May 22, 2013
Concentrated Planting Window Results in Concentrated Pollination
Most of the 2013 U.S. corn crop will be planted in a narrow window this spring which means that the crop will also go through its developmental stages including pollination in a concentrated period as well. Generally pollination occurs about 60 days after emergence and the 2013 corn crop should hit 50% emerged sometime later this week. As a result, the U.S. corn crop will probably hit 50% pollination sometime during about the third week of July.
It's always better to spread out your production risks by planting over a longer period of time with hybrids of different maturities so that pollination occurs over an extended period as well, thus reducing the risk of adverse weather during the peak of the pollination period. This year though, the pollination period should be as concentrated just like the planting has been.
Delaying pollination until later in July carries with it a greater risk of adverse weather that may adversely impact pollination. A week or two delay in pollination doesn't necessarily mean that the temperatures will be hotter, but it does increase the risk of dryer soils.
When there are problems with pollination, it is usually caused by an interaction between temperatures and soil moisture. If there is ample soil moisture, then temperatures in the mid-90's would have very little impact on the success of pollination. If the plant is under severe moisture stress, then temperatures in the mid-90'Ps could result in poor pollination. The worst combination of all is an extended period of dryness leading up to pollination and then extremely high temperatures during pollination. That is what happened in 2012 and the result was a nationwide corn yield of only 123 bu/ac.
This year it is going to be very important to monitor the soil moisture across the Corn Belt during the first half of July. If the soil moisture is declining during early July, that could be a precursor to problems during pollination.