Research
Robert Di Cristoforo and Dr. Peter F. Sweatman, 03-9334-7888,
peter@woaduser.com.au, Victoria, Australia
In recent years, there has been a significant increase in the
volume of hay moved and an increase in the number of accidents
involving vehicle rollovers or hay falling from trucks. This study,
conducted in Australia, aimed to provide a sound technical basis
to aid in the loading and moving of bales. Tests revealed enormous
variations in lateral rigidity between the different types of
bales, with round bales offering the least rigidity. The 4ft x
4ft x 8ft rectangular bales were by far the best performers, with
more than twice the rigidity of round bales at 4.6m high. Oct.
2003.
Tractor Tire Needs May Vary in No-Till and Conventional Farming
Systems
David Elstein, ARS News Service Agricultural Research Service,
USDA, (301) 504-1654, delstein@ars.usda.gov
Farmers who do not till their land may need different types of
tractor tires in the future to minimize soil compaction, according
to a study by the Agricultural Research Service. Compaction is
caused by the weight of the tractor tires pressing down on the
soil. When operating tractors, farmers try to minimize compaction
because it can hinder infiltration of water to crop roots and
increase soil erosion and water runoff.
Thomas R. Way, an agricultural engineer with ARS's National Soil
Dynamics Laboratory in Auburn, Ala., led the study in cooperation
with Tadashi Kishimoto at the Obihiro University of Agriculture
and Veterinary Medicine in Japan. In the study, the researchers
used a tractor tire equipped with six sensors on its tread to
study tire pressure on tilled and no-till soils. Surprisingly,
they found that the pressure was least uniform on untilled clay
soils, and was actually more uniform on tilled soils. This research
is expected to help manufacturers adjust the tire contact pressure
and the size of tire lugs. The lugs have considerable contact
with the soil and they also can affect compaction. Changing tire
pressure and size could help minimize compaction on no-till fields.
Researchers were also surprised by the similarity of another
factor called "tractive efficiency" on tilled and no-till
soils. This is a measure of the efficiency with which the tire
converts the power that's applied to the wheel to useful work.
A tractor's fuel efficiency increases with its tractive efficiency.
The study showed that tractive efficiency was the same on tilled
and no-till soils, meaning there was actually little difference
in fuel efficiency.
"Sewing" the Soil: A Quicker Way To Measure Soil Compaction
David Elstein, ARS News Service Agricultural Research Service,
USDA, (301) 504-1654, delstein@ars.usda.gov
A new device developed by an Agricultural Research Service scientist
may be the best yet for measuring soil compaction, which causes
problems for farmers by preventing moisture from seeping down
to plant roots. Compacted soil also increases water runoff and
wind erosion.
Agricultural engineer Randy L. Raper of the ARS National Soil
Dynamics Laboratory in Auburn, Ala., has led the development of
technology, in cooperation with Auburn University, that uses one
sensor to measure soil strength at all depths in the top 18 inches
of soil. Raper's invention is known as OMIS (for On-the-fly Mechanical
Impedance Sensor).
OMIS isn't the first device developed to measure soil compaction.
Scientists have developed and tested several others, but those
only measured soil at a few depths. Often this isn't sufficient
where compaction varies throughout each field and may be caused
by a thin hardpan. Hardpan is a dense layer of soil that restricts
root growth and the movement of moisture, air and beneficial organisms
through the soil. So farmers need to check compaction at various
soil depths, not just the few that other devices measure. Raper’s
invention consists of a sensor attached to the front of a shank.
As the shank is pulled by a tractor through the field, it is moved
up and down like a needle on a sewing machine. As the tractor
moves forward, the sensor is cycled up and down to measure the
soil strength.
Farmers can use Global Positioning System technology to create
soil compaction maps and adjust their tillage depths. OMIS could
also be customized to measure other properties, such as electrical
conductivity and the amount of moisture in the soil. Raper is
continuing to improve the technology for field use and hopes the
new invention will be on the market in a few years. A patent application
has been filed, and ARS is looking for a licensee to commercialize
the device.
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