HE'S quietly spoken, methodical and passionate.

And at 68 is now retired from farming but the passion lives on.

And it's the reason, after more than 40 years in the game, that former Bruce Rock farmer-turned manufacturer Tom Lewis is still going strong.

A self-confessed tinkerer, Mr Lewis is poised to see the fruition of 30 years of experimenting trying to kill weeds seeds by mechanical means.

"I've found 10 ways you can't do it but I think, now, as a dedicated team we've finally done it," Mr Lewis said, describing Tecfarm's new header-ready WeedHOG mill which will be marketed and sold under his company's Tecfarm banner.

"While the well-known cage mills kill weed seeds very well, we believe we've got a viable alternative to complement the market and our design has patents-pending in Australia, Canada, the United States, European Union and United Kingdom.

"With a limited run this year, full commercial production is planned for next year and we've generated plenty of interest among farmers."

Mr Lewis is undaunted at the prospect of competing with established competitors, "who have excellent products".

"We haven't gone into this just hoping," Mr Lewis said.

"We believe we have a built-for-purpose tool that can improve the bottom line of cropping operations by significantly reducing weed seed banks in a very cost effective way."

Mr Lewis has achieved it without any grant money or outside funding.

"Tecfarm's Chaff Carts have been the project's main funding source," he said.

All this enthusiasm is buoyed by his "fellow researchers" - wife Denise, son-in-law Matt Barrett-Lennard, son David, who is the technical equipment developer and adviser Neil Brandon, AgTech Innovations director.

"All of us enjoy what we're doing and we're always questioning," Mr Lewis said.

It was that character mix that led to the formal research and development of the WeedHOG mill four years ago.

Weeds became a major blip on Mr Lewis' radar after his farming family sold their sheep in 1981 and began continuous cropping.

"By late 1980s we started encountering chemical resistance problems using chlorsulfuron on ryegrass," he said.

"And as resistance levels rose in the 1990s, integrated weed management became a sort of buzzword so we used chaff carts to manage weed seeds in chaff residues.

"Overseas-designed carts were effective to the extent you could see chaff windrows disappearing but they had mechanical problems,'' he said.

"We started Tecfarm in 2009 and initially we developed liquid fertiliser carts, having been a pioneer user of UAN since 2000.

"But it wasn't long before we had farmers asking us if we could build them a chaff cart.

"We grew the business with chaff carts and still build them, but it was fairly clear to us that the emergence of a mechanical system to control weed seeds was going to gain traction for a big part of the agriculture market world-wide."

While rivals focused on seed kill rates of more than 90 per cent, Mr Lewis took a thoughtful view based on his experience and set design parameters that included simplicity, reliability, lower horsepower draw and lower cost.

"It seems to us, more work is needed studying weed kill variability with crop conditions, wear rates, etc and this will become clearer over time," he said.

"Realistically, weed seed kill rates seem to vary between 70 and 90pc when it comes to annual ryegrass and a lot depends on chaff flow going through the mill.

"Researchers have told us we need to put three kilograms a second of chaff through the mill, but that's a lot of chaff encountered mainly in higher-yielding crops.

"We knew most Wheatbelt crops would average between 1.5 tonnes a hectare and 3t/ha and we have measured a really good direct kill rate, averaging 80pc in such crops.

"Two years of trials have shown us that when chaff levels are very high, the WeedHOGs' capacity is high but kill rates are at the lower end.

"So we studied chaff flow and where the majority of weed seeds were located in that flow.

"Using vertically orientated capture bags we found that more than 80pc of weed seeds exiting over the sieves were in a range of less than 30 centimetres above the chaffer sieve.

"This led us to control the inlet baffle to direct chaff flow above or below the baffle which reduced excessive chaff entering the mill and the chaff that did enter below the baffle contained the most weed seeds.

"We're looking at an automated process for this."

But according to Mr Lewis an exciting development is the observed environmental effects of seeds escaping the mill, albeit, damaged.

"We've started multiple trials to practically study the effect of weathering and pathogenic attack on partially damaged seeds or breaking of their dormancy," he said.

"These trials will be ongoing.

"It's a phenomenon that has been documented for decades by several overseas scientists working with a number of weed species very similar to annual ryegrass.

"Ryegrass is so genetically adaptable and can lay dormant for years.

"If dormancy is broken the obvious conclusion is that those seeds can be controlled as well.

"So it backs our belief, that it is not necessary to expend large amounts of power, achieving a high percentage direct kill at harvest.

"The environmental effect is sort of free"

A benefit of the WeedHOG's design is that it will be compatible to headers that do not have the horsepower to fit competitive brands.

"Aftermarket chipping or remapping harvester engines to increase horsepower to cater for cage mill models may be unnecessary with the WeedHOG requiring much lower power input," Mr Lewis said.

"We also believe with the WeedHOG you can make a big impression in reducing weed seed bank numbers and eliminate volunteer carryover into next season's crops."

Tecfarm will continue providing chaff carts "because they can clean up crops marvellously while giving mixed farms free summer stock feed".

Mr Lewis said his take-home story was to employ the most cost-effective harvest weed seed control for your individual farming enterprise.

"No two farms are the same and there are now a number of tools to use," he said.

"It's exciting times."