1 / 11

NDVI: What It Is and What It Measures

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? .

tait
Download Presentation

NDVI: What It Is and What It Measures

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. NDVI: What It Is and What It Measures DanielleWilliams

  2. 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

  3. What does NDVI measure? • “greenness” i.e. chlorophyll content • correlated with biomass • represent N status of plant

  4. How does it work? • Light • -absorbed • -transmitted • -reflected • Different pigments stimulated by • different parts of light spectrum

  5. 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

  6. Uses of NDVI • water stress • N stress/uptake • P stress/ uptake • Anything if it is the limiting/excess factor • disease?

  7. 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

  8. Why use NDVI? • indirect measurement • less time • more cost effective • more precise application of fertilizer • unbiased

  9. NDVI over duration of season(Mahey et al. 1991)

  10. Future research • other nutrients other than N • calibrations for crops • disease

  11. Questions???

More Related