An Easier Way to Measure Soil
Compaction? By David Elstein
March 3, 2003
Measuring soil compaction may soon be easier for farmers,
according to Agricultural Research
Service scientists who are evaluating a new sensor that attaches to a
tractor and measures compaction at six different depths as it moves across a
Researchers at the ARS
Cropping Systems and Water Quality
Research Unit in Columbia, Mo., led by agricultural engineer Kenneth A.
Sudduth, have designed and are evaluating the sensor.
Compaction is a key factor in soil productivity. Soil has many
properties that determine its value for crop production. For roots to thrive,
the soil must provide the right amount of water, as well as have good texture
and the correct amount of nutrients. The level of soil compaction is equally
important. If the soil is too compacted, there will not be enough pores for the
roots to respire properly. If the soil is too loose, nutrients will leach
through the root zone too rapidly and will not be useful to the plant.
Soil compaction is primarily caused by farm equipment traffic.
It can vary widely over fields and thus can contribute to different yields in
Researchers and consultants have traditionally used a cone
penetrometer to measure compaction in the field. The instrument is pushed into
the ground to measure compaction at a single location. Using a penetrometer to
map compaction variations within a field requires a lot of effort. To get an
accurate map, the penetrometer data must be collected at many locations.
Scientists and farmers would benefit from the new instrument, which is easier
to use and gets better results.
Maps of compaction measurements will show the farmer where
compaction may be a problem within a field. This new information should also
help to interpret the yield maps which many farmers already use. Understanding
yield variations and the causes for them is an important step toward making
better use of precision agriculture.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.