by: Dr. R.L. (Bob) Nielsen, Purdue University (edited)
The “dog days of August” are upon us with warm and uncomfortably muggy days accompanied by warm and uncomfortably muggy nights. Invariably, conversations down at the local cafe over coffee or the neighborhood tavern over a few beers turn to the inevitable opinion that “…these warm nights simply cannot be good for the corn crop.”
Remember last year? We had very few warm nights throughout the growing season, our corn was rarely under any heat or moisture stress. How did that turn out – many of you grew some of the best corn ever!
One of the concerns often expressed about the effects of warm nights during the grain fill period is that excessively warm nighttime temperatures result in excessively high rates of maintenance respiration by plants. That physiological process oxidizes photosynthetic sugars and provides energy for the maintenance and repair of plant cell tissue, which helps the photosynthetic “factory” continue to operate efficiently. While useful for maintaining the function of the photosynthetic factory, maintenance respiration does not directly increase plant dry weight.