Jeff Phillips got a call to check a corn field. That's not unusual. Phillips is the long-time Extension ag educator in Tippecanoe County, and former head of the Purdue University soil testing lab, which no longer operates.
I went along with him. The field had a few spots with yellow corn as we drove up. Most of it looked ok, though, and the corn was tasseling and silking. It wasn't until we walked into the field a ways that we figured out every so often there were two somewhat shorter, more yellow rows. We checked the pattern- it was about every 12 rows. However, sometimes the rows turned back to normal down the field a ways.
The farmer said it was the second year in a row he had noticed strips of yellow corn, actually running the opposite direction of planting across the field. Phillips confirmed it by waking the field. Scouts call it ground truthing. Again, the strips didn't go all the way through. They were hit and miss.
Phillips agreed this was the perfect situation to have access to one of the new unmanned aerial vehicles. From 300 to 400 feet, it would have been possible to get a view of the field and see if there was indeed a pattern. One can only walk through so much 7-foot tall, pollinating corn, even on a cool July day.
Access to aerial satellite of fixed-wing plane images, regular or in infra-red, would also have helped. Unfortunately he didn't have access to either.
Phillips intends to attack it by taking soil samples in the yellow spots and the green spots. Since it's showed up two years in a row, there's obviously a cause. The yellow is likely due to less nitrogen in the plants, although other factors could be at work, he says. Whether it's soil compaction, a problem with an applicator or something else, he says he can't tell until he gets more information.
Stay tuned – we'll let you know.