"Sewing" the Soil: A Quicker Way To Measure
Soil Compaction By
September 29, 2003
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
Dynamics Laboratory in Auburn, Ala., has led the development of
technologyin cooperation with Auburn
Universitythat 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, particularly in the
Southeast, 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
ARS is the U.S. Department of
Agriculture's chief scientific research agency.