Meet the Weed Seed Pulverizing Machine
O n a cold , clear day last November, a combine lumbered through a soybean field in Beltsville, Maryland, towing a bulky-looking gray and red machine like a caboose. With each pass, the combine separated the beans from their hulls and then directed plant waste into the smaller contraption, which pulverized the chaff and then shot it back onto the field in a steady stream of dust.
The roar from the farming equipment was deafening — like standing on a busy airfield — and Steven Mirsky, a talkative ecologist with the United States Department of Agriculture, shouted inaudibly over the din.
Steven Mirsky, an ecologist with the USDA, has sought practical solutions to the weed paradox for more than a decade.
Visual: Annie Klodd
Known by a name seemingly out of a superhero comic book, the Harrington Seed Destructor is a mechanical beast that takes aim at a tiny but formidable enemy: the seeds from crop-destroying weeds. They plague farmers the world over, and left unchecked, weeds would cost an estimated $43 billion in lost soy and corn production alone in the United States and Canada each year.
To fight back, most farmers have two main choices, at least for now: rip the weeds from the ground by hand or by plow, or spray them with chemical herbicides so they wither and die. But these choices have long presented a paradox. Tilling can control weeds, but it also can disrupt and degrade the soil — and poor soil grows poor crops. Herbicides, on the other hand, are easier to use — just point and spray — and they can preserve the soil’s delicate structure. But just like bacteria exposed to too many antibiotics, weeds confronted by years of herbicide spraying can give rise to resistant varieties that are increasingly hard and expensive to kill.
Today, in fact, there are more than 250 species of weed that are resistant to at least one key herbicide ingredient on the market, according to the International Survey of Herbicide Resistant Weeds, a coalition of weed scientists in over 80 countries. And according to data from the U.S. Environmental Protection Agency, companies don’t have many new herbicides in development.
That’s where Mirsky and the Harrington Seed Destructor, or HSD for short, come in. Mirsky — who manages around 100 acres at the USDA’s Agricultural Research Service station in Beltsville, and whose bubbling energy seems perpetually stuck on 11 — has sought practical solutions to the weed paradox for more than a decade. One of his goals is to go after the seeds, when weed populations are especially vulnerable, rather than trying to control weeds that have already taken root. The approach “has been kind of a dream for the weed science community,” he says.
But weed seeds are wily — some plants can produce hundreds of thousands, which spread quickly across a field. Until recently, there hasn’t been a machine that’s been able to tackle weed seeds on a large scale, where farms with “five, ten thousand acres could go, not blink an eye, hit their fields and keep on going,” Mirsky says.
In 2014, at the annual Weed Science Society of America conference in Vancouver, Canada, Mirsky saw a group led by Australian scientists present research on the HSD, which smashes the delicate reproductive machinery inside of weed seeds to leave them impotent. “Wow! This awesome!” he remembers thinking. “This is what we need to be doing.”
Of course, no machine will solve all of farmers’ weed woes, and taming the pests and plagues that threaten our food takes a diverse set of tools. But Mirsky and his team — which includes Adam Davis, a USDA weed ecologist in Urbana, Illinois, and Jason Norsworthy, a weed scientist at the University of Arkansas — do see the HSD as the cornerstone of an ambitious five-year project that spans 17 research centers in 13 states. Instead of emphasizing chemical spraying alone, the researchers want to use a multi-faceted approach, termed by weed ecologists Matt Liebman and Eric Gallandt as “many little hammers.” Success will mean not just finding the best suite of tools to kill the weeds, but also convincing farmers to change their habits.
“Every farmer needs to be thinking about how to do this now,” Davis says. “There is no path forward for chemical-alone weed management. We have to reduce our reliance on herbicides because there’s nothing new in the pipeline.”
The newest version of the Harrington Seed Destructor is now getting attention from farmers worldwide. And if the machine can effectively chomp the seeds of the right species of weeds; if enough farmers incorporate weed seed control into their land management plans; and if a tempting new chemical doesn’t come along to start the herbicide cycle anew — then the HSD just might work.
F armers have been tussling with herbicide resistant weeds for at least 60 years. The first widely used synthetic auxin herbicides, which mimic plant growth hormones, appeared in the 1940s. By 1957, farmers in Hawaii found auxin-resistant dayflowers creeping into the sugarcane, and Canadian fields broke out with auxin-resistant wild carrots.
The reason is simple and inevitable: evolution. Herbicides put an artificial selection on weeds, and the more farmers use the chemicals, the higher the pressure for the plants to evolve. Herbicides don’t necessarily kill every weed in a field. Some have the genetic constitution to survive and spread their vigor to a new generation.
But in some regions, resistance has run amok. This is particularly true for the herbicide glyphosate, the main ingredient in the product Roundup. Monsanto launched the chemical in 1974. Twenty years later, the agricultural company introduced its first glyphosate-tolerant GMO seeds, which it genetically engineered to make crops immune to the herbicide. These “Roundup Ready” seeds allow farmers to spray glyphosate on corn, soy, and cotton to kill weeds without worrying about killing the crops in the process — a faster, easier approach that also leaves the topsoil intact.
In 1994, Farm Chemicals magazine proclaimed the herbicide among the “top ten products that changed the face of agriculture.”
Critics have pushed back against herbicide-tolerant GMOs and glyphosate over the years. Some concerns are environmental, such as the increase in glyphosate use that has led to more resistant weeds. Others are over health, particularly of farm workers who have regular exposure to the chemicals, although the science is mixed and highly politicized. Still, the seeds remain popular. In 2016 in the U.S., they made up 94 percent of soybeans, 89 percent of cotton, and 89 percent of corn.
But the seeds’ popularity have contributed to glyphosate’s downfall. Fans of the technology rightly point out that GMOs aren’t directly responsible: Genetic engineering itself doesn’t drive resistance. But widespread use has led to an over-reliance on glyphosate. “Wow, why are we in this situation?” Mirsky says. “Well, one of the most Cadillac practices that we’ve developed, that is the most important [soil] conservation strategy of our time — no-till agriculture — is a big part of why we are seeing this resistance.”
▲ Weeds like waterhemp, a type of pigweed, are a major problem for farmers, and most varieties are resistant to at least one common class of herbicides. Visual: Bill Curran
New ‘Terminator’ to destroy weed seeds
The Seed Terminator in action, destroying more than 90 per cent of weed seeds during harvest.
SOUTH Australian company Seed Terminator Pty Ltd is setting up a Western Australian dealer network this week to sell and support its new seed destruction machine.
Called the Seed Terminator, it will be a direct competitor with the Integrated Harrington Seed Destructor, distributed nationally by McIntosh & Son.
But Seed Terminator director Mark Ashenden said the unit was new technology (two patents pending supported by an international legal “freedom to operate” opinion) and met a price point under $100,000.
“It will be an integrated unit designed to fit all colour combine harvesters starting at Class 7 and incorporating Class 8 and 9,” he said.
“Our whole premise in developing the Seed Terminator was that it would be colour blind and meet a more than competitive price point in the market.
“We have achieved those things and we have been swamped by farmers wanting a unit for this harvest.
“We plan to make 2017 a limited release year and our call for expressions of interest has all but shut the gate on further production.
“But we are gearing for full commercial production for the 2018 harvest and we are confident we will have a strong dealer network in place in WA to provide full product back-up.”
According to Mr Ashenden, the Seed Terminator provides a simple one-pass solution to harvest weed seed control.
Weed and volunteer seeds present in the chaff material leaving the cleaning shoe are intercepted and pulverised using a new multi-stage hammermill technology.
It incorporates an efficient mechanical drive system that is driven by the harvester engine, with minimal moving parts, incorporating only shafts, belts and gearboxes.
“It is highly efficient with minimal transmission losses,” Mr Ashenden said.
“The hammermill technology incorporates trade-marked Aero-IMPACT technology, for efficient low turbulence aerodynamic impact.
“The Aero-IMPACT provides the impact needed to kill more than 90 per cent of annual ryegrass seed (as tested by the University of Adelaide) while maintaining a low power draw.”
The mechanical drive system incorporates Smooth-Feed trademark technology to prevent material blockages.
“The power draw with the combination of the hammermill and mechanical drive system is low enough to allow for attachment to Class 7 harvesters,” Mr Ashenden said.
“This technology is only the beginning for Seed Terminator because we will continue to invest heavily in research and development to continue to provide better solutions to grain producers.”
Last harvest the company trialled nine prototype units installed on Case (7120, 8010, 8120, 9240), New Holland (CR 8090, CR 9090) and John Deere (9760 STS, 2 x S680) headers.
The prototypes were trialled in WA, South Australia, New South Wales and Victoria across a variety of crops (wheat, barley, canola, lupins, oats, lentils, faba beans), soil types and key rainfall zones.
Additionally, a special project is underway to fit-up and operate the Seed Terminator on a CLAAS Lexion harvester and to investigate an option for Massey Ferguson.
The R&D plan for 2018 includes setting up multiple test-stands to proof and test settings for efficiently killing a wide range of weeds in different crop types; robustness testing of the drive and all components; robustness testing of the mill; using a torque transducer to test and measure the power draw.
“This program is an example of our commitment to improve the farmer outcomes and the value of the Seed Terminator,’’ Mr Ashenden said.
Mr Ashenden, who has extensive banking and accounting experience and holds an MBA, said the idea of the Seed Terminator came from his nephew, Kangaroo Island farmer Nick Berry, who after completing an engineering degree published a PhD on eliminating weed seeds.
“Nick came up with the technology and I assisted with gaining private funds to get the concept off the ground,” Mr Ashenden said.
“Now we are ready to take it to the market and WA will be a major market for us.