You can earn free seed by completing the Crops Knowledge Quiz in the December issue of Indiana Prairie Farmer. Entries must be either postmarked by Jan. 15, or delivered by email by midnight, Jan. 15. Prizes include free seed from Beck's Hybrids for first, second and third place.
We've already revealed answers to two questions in the 10-question multiple-choice quiz. Here are two more. So if you haven't entered yet, you've got 40% of the quiz aced before you start!
Two of the questions referred to corn growth in relation to heat. Driving force behind the questions was the hot summer, especially the high nighttime temperatures that blanketed much of the Corn Belt. Experts suspect it's one of the major factors behind USDA already lowering corn yield by more than 10 bushels per acre from the August estimate. Many believe the final estimate issued next week will be somewhat lower yet.
Here's a question: The highest temperature contributing to plant growth for growing degree days (in degrees F) is: a) 86, b) 76, c) 88, d)82. The answer is 'a,' 86 degrees.
Agronomists figure that temperatures up to and including 86 degrees F encourage corn to grow and develop. At temperatures above 86 degrees, they suggest there is no additional benefit to the extra heat.
At some point, it becomes detrimental. It can be as night, as already noted, if temperatures stay in the mid-60s or higher. Or it can be if extra heat occurs at pollination time, during grain fill, or when plants are already stressed by dry conditions.
This is why in the Growing Degree Days formula, 86 degrees is the highest number that you can compute in the formula. Even if the high temperature for the day was 88 degrees, when you're figuring how many growing degree days the plant saw that day, you insert 86 into the formula, not 88.
Here's another question: The average number of growing degree days in central Indiana is: a) less than 10, b) near 20, c) near 30, d) more than 40. Some local reporters who keep weather stations reported more than 40 days of 90 degree or above temperatures in 2010 in south-central Indiana. The official number for central Indiana was in the high 30's, depending upon the exact location.
But 2010 was anything was normal. The answer is 'b,' near 20.
Ironically, 2009 featured less than 10 days of 90 degrees F or above. For many areas, there were only six, with five of those coming consecutively at the end of June, followed by a cooler than normal July.