Spudman March 2023 - 14

Andrew McKenzie-Gopsill in the field using a sandblaster for weed control.
nontoxic also means that this new weed
management option could avoid a host
of regulatory hurdles.
McKenzie-Gopsill's innovative
weed-blasting trials have just
completed their first year. They've
experimented with four different grits
of both walnut shell and corn cob,
as well as a mix of the two. They're
also looking at the potential of other
additives, such as baking soda, that
would leave a coating on any partially
destroyed leaves and further inhibit
photosynthesis.
The crops are sprayed twice: once at
the standard time when an herbicide
would be applied, and once right before
flowering. Researchers then rate the
results using three metrics: the amount
of post-spray new growth, new disease
development, and total biomass and
seed production.
While it's too early for definitive
results in seed production and the
potential effect on disease, the results
on biomass reduction are already
overwhelmingly positive.
14
Spudman * March 2023
" We are definitely seeing a huge
reduction in biomass, " said McKenzieGopsill.
" We were able to get pretty
good control of both lambsquarters and
corn spurry, which are two of our most
problematic species in potatoes here. "
Both lambsquarters and corn spurry
are weeds that common rimsulfuron
herbicides, in this case Prism, have little
effect on, which adds benefit to the
sandblasting technique.
Compared to other methods,
sandblasting adds a much smaller
amount of material to the soil it's being
applied to. McKenzie-Gopsill's trial is
targeting a mass of only 480 kilograms
per hectare (roughly 425 lbs/ac), and
so far seems to have little to no effect
on the soil chemistry. Researchers
are watching for any potential effects
caused by the introduction of allergens
that potentially hitch a ride on the
walnut shells, but so far none have been
detected. In the future, there may be a
potential to combine fertilizers with the
projectile material that could increase
soil health while eliminating weeds.
McKenzie-Gopsill hopes that
sandblasting will emerge as one of the
lowest-cost solutions for potato weed
management available. While other
new, high-tech solutions using lasers
and flamethrowers to destroy weeds are
in development and already in use, the
machines required for these techniques
are costly. Sandblasters are inexpensive
and use what would otherwise be
waste material as the medium, so
the technology would be much more
accessible for smaller farms.
It's also more sustainable.
" It could potentially be very useful in
organic production, " said McKenzieGopsill.
" As we move towards consumers
demanding to reduce pesticides, it could
be another great tool for producers in
their weed management tool box. "
McKenzie-Gopsill is excited to see
the full results after the two-year trial
period is completed. If the results
continue to be as positive as the first
year has been, sandblasting has a huge
potential to be a player in potato pest
management in the very near future.
Spudman March 2023

Table of Contents for the Digital Edition of Spudman March 2023
