Every Spectral Evolution instrument includes DARWin SP
Data Acquisition software with 19 built-in vegetation indices,
including PRI and the Red/Green index.
Estimating Nitrogen Content in Vegetation
 First in Full Range PDA Spectrometer, Spectroradiometer and Spectrophotometer Systems
1 Canal Street  ◊  Unit B1
Lawrence, MA 01840  USA
Tel: 978 687-1833  ◊  Fax: 978 945-0372

Copyright © 2012 Spectral Evolution, Inc
The leaf clip includes a built-in white reference and is designed to keep the heat from the illumination away
from your sample so that measurements can be accurate and non-destructive.
Using a field spectroradiometer such as the Spectral Evolution PSR+
or the
RS-3500, a researcher can get an estimate of nitrogen content
in a plant or a canopy for a fast overview of plant health. Like
phosphorous, potassium, calcium, and magnesium, nitrogen is a
nutrient  crucial to photosynthesis and affects the production of
plant chlorophyll. All nutrient deficiencies in some way affect
chlorophyll content with a generally increased reflectance in the
visible wavelengths (400-700nm) and the infrared (700-1100nm). In
general, nutrient deficiency of any kind will represent a chlorophyll
loss and a shift in the position of the “red edge” to  a shorter

The red edge is usually situated around 720nm. For nitrogen
deficient plants, the red edge may be closer to 700nm and the actual
slope of the red edge should be slightly steeper (signifying higher
reflectance of the sample) than normal for a healthy plant. It is also
possible to estimate total plant nitrogen using spectral reflectance
measurements at the red at 671nm and the NIR at the 780nm

The PSR+ and RS-3500 are both portable full range, UV-VIS-NIR
instruments designed for field use.
 First in Full Range PDA Spectrometer, Spectroradiometer and Spectrophotometer Systems
PSR+ with the unique leaf clip for vegetation research in the field.
Closeup on the position and
steepness of the red edge in a
plant leaf scan for estimating
nitrogen deficiency. In this
multi-scan plot, the purple
scan indicates a slightly less
healthy sample.