Renewable Farming

Kill weeds with intense UV light? Loran Steinlage hopes this concept goes field-scale

The National Cover Crop Summit organized by No-Till Farmer concludes today, but you can still tap into the excellent video presentations by following instructions at this link.

March 16, 2022 By Jerry Carlson  The summit’s leadoff speaker, Loran Steinlage, is well-known here in Northeast Iowa. I’ve visited his farm near the town of West Union. He’s recognized as a vigorous innovator with a passion for sharing ideas on how you can profitably transition into ecologically responsible — and profitable — farming. He has impressed growers by raising 200-bu. organic corn, refined intercropping and relay cropping, and developed implements for farming green.

So when he told cover-crop conference watchers, “I hope ultraviolet light weed control can come to market on a field scale,” I dug a bit deeper into the technology.

Already, UV frequencies have proven up to 98% effective in killing weed seed as a combine chopper blows chaff out of a combine. The attachment, branded the Weed Destroyer, greatly reduces additions to your farm’s weed seed bank if you have to cope with weed escapes.

The research and development firm Global Neighbor markets a hand-held UV weed zapper intended for homeowners who want to control garden and lawn weeds without chemicals. The firm’s website says, “Some wavelengths penetrate deeply into the plant and its root crown to disrupt plant grown mechanisms. Other wavelengths explode chloroplasts to disrupt a plant’s ability to perform photosynthesis.”

Their website shows a model powered with 110-volt AC, and they also make a battery-powered version.

The firm is testing UV light modules for larger areas, with a goal of making a field-scale implement for tasks like cover crop termination and weed wipeout between rows of corn and soybeans.

Loran showed these photos on his cover crop summit presentation:

Developers used a greenhouse test bed of small grain to demonstrate weedkilling power of their UV wavelengths. A light box about 12 inches wide was pulled across the crop in several passes.

A UV “light box” with multiple wavelengths was pulled across this lawn, resulting in complete kill of grass. It’s a demonstration of how light modules could be ganged for broadacre weed control, or arranged to take out weeds between rows.