomists have found to be true over time.

This chart assumes the period when you can reach 100% of yield potential for corn is April 25 to May 5, at populations ranging from 26,000 to 34,000 plants per acre. You may need to adjust your thinking in planting dates if you farm on the northern or southern fringes of the Corn Belt region.

Suppose you can't plant until May 10, but still obtain plant populations of 28 to 32,000 plants per acre. According to the table, you still have 97% yield potential. If your best possible yield was 200 bushels per acre, now it's 194 bushels per acre.

Suppose you're delayed until May 20. Now yield potential is 91%, or less than 20 bushels per acre off the top yield possible if the original possibility was 200 bushels per acre. Last year proved that it's sometimes possible to punch that number back higher.

The point is clear. The table indicates that although you may be getting nervous if your planter isn't rolling by now, it's entirely too soon to panic. There's still plenty of time to plant a great crop. Yes, that may change if the wet weather stretches into mid-May. But past history says it's best to take the calendar one day at a time, especially at this time of the year.

To learn more about Purdue's Corn & Soybean Field Guide, contact officials at 765-494-3755, or email: media.order@purdue.edu.