What should we expect for maturity?
Sep 03What should we expect for maturity?
I have been fielding a lot of questions lately about how many heat units we have accumulated and if we are behind last year. Below is an example of CHU accumulation demonstrating how 2014 compares to 2013 and the 10 year average. All data was collected from FarmZone.com. FarmZone has a great database that lets you calculate CHU across historical dates and locations across Canada.
The data presented is for Chatham Kent, Ontario.
As of August 26th, we have accumulated 2704 CHU since May 1st. Last year on this date we had accumulated 2820 CHU. We arebehind by 116 CHU compared to 2013.
The 10 year average to this date is 2760 CHU. Therefore, we are behind by 56 CHU from the 10 year average.
What is interesting to note is that I also did this 10 days ago and we were at 2435 CHU. That means we accumulated 269 CHU in 10 days for an average of 26.9 CHU per day.
So what does this all mean? Basically, we are colder than last year!
We need to understand what CHU actually means. As an example, let’s use MZ 4640SMX, rated at 3150 CHU. This means that MZ 4640SMX requires 3150 CHU to reach black layer, an important requirement for corn to mature. It is important that this occurs before the first frost for maximum yield potential.
On average, we generally accumulate anywhere from 20-30 CHU per day. Accumulation of CHU depends on the maximum and minimum daily temperatures. If we use 20 CHU as an average daily accumulation, we need approximately 22 days to reach black layer on MZ 4640SMX, since we need another 446 CHU (CHU required  – CHU accumulated to date  = CHU remaining ). This is very achievable. Remember the above calculation used 20 CHU accumulation per day. We still have the month of September left to accumulate CHU. Typically, September has been a good month for us over the past 5 years, with an average accumulation of 679 CHU.
We need Mother Nature’s help for no early frosts to finish the crop! Corn might be wetter than we would like at harvest, but on the plus side, yields appear to be above average.
Please note: The numbers quoted above are based on corn being planted on May 1st. As most are aware, the majority of corn was not planted on May 1st this year. You need to go to FarmZone, and run your individual numbers. If I were to use May 20th as a planting date, the accumulated CHU would be 2457. Using this date, we are 693 CHU behind maturity. That is a difference of 247 CHU from what was presented above.
Chuck Belanger, Maizex Seeds Yield Specialist, North Essex and South Chatham-Kent Counties