By Ben
Coxworth
December 23, 2020
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Different
wavelengths of reflected microwaves correspond to different soil colors RUDN
University
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As soil characteristics such as
mineral content, density, salinity, humidity and humus content vary, the color
of the soil varies accordingly. These color variations can be clearly seen in
soil core samples. While handheld tools can be used to extract relatively
shallow samples, more specialized equipment and processes are required for
digging out longer, deeper samples.
Seeking a less labor-intensive
alternative, a team from Russia's RUDN University tried using ground -
penetrating radar (GPR). Putting it very basically, GPR works by sending
microwave radio pulses down into the soil, then analyzing the manner in which
underground elements reflect those signals back to the surface. No digging is
required.
The scientists performed GPR
scans at seven sites in Russia's Kamennaya Steppe nature preserve, which is
known for its multiple soil types. They also took 30 core samples from each
site, down to depths ranging from 10 cm (3.9 in) to 3 meters (9.8 ft). The GPR
scans' red, green and blue wavelength data was then compared to the various
colors at different levels in the corresponding core samples. Doing so
established a model that matched different wavelength readings to different soil
colors.
It was subsequently found that by
applying that model to GPR data alone, it was possible to determine the
underground soil colors at a given site with 80 percent accuracy. That figure
should improve as the technology is developed further. However, it should also
be noted that in its current form, the system initially has to be calibrated
using a core sample from the target region – scans can then be performed at
multiple sites within that region, without the need for additional samples.
A paper on the research was
recently published in the journal Eurasian
Soil Science.
Source:
https://newatlas.com/science/ground-penetrating-radar-soil-sampling/ RUDN
University via EurekAlert