Weather influcences corn crop this season
By Randy Buhler
CSU Extension agent, agronomy, Logan County
Weather has played a major influence on the corn crop this season. A slow start, mild summer, and killing freeze on Oct. 3 shortened our anticipated growing season.
The measured corn growing degree-days for Sterling as of Oct. 3 was 2413. We normally expect 2700 to 2800 growing degree-days. This cooler season played heck with relative corn maturity, so that those farmers pushing yield with longer relative maturity were caught with immature corn. Immature corn will not dry down, while standing in the field, to a marketable grain moisture percentage of 15.5 percent.
Farms with aerated storage and driers can manage harvest in a timely fashion, but incur drying costs and shrinkage. Most farms in our area are not equipped with driers and many do not have aerated storage. That leaves field drying as our primary management practice.
Based on an Ohio study of four hybrids, planted at three populations, and harvested during October, November, and December, the results are informative for our current situation. Nearly 90 percent of yield loss occurred after mid-November. The most field drying (5.8 percent) occurred from mid-October to mid-November. After that date, drying was less than 0.5 percent at the mid-December harvest.
Lodging greatly increased after the mid-November harvest date. Yield loss averaged 13 percent over the three harvest dates. Most of the loss (11 percent) occurred after the mid-November harvest date.
In 1972, a Halloween eve blizzard caught corn growers across Weld County by surprise. Corn was blown down and remained under snow and ice until the following February. Harvest waited until the ears thawed loose and could be pulled up with the gathering points. Grain quality was okay, but with black spot saprophytic fungi readily evident. Marketing was difficult unless you could take your corn to a feeder, who mixed it in with good quality corn and fed it right away. That restricted the amount of corn you could harvest and deliver each day.
It seems a similar situation is in place for this season. You can expect field loss to increase, drying rate to decrease markedly, and for harvest to depend on your marketing opportunities. Manage to salvage your yield as quickly as possible. Do not count on delayed harvest to improve your situation. One point in your favor is the better stalk quality available from our current corn varieties.
For next season, consider carefully the relative maturity of corn varieties you pick. With erratic climate variation, play to the safe side and use relative maturity corresponding to the 2500 growing degree-day rating for the Sterling area.
Corresponding growing degree-day accumulation for 2009 was 2466 units for Akron, 2460 units for Haxtun, 2540 units for Holyoke, 2609 units for Fort Morgan, and 2543 units for Yuma.