Why were corn yields so variable in 2020?
The title above could easily be named “The Corn Train-wreck of 2020.” But I’m an optimist so we will leave it at that. So what happened? To have a greater understanding there’s some pieces to address first.
- To finish an exceptional yield, we have to first start one. There were too many issues with uneven emergence this spring. Some fields took nearly 30 days for emergence to occur for the first plants to emerge and some of these fields it took 2 weeks from emergence of the first plant to the last plant. This factor alone is the biggest/most consistent issue with poor corn yields this season. Poor final ear count is also a part of this issue.
- Lack of soil and plant energy
- Compaction—both as sidewall compaction and deeper layers in the soil profile.
- Nitrogen Issues
- Calcium, Boron, and Moly deficiencies (could include others also, but these are the most yield limiting)
- High Nitrates in plants
- Disease—Crown Rot, Tar Spot, and others killed plants prematurely
- Drainage—yes some wet holes were irreparable, but keep this next point in mind. In one of the spots we duck hunt, we tried to flood a new area this year. We pumped for 14 straight days trying to flood roughly 14 acres. In some areas of this wetland, we were holding 24” of water. We had some pump issues and had to shut the pump off for 24 hours—and after 24 hours not a single drop of water was left. This is the power of aggregate structure and proper soil drainage. There’s not a single inch of tile on this property. We figure in 14 days we pumped nearly 250,000,000 gallons of water (that’s not a typo). All gone in 24 hours. Not even a puddle left. So be careful when you say, “yeah that’s just a wet hole”. This is some nasty river bottom gumbo—but hasn’t been degraded.
- The shear amount of stresses from start to finish
- Poor management—I realize this one won’t sit well with some, but sorry it’s the truth. We have to be able to hold ourselves accountable for the decisions we make. With each decision comes Consequences, Expectations, Risk, Reward, Success, and possible Failure. And we are all guilty of “Checking The Box.” The plants we are growing are also living organisms and there is no “Silver Bullet”.
Let’s Take a Deeper Dive at #1—
The above data on Delayed Emergence is from Wyffels Hybrids. It’s very profound, and it’s also why we must spend time in our fields to evaluate the decisions we make and set proper expectations. Randy Dowdy once said, “The best thing I can see in my fields, is my shadow.” He’s 1000% correct.
There are fields from this growing season that struggled from the day they first started to emerge until the day they finally died. Some simply never recovered. The ironic part here is it wasn't just early April planted corn that suffered these consequences.
The data above shows ear size and stalk size differences of delayed plant emergence in 2 different hybrids.
I went on more service calls to diagnose poor corn yields this fall than any year prior. There’s 3 major things we’re looking for to diagnose problems at this time. 1) Harvestable ear count (not plant count) as some of the ears above we would not consider a harvestable ear. 2) Consistency of ear height. 3) Ear girth or number of rows around. #2 and 3 are determined very early in a corn plants life—V3-V4 to be exact.
We experienced way too many fields with only 12 and 14 round ear girths and far too many fields that the dominant ear height varied by 2.5-3 feet. These are both issues that tell us the problem started very early—again V3-V4. Also keep in mind that in corn, once yield is lost, it’s gone forever.