Farmers struggling with herbicide-resistant weeds may soon be looking at a mechanical option for relief.
A machine invented by Australian farmer Ray Harrington is getting a look by scientists in the United States. The Harrington Seed Destructor (HSD) pulverizes small weed seeds, rendering them unable to germinate.
University of Illinois weed scientist Adam Davis is among a handful of investigators involved in a nationwide study of the machine’s weed-fighting ability. The U of I campus in Champaign is among three locations participating in a USDA Agricultural Research Service project. The others are in Maryland and Arkansas.
Davis sees potential in the machine, though he doesn’t view it as a single solution.
“I don’t think it will be a game-changer by itself,” he said. “It will contribute to a much more effective integrated weed management strategy. When used with other tactics, it will take a lot more pressure off other tools.”
The HSD can be pulled behind a combine. It reroutes smaller bits of the chaff, and crushes small seeds mixed in. It has been shown to be effective crushing the most troublesome weed seeds, such as waterhemp and palmer amaranth.
The machine must be specially fitted to attach to each combine, which can be a time-consuming process. It took a U of I fabricator about six weeks to adapt it.
“Every combine has a slightly different materials flow, so you have to customize your combine to work with the HSD,” Davis said. “Ray Harrington is using it in wheat fields. This is the first time it’s been used in soybean and cornfields. We’re learning a lot about it as we go.”
Besides the trouble of attaching it, the cost of the pull-along model would likely make it impractical as an on-farm purchase. However, the engineering company that bought rights to the machine has developed an integrated version that may be available next year.
That adapted version can be bolted onto the combine itself, negating the need for a separate, bulky machine that trails behind the combine. And the estimated price difference is substantial: about $30,000 for the integrated model vs. $180,000 for the pull-behind machine.
“The tow-behind model is almost as big as the combine itself. The integrated version is a much smaller device,” Davis said. “You’re intercepting the chaff flow and then running it through an integrated cage mill.
“I believe that the pull-behind model is too much of a hassle and too expensive for growers to do themselves. But the integrated version should be at a price point that individuals can afford. We see equipment companies offering that as option.”
Davis noted harvest testing done at the U of I campus recently was smooth. The combine pulling a self-propelled seed destructor was able to operate at full speed.
“We had some fields full of waterhemp and no problem passing through that,” he said.
Researchers have all the seeds collected, and will spend the winter looking at the number of seeds and how much they were damaged. They will then spread the seeds over the field and allow them to over-winter as normal seeds would.
The research at Urbana included comparisons between different herbicide treatments and tillage types, no-till and chisel plow.
Last winter the team tested different weed species in stationary test. Seed sizes ranged from very small (waterhemp) to large (cocklebur and giant ragweed). The machine proved to be effective on more than 99 percent of the seeds.
“We’re looking at efficacy of the HSD, but that’s only a part of the objective,” Davis said.
The testing will continue for five years.
“For growers who are interested in this technology, it’s important for them to think beyond silver bullets,” Davis said. “HSD could be important part of solving some of these problems.”