One Year’s Data is Just That - One Year!

Agronomist advises against basing too much on one year’s results.

Published on: Jan 7, 2008

The Corn Illustrated plots give you a chance to see what happens on a real farm when various theories that agronomists and crop breeders talk about are put to the test. Some of the studies reported in the project are replicated tests. Others are just demonstrations intended to raise questions and fuel debate. What the plots were not designed to be is the last word on what decisions you should make for your farming program for the upcoming ’08 planting season.

Instead, base your decisions upon results from multiple locations and multiple years, if possible. If it’s a practice that hasn’t been tried very much, at least look for some locations where it has been tried, plus seek the advice of agronomists and university researchers. It’s likely that some researcher somewhere has tried the concept before.

Dale Hicks, University of Minnesota Extension corn specialist, made this observation about the Corn Illustrated plots while helping piece together a story on which hybrids should be planted first- early, medium or relative-late maturing hybrids? The story will appear in the February issue of Corn Illustrated in your Farm Progress magazine.

Hicks noted that the results of the ’07 Corn Illustrated plot represented one test at one location- Edinburgh, Ind., in one year- 2007. And he noted that it was a very stressful year. Only a bit over 5 inches of rain fell from May 1 through Sept 15, and most of that came in small showers. There were 40 days of 90 degrees or higher temperature, with the most of those coming after August 1. The average in that part of the Corn Belt is less than 20 days of 90 degrees or higher per season, with closer to 12-15 inches of rain during the same stretch being average. On top of this climate variation, the soil was underlain with gravel at three feet. So late in the season, hybrids ran out of water, even if they were performing well up until that point.

The hybrids were planted at three planting dates- May 7, May 17 and May 29. Results held relatively close to what might be expected by most agronomists through the first two planting dates. But the fuller season hybrid was impacted hardest, and although it performed better planted early than planted any other time, it still yielded less than other hybrids in the plot. All four hybrids of varying relative maturity dates from 105 to 119 days tanked at the May 29 planting date, yielding from about 25 to 50 bushels per acre. Plants simply ran out of water.

Hicks’ observations are well taken. To make conclusions meaningful, it’s important to include observations from those who have tried the same type of test many times, at various locations in various years. Generally, most agronomists agree that no matter where they are in the Corn Belt, the best bet if you’re concerned only about yield is to plant the fullest-season hybrids for the area first. Some say follow with mid and finally early-season hybrids- others suggest reversing or mixing the order after planting the full-season hybrids first. They also note that what’s full-season for one area may be medium for another. For example, Roger Elmore Iowa State University Extension corn specialist, says that in Iowa, most hybrids recommended fall in the 102 to 112 day range. A 112 day hybrid is considered mid-season from Indianapolis across through Champaign and on through central Illinois.

The bottom line? Let the results of the Corn Illustrated project spur your thinking. Reevaluate what you do and why you do it. But don’t make major shifts in how you do things based on one article, or one test. Instead, let it be your guide that leads you into investigating the situation more fully.