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THE
FARMGATE
BREANNE TIDEMANN HOPES A
new method of controlling herbicide-resist-
ant weeds from Australia takes o in Can-
ada before the problem becomes severe.
The method requires the use of the
$120,000 Harrington Seed Destructor
(HSD), a tow-behind machine attached to
a combine that collects weeds and grinds
their seeds at harvest. Tests in Australia
have shown the HSD is able to crush 92 to
98 per cent of weed seeds.
“We’re hoping Canadian producers can
use the Harrington Seed Destructor to
manage weeds before herbicide-resistance
gets really bad,” said Tidemann, a Univer-
sity of Alberta graduate student. “The ma-
chine would be an add-on to conventional
herbicide methods.”
As part of her PhD research, Tidemann
is working with a team of researchers at
Agriculture and Agri-Food Canada (AAFC)
looking at the seed retention of weed
species like volunteer canola, wild oats and
cleavers.
Researchers in Western Canada will test
the machine in fall 2015 after the data on
weed-seed retention is complete, Tide-
mann said.
“It looks like cleavers will be a good fit
because they hold seeds long into harvest,
and produce high in the canopy. Volunteer
canola is a good target. But wild oats seem
to lose their seeds early on before harvest.”
Despite these first findings, more trials
need to be done to be sure the machine is a
good match for Canadian weeds, Tide-
mann added.
Positive Australian results prompted
Canadian researchers to take a closer look.
In fact, 70 per cent of Western Austral-
ian growers are using a harvest weed-seed
system due to high rates of herbicide
resistance, according to Michael Walsh of
the University of Western Australia, who
has worked closely on HSD trials.
High rates of herbicide resistance
developed due to the predominant use of
conservation cropping systems and the
complete reliance on herbicides for weed
control, which delivered high frequencies
of herbicide resistance, Walsh explained.
“Herbicide resistance in the dominant
weed species is expanding at a dramatic
rate,” he said. “There is a need to add
additional weed control options into weed
management programs.”
Herbicide-resistant weeds a ect 40 per
cent of cropland in Canada, according
to estimates from Bob Blackshaw, weed
scientist at AAFC. And herbicide use is a
major method to tackle weed populations,
he added.
“I think it’s important to have new
methods that control weed seeds,” he said.
“We don’t do much to get rid of weed seeds
at harvest, although some farmers use
pre-harvest herbicide applications.”
Methods like tillage, crop rotation
and growing crops that “choke” weeds
are instrumental when controlling weed
populations at other times of the year,
Blackshaw added.
Canadian farmers have largely balked at
the machine’s price tag, but Blackshaw said
the weed-population in Canada has wors-
ened over the last 25 years, meaning new
methods may need to be implemented.
“In the late ’80s and early ’90s, we’d see
wild oats in 10 per cent of the fields we’d
look at. Now, that rate is at 50 per cent,”
Blackshaw explained. “Every year, wild
oat populations get a bit worse, but we still
have some time to establish other methods
of controlling weed seeds on the Prairies.
“We haven’t seen a new herbicide come
to the market in the last 15 to 20 years, and
we can’t continue to rely on new herbicides
to solve the problem. We have to see what
other methods are available.”
Tidemann said it’s incredibly important
to ensure farmers can continue to produce
high-quality, high-yielding crops.
“We’re not in a state right now where
adoption of harvest weed-seed control
practices are absolutely necessary, but we
don’t want to get to that point,” he said.
“By starting the work now we’ll have the
answers for when producers need them to
aid in the management of their weeds.”
HAPPYHARVEST
PRICEYTECHNOLOGYCOULDBENEFITCANADIANFARMERS
Pulled by a combine, theHarrington SeedDestructor grinds weed seeds le over late into harvest.
Photo: de Bruin Engineering
Winter
2015
Grains
West
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