February 2019 - 20

Not
So Fast
While technology is coming, don't expect drones
to quickly reinvent agriculture
By Zeke Jennings
MANAGING EDITOR
This is the first story in a series called
Grow Ahead, in which Spudman will
explore emerging technologies impacting
specialty crop operations.
T
he premise that drones will change
the landscape of agriculture has
been around for several years
now. As recently as 2016, the MIT
Technology Review said drone usage
was " revolutionizing " farming.
While drones in the field - whether
for crop monitoring or spraying - is
on the rise, the hype machine seems to
have slowed. Drone usage is a part of
farming's future, but suggesting drones
will
reinvent
agricultural
probably
borders on being hyperbole.
" Drones won't take the place of
airplanes, but they will find a place in
pesticide application, " Dominic LaJoie,
vice president of environmental affairs,
National Potato Council, said during the
recent Potato Expo in Austin, Texas.
Pesticide and herbicide application
is becoming more feasible, but - like
most other uses researchers see for
drones - not to the point of being
readily available for growers. Ian
MacRae,
professor
and
Extension
entomologist, University of Minnesota,
who has done extensive research using
drones, spoke on the subject during
the Great Lakes Expo in Grand Rapids,
Michigan, in December 2018.
20
Spudman.com
In terms of spray application, MacRae
said affordable drones can only carry
about 10 pounds of product at a time,
which hardly makes them efficient for
large fields.
" It's really not for conventional
application yet, " he said.
Here is what MacRae had to say
on a variety of topics involving drone
technology.
REMOTE SENSING
" What's driving this whole idea
behind drones and remote sensing is
the advances in technology, " MacRae
said. " Although the drones are getting a
lot of attention, the drone is really just
a flying tripod. The real story comes
with the sensors. Like with cell phones,
everything gets smaller, quicker, better
and cheaper. That's what's
happening with sensors. "
For example, MacRae
said a four-sensor
device that measures
wavelengths to detect
unhealthy plant activity
that ran for about $8,000
just a few years ago is
roughly half that today.
THERMAL CAMERAS
The way remote sensory technology
works is by sending multiple wavelengths
toward the plant and monitoring what's
reflected back. The most telltale is near
infrared light, MacRae said. A reduced
amount of reflected infrared light is a
sign of a stressed plant, but that isn't a
new finding. Where the advancement is
happening is in the use of temperaturesensitive
cameras.
" Quite frequently, with insects and
diseases, the impact that they will have
is both will sit on the same wavelength, "
MacRae said. " But diseases, theoretically,
interrupt the plant's thermal regulation
more than insects. So we can use the
thermal to sort out whether we're
dealing with an insect or a disease.
" These thermal sensors are so small,
we can actually mound them on a drone
at the same time as the other sensors. "
High-Tech Tools
2019
DEPENDABILITY
The cost of the drones themselves
is coming down, along with sensory
equipment and cameras, but it's still a
fine line on balancing investment with
risk. As MacRae said, if you fly a
drone, that drone will crash at
some point.
" There is a lot of variety out
there. You can go for a large
one. We fly those, but we also
start to segue over to smaller, less
expensive vehicles, " MacRae said.
" The rationale for that is when one of
these things crashes - you notice I didn't
say 'if' - but when it crashes, you're out
a lot less money. The DJI S1000, they're
about $4,000. The 3DR Solos are about
$300. They function the same way, and
they're about as reliable. The difference
is the S1000 is a much heavier payload,
so we use it for much larger sensors. "
http://www.Spudman.com
February 2019

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