Which statement is true about NDVI limitations?

Which statement is true about NDVI limitations?

• A. NDVI saturates in dense canopies.
• B. NDVI is not affected by soil background effects.
• C. NDVI cannot be influenced by soil background effects.
• D. NDVI never has any limitations.

Answer: (B)

NDVI limitations arise from how the signal reacts to both very dense and very sparse vegetation. In dense canopies, the reflectance in the red band drops while near-infrared stays high, but after a point the response levels off. This saturation means NDVI stops changing much even if biomass increases, so it becomes less sensitive to additional greenness. In sparse vegetation, soil brightness and color mix with the vegetative signal, so the soil background can bias NDVI values and make it harder to tell whether changes are due to plants or the soil. Because of these effects, NDVI is not immune to limitations and can be influenced by soil background. The statement that NDVI is not affected by soil background or that it has no limitations isn’t accurate; the true limitation to remember is that NDVI can saturate in dense canopies while also being affected by soil background in sparse areas.

NDVI limitations arise from how the signal reacts to both very dense and very sparse vegetation. In dense canopies, the reflectance in the red band drops while near-infrared stays high, but after a point the response levels off. This saturation means NDVI stops changing much even if biomass increases, so it becomes less sensitive to additional greenness. In sparse vegetation, soil brightness and color mix with the vegetative signal, so the soil background can bias NDVI values and make it harder to tell whether changes are due to plants or the soil. Because of these effects, NDVI is not immune to limitations and can be influenced by soil background. The statement that NDVI is not affected by soil background or that it has no limitations isn’t accurate; the true limitation to remember is that NDVI can saturate in dense canopies while also being affected by soil background in sparse areas.