High Humidity and Temperature and Corn Pollination August 4, 2017
(Excerpted from Extension Educator Nathan Mueller's blog: http://croptechcafe.org/does-high-humidity-and-temperature-disrupt-corn-pollination/)
Will the high temperatures and humidity experienced in the last few weeks impact corn pollination and kernel set? Here’s a summary from a UNL CropWatch article “How Extended High Heat Disrupts Corn Pollination” written by Tom Hoegemeyer in 2011.
- High humidity helps reduce crop water demand which is helpful for rainfed corn
- Corn heat stress can occur starting at about 92 degrees and higher
- When soil moisture is sufficient, one day of 95-98 degrees has little to not impact on yields.
- Temperatures above 95 degrees several days in a row will decrease the volume of pollen shed and pollen viability (time that pollen remains viable to fertilize silks)
- Higher nighttime temperatures burns more sugars that were produced by the plant during photosynthesis during the day. Not ideal for yield potential.
- Hybrids that silk early compared to pollen shed more at risk of silk desiccation from high temperatures, though less risk with high humidity.
- Dehiscences, releasing of pollen from anthers, is triggered by the drop in humidity and a temperature increase. So with extreme humidity and a lack of drop in humidity in the morning, pollen shed may delay until later in the day.