IT was only a matter of time before the famous Harrington Seed Destructor (HSD) was incorporated into a class eight or class nine harvester. And with the help of the Grains Research and Development Corporation (GRDC) it has now been done.
At last week’s Global Herbicide Resistance Challenge Conference GRDC commercial farm technologies manager Paul Meibusch unveiled the corporation’s most recent design - an inbuilt weed seed mill to replace inventor Ray Harrington’s initial cage mill tow-behind machine.
Though it’s commercial release is still some way off, Mr Meibusch told those in the audience Mr Harrington’s original weed “pulveriser”, which took more than a decade to refine and redistributed crushed chaff and weed seed material back into the paddock at harvest, was a large and expensive option.
Commercial costs for the original tow-behind unit were estimated to reach up to $240,000 a machine. But Mr Meibusch said the GRDC and the University of South Australia never threw in the towel when it came to researching ways to improve the seed destructor and make it more accessible and affordable to growers.
“We always knew there had to be a better option,” Mr Meibusch said.
“Pulling a large, expensive machine behind a harvester presents a whole new range of technical issues for farmers to manage during harvest and it’s really not what they’re looking for.
“So we had to go further.”
Mr Meibusch said researchers knew they had to figure out how to process higher volumes of straw using less power, while avoiding blockages and figuring out how to integrate the HSD into the inner workings of a harvester itself.
He outlined a number of research questions which paved the way to the development of the newly inbuilt prototype:
- How did the impact technology actually work?
- How many impacts did the system need to produce to achieve the desired kill result?
- How hard did the impacts need to be to kill the weed seeds?
- What was the optimal level of acceptable kill rate?
- What volume of chaff needed to be processed?
- How did the machine process more chaff volumes using less power?
- How could the mill be integrated it into a harvester itself so that there were less chaff transfer issues from the harvester to the original tow-behind model?
“Phenomenal volumes of straw come out the back end of a class nine harvester which needs to be stringently managed,” Mr Meibusch said. “They throw out 15-20 tonnes of chaff an hour which uses a fair bit of power.”
The final results of the research were tested extensively in January using a Case IH harvester. “Instead of trying to flip the chaff section out the top and push it into a mill like was done using the original cage mill, tow behind machine, the chaff needs to be processed at the back of the harvester right where it comes out so the straw can continue to flow back over and into the spreader itself,” Mr Meibusch said.
“Essentially the system is made up of two very radically different types of mills sitting at the back of the harvester which takes the chaff and weed material straight off the back and into the mill before spreading it straight out the back and into the harvester’s straw stream itself.
“I have to say it is exceptional.
“We pushed the test machine up to well over 30 tonnes an hour and never once did the mill look like it would never cope with the volume coming out the back.
“It spread consistently and we were able to make use of the power supplied by the harvester itself.”
Mr Meibusch said those involved in the project were right on track to deliver a much more grower friendly system that would hopefully be priced accordingly too. But there was at least another year of work needed to sort out some minor “bugs”.
"But we are on track,” he said.
“At this stage it’s a bit early to know exact cost figures.
“The hydraulics needed will be a basic cost we’re not going to be able to get away from but the inbuilt model will still be cheaper than the trail-behind unit.”
Mr Meibusch said the inbuilt model might become commercially available within two years but the tow-behind HSD model would still be available to growers for a number of years before being gradually eliminated from the market.
“The new look internal model is absolutely as effective as the tow-behind model,” he said. “It’s a very exciting time to be involved in weed seed management.”
