Long before there were drones for agriculture, even before there were digital cameras and computers, I learned what happens when soybeans are exposed to light 24 hours a day. They never mature properly. Soybeans need a mix of light and darkness to tell them when they are to mature. Without it, they stay in the vegetative stage.

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Green as gourds! This UAV image, on the right, shows the extent of impact on soybean maturity from street lamps along the road. (Photo courtesy of Dennis Bowman)

We farmed near a town and a big patch of soybeans under the streetlight stayed green. They were still green, growing dark green, at harvest. Forty years ago not every farmer understood what affects soybean growth as most do today. It took us a while to figure it out, but we finally discovered it was because the beans were never in the dark. It was a small patch, so we combined around them and never thought that much about it.

Dennis Bowman got a call from farmers in Illinois where the city fathers of a town had decided to run street lights far into the country, apparently preparing for big growth to come. The farmers saw the same thing – the soybeans near and under the street lights stayed green and didn't mature. Only in this case we are talking a two-mile stretch where soybeans were affected several feet out into the field.

Bowman, an Extension agronomist with the University of Illinois, could see the problem from the ground, and knew the cause. The farmers did, too, but they couldn't get town officials to understand that it was a big deal to them.

So they asked Bowman to fly a drone over the area. His aerial image displayed how far into the field soybeans were affected, and how far the affected strip extended down the road, wherever there were street lamps.

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It was another use for UAVs in agriculture that Bowman didn't anticipate when he began working with them a few years ago. He started primarily to use them in crop scouting and plot work.

Presented with the visual evidence, town officials agreed to work with the farmers. They turned the light off on certain nights, and apparently it helped alleviate part of the problem, or at least soften the effect, Bowman says.