The 3rd Annual Great Ontario Yield Tour came to a close on August 30th 2018.  Greg Stewart, head agronomist with Maizex Seeds along with Moe Agostino from Risk Management presented final yield estimates this past month.   Corn came in at a whopping 179.5 bu/ac as a provincial estimate.  Soybeans followed suit with a provincial yield estimate of 50.2 bu/ac.  So will these yields be right?


The question of being right or accurate has become much more clouded the past few years.   The real questions that need to be answered are: “Have they used the right factor for how many kernels will be needed to make a bushel?  And what about kernel weight? 


The ability to count the number of kernel rows in girth and the number of kernels in a row comes down to scouting properly and then just applying simple math. The # of kernel s round x # of kernels in length x your plant population/ac with a harvestable ear will determines how many kernels will be produced in that acre. I.e. 16 kernels round x 35 kernels in length x 32 000 plants/ac that have a harvestable ear =17,920,000 kernels/ac.  Simple enough.


Now what about 1000 kernel weight.   This is not the same as discussing test weight of corn.  Test weight is a measurement of grain bulk density that fits inside a specified space or cup that is then used to calibrate the general quality of your product.  There is very little correlation between high test weight and high yields (Nielsen, 2014).


Instead 1000 Kernel weight is a measurement of seed size. The weight in grams of 1000 seeds.  The 1000 K weight can vary tremendously between hybrids or varieties.  In corn, the observation of extra yield the past few years is coming from the depth and size of kernels.   Below is an example that I have pulled using some of the data collected on the Great Ontario Yield Tour.  The 1000 Kernel wt. factor is the number of kernels that will make up a bushel of corn (56 lb./bu)


Attempt Harvestable Ear Count Kernel Row Kernel Length 1000 Kernel Wt. Factor  Final Yield (bu/ac)
1 32 16 35 95000 188.6
2 32 16 35 89000 201.3
3 32 16 35 80000 224.0

In this example the final yield (bu/ac) could swing by 18.7% from low to high. This is how the “experts” can be out by a fair margin even when the other diagnostic numbers add up.


At Maizex we have started thinking more about this 1000 kernel factor as our yields have been increasing more than what projections would predict using industry agreed “factor” numbers.  At our Maizex Agronomy Plots located across the province we have just begun to scrape the surface of this topic with trails like adding foliar fertilizer at or after pollination. 


What decisions and management strategies can producers make throughout the entire growing season to aid in this relatively new conversation?   Greg Stewart is incorporating ideas into our Agronomy Plots for next year.  It wasn’t that long ago as producers that we would plant the corn seed, provide a little management for weed control and nitrogen and then come back in the fall to harvest our rewards.  


Wow how things have changed!  Stay connected to our Maizex Agronomy Newsletters to learn more!