If you are the designated grain cart driver, you likely had a busy fall in 2017, especially during corn harvest. Indiana’s record corn yield meant many fields averaged more than 200 bushels per acre. Some yielded considerably above that, keeping grain cart drivers busy catching corn from full combine hoppers on the go.
In southeast Indiana, Joel Wahlman, superintendent at the Southeast Purdue Agricultural Center near Butlerville, believes cool nighttime temperatures during grain fill, extending into September, helped plants pack as much energy as possible into kernels.
“Even at mid-August, it was hard to estimate what kind of yields we would have here because corn was planted into June, and there was a long stretch to go yet before corn reached black layer,” he says. “As it turned out, we had ample moisture and cool nights, for the most part. If it’s too warm at night, plants spend part of their energy cooling themselves down. If it’s cool already, that is more energy they can use to fill kernels.
“Most ears were filled with kernels clear to the tip,” he says. “The grain fill period in this part of the state seemed to really help boost yields.
Dave Nanda, Indianapolis, an independent crops consultant, watched the Corn Watch ’17 field all year long. A dry spell from early through mid-August left him concerned about how many tip kernels might abort and how grain fill would turn out. Then it rained near the end of August, and temperatures cooled off.
“Corn plants held on much better and didn’t finish turning brown or die as quickly as I first thought they might, once the weather returned to cooler temperatures with some timely rains,” he says. “I believe many kernels which might have aborted were salvaged, and the Corn Watch ’17 field still made over 200 bushels per acre. Many ears were filled pretty well to the tip.”
Nanda began examining the state of maturity on ears in the field near the end of August. There were two hybrids planted side by side, and one hybrid was slightly ahead of the other with regards to maturity. One also had deeper kernels, while the other had more rows of kernels per ear.
Once it began raining again and the weather cooled, it took both hybrids slightly longer to reach black layer than Nanda originally thought it would, he notes.
Checking for black layer is an easy process, Nanda says. He uses a pocketknife to carefully peel back tissue from the end of the kernel. If a black layer is present, then the corn is physiologically mature, he says. No more starch can enter kernels at that point. Moisture is usually in the mid-30% range, with the actual percent varying somewhat with hybrid.
Until the black layer forms, the plant can still pump energy into the kernel. That happened frequently in 2017, he concludes.