In July, there were 18 nights that were warmer than 69º F (nighttime minimum); and the daytime maximum temperature was warmer than 86º F. The potential impact of these temperatures can be analyzed from two viewpoints.
First, the elevated nighttime temperature means less net photosynthate (energy) available daily to increase corn yields. This yield loss is the direct result of the higher nighttime respiration rates. The “net energy” is equal to energy produced by photosynthesis during the day minus the energy utilized by the plant for respiration during the night. This “net energy” provides for the daily gains in yield during grain fill. This can translate to yield reductions of up to 1.2 bu/A/day or in our case, more than 20 bu/A.
Second, the number of days necessary to reach black layer from mid-pollination is reduced. For instance, a corn variety that normally requires 55 days may only need 50-51 days to go from mid-pollination to black layer. When we see reduced days, lower yields are possible.
That’s it for now, have a good week.