From the DARWin SP screen, the 19 vegetation indices including NDVI are
accessed via a pull down menu.
Measuring Soil Salinity
1 Canal Street ◊ Unit B1
Lawrence, MA 01840 USA
Tel: 978 687-1833 ◊ Fax: 978 945-0372
Copyright © 2012 Spectral Evolution, Inc
Measuring soil salinity is important for efficient soil and water
management in arid and semi-arid environments. Excess salinity can
be caused by nature or man: lack of rainfall, erosion, and rising water
tables can cause salts to accumulate in the upper soil layers; so too
can improper irrigation practices. Degradation of soil has a negative
impact on agriculture as well as the environment.
Soil salinity has a direct effect on the variety and quality of
vegetation that can grow in an area. Excess salinity can diminish
water uptake in plants while the presence of high salinity in clay can
destroy good soil structure.
The PSR+ field spectroradiometer offers an accurate,
non-destructive instrument for measuring salinity in soils in situ that
is faster and less expensive than traditional lab-based electrical
conductivity tests. Used alone or in conjunction with multi-spectral
and hyperspectral imaging from flyovers and satellites, the PSR+ can
offer a more complete picture of soil salinity across a large area.
Scans taken in the VNIR bands (visible, near infrared) from
350-1000nm contain data on soil color, presence of iron, moisture,
and organic matter. Scans in the near infrared (NIR) bands from
1000-2500nm can provide data on silicates, hydroxides, some
sulphates, amphiboles, carbonates, water, and organic matter. The
PSR+ covers the full range from 350-2500nm with three photodiode
Spectra collected in the field or the lab with a PSR+ portable
agricultural spectroradiometer are saved as ASCII files for analysis
using third party software, for example the R software analysis
program or a chemometrics package.
In plants suffering from salinity stress, there is increased visible
reflectance and decreased NIR reflectance. For researchers who
want to use vegetation indices such as the Normalized Difference
Vegetation Index (NDVI) or Soil Adjusted Vegetation Index (SAVI),
there is access to these and 17 other vegetation indices from the
PSR+ DARWin SP Data Acquisition software included with every
In addition, for those working with an existing soil spectral library or
who want to build their own library, the optional EZ-ID sample
identification software with Custom Library Builder module is
available. EZ-ID provides fast sample identification by matching a
scan from an unknown target sample to a known sample spectra from
a library. Making your own library is as easy as scanning and adding
metadata to your file.
The PSR+ 3500 is a field portable spectroradiometer for
remote sensing applications including soil salinity studies.
With DARWin SP Data Acquisition Software included, it
provides instant access to 19 vegetation indices for your