The concern in late September one year ago was whether cornfields would reach physiological maturity before frost. Late planting and average to cool temperatures during summer 2019 meant even midseason hybrids that usually reach black layer in September weren’t yet at that stage by Oct. 1.
In fact, in the Corn Watch field one year ago, one hybrid reached black layer during the first week of October. The second hybrid didn’t reach the mature stage until mid-October. “That’s a concern when corn matures that late, for two reasons,” says Dave Nanda, director of genetics for Seed Genetics Direct. Seed Genetics Direct sponsors Corn Watch ’20.
First, if a killing frost occurs before corn reaches black layer, it can impact test weight and yield, he says. As it turns out, the first killing frost came at average or later-than-average dates in most of Indiana last year, and most fields still beat frost.
Second, if hybrids are delayed in reaching maturity, there is less suitable time left for moisture reduction and drying in the field, Nanda says. Most corn was harvested at higher moisture content than normal in 2019. That not only increased drying costs, but also resulted in more mechanical damage and fines winding up in grain bins. That leads to more storage issues.
Indeed, grain storage experts reported that incidents of spoiled grain and grain entrapment accidents started surfacing in January, at least two months ahead of when problems typically arise.
Based on what Nanda found in the Corn Watch ’20 field in early September, it’s a different ballgame this year. He broke ears from the two hybrids in the field in half and checked for the black layer on several kernels from each ear.
“I split kernels lengthwise and looked at the tips,” Nanda explains. “In the hybrid that was slightly earlier maturing, there was a definite brown to black layer forming at the tips of kernels. In the other hybrid, it was just ready to form. So, the black layer formed about a month to six weeks earlier this year versus last year.”
The planting date was May 13 this year versus May 27 in 2019. “The other big factor was heat units,” Nanda says. “We had warmer weather overall at the site this year versus a year ago, especially during late August and into September.”
When the black layer forms, sugars and starch can no longer enter kernels, Nanda explains. Drydown is underway at that point. Warmer weather increases drydown rate, and the odds of getting warmer days is much higher in the second half of September versus the first or second half of October.
“I would expect farmers to harvest much lower-moisture corn compared to a year ago,” Nanda says. “Each grower will have to decide the right moisture level to start shelling corn in their operation.”