GENESEO, Ill. — The spotty rains throughout the growing season highlight the importance of using a package of diverse hybrids and the need to interpret performance across a wide area, not just a single plot.
Brent Tharp, Wyffels technical product manager, and Ryan Gentle, Wyffels agronomy manager, discussed in a podcast hybrid evaluations, prioritizing fields for harvest, and what they’re seeing in their travels across Illinois, Iowa and Wisconsin.
Gentle said some corn harvesting began in the Springfield and Jacksonville areas right after the Farm Progress Show.
“It sounds like a lot of 220s, 230s. Several of those fields were probably would have been in the 240s, 250s last year and I’m hearing a lot of 10%, 15% off of maybe where I was last year,” Gentile said.
Moisture in that area was around 26% to 32% in early September.
“I’ve been hearing a lot from guys that probably need to get ready, get out and sample some ears because the corn appears to be a little dryer when you actually do the moisture sample than what it looks like from the 60-mph scouting from the road.,” Gentle added.
“There wasn’t a lot of disease late, so there were a lot of fields that the health was good. It’s holding on some green and maybe a little deceptive on how far along that corn is as far as black layer moisture.”
During the week of Sept. 10-16, Tharp traveled through northern Illinois, southern Wisconsin, and into northern Iowa where the corn will be ready for harvest sooner than normal.
“They definitely need to get ready to harvest because it’s going to be here before we know it. In fact, they probably should be starting any time in some of those fields,” Tharp noted.
“As I traveled west, the crop in northeast Iowa, north-central Iowa, is pretty brown. They did not catch any of the August rains to speak of and it took its toll on the crop. Along those lines, I would say the way this crop finished, whenever a crop finishes that fast it cannibalized itself to finish.
“We actually have kernel counts in most of the areas I’ve been in. The kernel counts are pretty strong or normal or maybe even better than normal, but it just shut off during the grain-fill period. That’s where we’re going to get our yield loss from because there’s less kernel size.”
Gentle concurred, adding he’s seen “a little fusarium crown rot set in, some premature death, and a little bit of top dieback, as well. So, it’s important to get out and do push tests to look at stalk quality for field harvest priorities.”
Interpreting Results
“One other thing with the droughty conditions that we really need to be thinking about is how do we interpret results and yield results because it’s going to be all over the board. As variable as the rains were this year, even within a township, yields are going to be that variable,” Tharp said.
“If you have at test plot, you’re going to going to get a view of what those hybrids did in those specific conditions but the best way that we need to kind of overcome that variability is just numbers. “Look at yield results over a wide geography. That’s going to be a better indicator of performance going forward versus the plot in your backyard.”
For a more accurate read on hybrids, multiple locations are recommended.
“If you just look at one location, how likely are you to be right? It’s a 50-50 chance. If you jump up to 10 locations, that’s increased to 75%, and 30 locations is 90% accuracy. You’ve got to look at multiple locations to get your average up to be right when you’re looking at a hybrid and yield results,” Gentle noted.
“Rain was so spotty this year. A mile down the road may have caught a half inch in late June and another farm didn’t, and when you’re comparing yield data this fall you really need to look at the weather and that rainfall map because I can just see some huge yield swings. You don’t want to blame a hybrid when it’s really the weather.”
Tharp added that those accuracy statistics are based on normal conditions, and as variability is added, the probabilities become worse.
Stress Timing
When evaluating plots, Gentle noted differences if hybrids flower early or late and compares that to the weather and the timing of plant stress.
“In my opinion, it’s going to be different in different areas depending on when the field was planted, emergence, emergence uniformity across the field, and then when they caught rainfall in relation to flowering and early grain-fill,” Tharp said.
“It’s not a one size fits all. You can play both sides of that to your advantage or disadvantage depending on a lot of conditions. It goes back to we’ve got to look at multiple locations.
“The other thing that I would say is going to effect us in general is the late grain-fill period. That’s what got affected the most. It’s that grain-fill and kernel depth and it’s more of the late grain-fill. We have kernel numbers there but we’re losing a lot in the dent to black layer and we pushed that crop through that phase really fast. So, I think we’re going to see differences in hybrids that maybe have a lot of kernels versus those hybrids that have fewer kernels but they have to get to their yield by kernel size. They’re probably going to be effected more by this later drought versus hybrids that get to yield by kernel number.”
“There’s a lot that happens with that corn plant in that R5 to R6 stage. At beginning dent, we still have 50% of the yield that can be added to that kernel and that plant. So, just a matter of two or three weeks there as we move through that growth stage, there can be a lot happening if it we get under heat and moisture stress, and we’ve had that in a lot of areas,” Gentle added.
“A lot of the ears I’ve been breaking open have good kernel count, 16s to 18s and 20s around, pretty good length, but I’m not seeing the depth in some of those kernels that I would like to see. That might be where we’re seeing the 10% to 15% reduction on some of the early corn that’s been harvested.”
Diverse Package
Tharp said one way to overcome the variability in yield is to plant a package with diversified genetics and hybrids that will respond to different environments.
“When you’re putting together next year’s order, be sure to diversify and plant three or four hybrids or more,” Tharp noted.
“Not just maturity variation, but you also want to look at the hybrid characteristics and see when some of those hybrids make their yield. You don’t want to pick all ones that rely on kernel depth. You want some that rely on kernel number, as well, to help diversity your package,” Gentle added.
Yield Prediction
U.S. yields are expected to average 173.8 bushels per acre, according to USDA’S September estimate. Tharp asked Gentle what his yield guess is based on what he’s seen in the fields.
“This is my opinion, but I could be wrong. I could be right. Driving around there are pockets in Illinois that could be good. There’s pockets that aren’t very good. I think we need to remember back to June to the way some of the corn looked. Some, especially on the hillsides, lighter ground, it was beyond moisture stress. It was about ready to die,” Gentle said.
“This corn has been through a lot. Some of it got frosted. Some of it had the driest June ever. That derecho laid a lot of it completely flat. Some of it’s gooseneck. That took some energy for it to grow back up and new brace roots and stuff.
“I could go on and on on everything that this crop has been through. We were 173 bushels an acre last year (U.S. average). I don’t think we’ve got the crop we had last year. I’m going to say 170.”
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