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NDVI: What It Is and What It Measures. Danielle Williams. What is NDVI?. Normalized difference vegetation index mathematical formula derived to form a single spectral based number more sensitive than just a single wavelength ratio - no units. What does NDVI measure? .

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Ndvi what it is and what it measures l.jpg

NDVI: What It Is and What It Measures

DanielleWilliams


What is ndvi l.jpg
What is NDVI?

  • Normalized difference vegetation index

  • mathematical formula derived to form a single spectral based number

    • more sensitive than just a single wavelength

  • ratio - no units


What does ndvi measure l.jpg
What does NDVI measure?

  • “greenness” i.e. chlorophyll content

    • correlated with biomass

    • represent N status of plant


Slide4 l.jpg

How does it work?

  • Light

  • -absorbed

  • -transmitted

  • -reflected

  • Different pigments stimulated by

  • different parts of light spectrum


Ndvi ir red ir red l.jpg
NDVI= IR-Red / IR+ Red

IR 750-1300 nm

Red 600-700nm

Chlorophyll greenness of leaf

- activity @ 645 and 663nm

Reflected green color peaks

at 550nm


Uses of ndvi l.jpg
Uses of NDVI

  • water stress

  • N stress/uptake

  • P stress/ uptake

  • Anything if it is the limiting/excess factor

  • disease?


Factors affecting ndvi l.jpg
Factors affecting NDVI

  • leaf morphology

  • growth stage (Sembiring et al, 2000)

  • variety (Sembiring et al. ,2000)

  • crop

  • row spacing/planting density

    (Lukina et al, 2000)

  • soil type (Heilman and Kress, 1987)

  • canopy cover

  • environmental stress


Why use ndvi l.jpg
Why use NDVI?

  • indirect measurement

    • less time

    • more cost effective

    • more precise application of fertilizer

    • unbiased


Ndvi over duration of season mahey et al 1991 l.jpg
NDVI over duration of season(Mahey et al. 1991)


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Future research

  • other nutrients other than N

  • calibrations for crops

  • disease