Guidance systems open new doors
By Helen McMenamin
The stress level just drops...
While guidance systems ease the stress of field-work seasons, they also allow
for closer equipment monitoring and open the doors to practical site-specific
"I'd sell the farm before I'd part with it," John Wright says of
his GPS guided auto-steer system. The Swift Current farmer bought a basic lightbar
guidance and simple mapping system for the 2003 season and upgraded to an auto-steer
system two years later. He now has two systems that he moves from drill to sprayer
"The stress level just drops," says Wright. "It leaves me free
to put my full attention on the equipment: header, sprayer booms, whatever.
Plus, I can link it to the combine yield monitor and map exact yield data."
Lightbar guidance helps a grower stay on track, but not everyone finds them
easy to use. Its mapping function is basic: field shape and track driven. That
is a useful record for custom work, but not a planning tool. After using a lightbar
for a couple of years, Wright chose a Trimble GPS auto-steer system that clamps
on to the steering wheel of a tractor or combine. It takes him just a few minutes
to move it from one machine to another.
Once he has lined up the implement, he does not touch the steering wheel except
to steer the first pass around obstacles and to turn at the ends of the field
when he is working back and forth.
Many people find a guidance system worthwhile because they are not as tired
at the end of the day. Part of Wright's reason for buying the auto-steer was
to have the option of having an inexperienced operator run the seeder. He also
has linked his guidance system to the combine's yield monitors, logging yield
every second. Despite claiming he is 'computer illiterate and staying that way',
he adjusted the system to correct for the 14 to 20 seconds it takes for grain
to travel from the cutterbar to the sensor that weighs clean grain.
"You travel a long way in 20 seconds at five to eight miles an hour,"
(more than 50 yards) he says. "It's not hard to program the system so we
know exactly what each area of the field is contributing to the yield."
Combining the yield map, topographic and soil maps for his fields, Wright can
see exactly what part of a field yields most. "It absolutely amazes you
to see where your yields are really achieved," he says.
In 2007, Wright plans to field-test variable fertilizer rates in a replicated
strip trial. He will apply both a nitrogen-sulphur blend and a phosphate-potash
blend to match the needs of four or five production zones, figured from benchmark
soil sampling sites. Then, he will combine on the diagonal and assess returns
from the centre of each three-drill wide strip.
For anyone looking at GPS systems, Wright advises buying a system that can
be upgraded. "Think what you could possibly be doing in the future,"
he says. "If you'd told me five years ago, I'd be doing site-specific farming,
I'd have said you're nuts, but this technology is amazing. You might be surprised
how you use it."
One thing Wright has not found is any savings on inputs. "We set our overlaps
to six inches for combining, 12 inches for spraying and zero for seeding,"
he says. "But, I haven't seen any input savings. I know the acreage a tank
of product covers and that's what it does. With the auto-steer, I can do a better
job, all the tracks are perfectly straight with no misses or over-application."
As a partner in AccuTrak, University of Regina professor of electrical engineering,
Ron Palmer, is quite dissatisfied with GPS and guidance systems. "GPS was
designed by the military to aim bombs, not to manoeuvre around plants,"
he says. "And, it's available and free right now, but at any time the US
military could pull the plug."
Also, current equipment, with its long seeding trains exaggerate the inefficiency
of turns, as it takes an operator some distance to line up for each pass. In
a turn, the inside end of the equipment is stopped while the outside is travelling
twice as fast as the centre, changing application rates and, often, row spacings,
so some plants are over-crowded and others over-spaced.
"We're getting bigger, not better equipment," says Palmer. "An
old- fashioned press drill, where every gang was ground-driven, seeded a crop
more uniformly than an air-seeder where a short turn makes extreme variation
and an obstacle causes real problems."
Palmer's answer is smaller, automated equipment that attaches directly to the
tractor so it is pulled straight, as it is designed to be. The equipment can
take the most efficient track through each field, with no overlap and no steering
slop. It can even be programmed to avoid the last round that is a few feet wide.
Altogether it cuts driving and inputs by 25 percent. "Small, automated
equipment is the biggest bang for the buck in farming," says Palmer. "For
efficiency, we have bigger farms seeding with a single outfit. But that puts
the operation at a huge risk. Any breakdown or bad weather is a huge problem.
"Everything depends on that one piece of equipment. Several small pieces
of equipment cut the risk to the whole enterprise: you can still run at 80 percent
if one of five seeding outfits has a breakdown. But to be feasible, the machines
have to be automated."
Automated equipment is feasible
Palmer demonstrated automatic seeding 20 years ago. All that is missing is a
really accurate positioning system. AccuTrak is developing an accurate, reliable
system a farmer would take to the field and position near it for that operation.
Instead of satellites, it will use reference beacons that fit in a container
the size of a lunch bucket.
"It would change the whole way we farm," says Palmer. "Farmers
could become true managers rather than drivers of heavy equipment."
Changes in equipment would also be likely. Drills drag soil around, a new type
of seeder might punch in seed and fertilizer, like a sewing machine, allowing
precision-seeding for cereals. Weed control could be refined too, maybe with
a water-knife. The changes Palmer envisions are revolutionary, but the first
step, he says, is to get the farmer off the tractor and that requires accurate
The cost of obstacles
Obstacles, whether sloughs, trees or well-heads, are a problem whether equipment
is operated by a human or it is automated. They make field-work much less efficient,
and the larger the equipment the bigger the impact of an obstacle.
According to Palmer, three obstacles, say two sloughs and a little bush, in
a quarter section increases the theoretical distance driven (the most efficient
track to cover the field) with a 62 foot sprayer from 34 to 43 kilometres. In
real life, overlaps add 10 percent and another 10 to 15 percent for less than
perfect turns, which are emphasized by obstacles, and the tracks are 41 kilometres
for a clear quarter and 54 kilometres with the obstacles.
Natural obstacles have benefits as well as costs, but the loss of field efficiency
applies to obstacles like oil wells too. -30-
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