ASSOCIATION BETWEEN BOTANICAL COMPOSITION AND BIOMASS QUANTITY OF GRASSLANDS AND NIR REFLECTANCE BY USING NDVI

Bozkurt Yalçin

Abstract
    It was aimed to investigate the possible association between botanical composition and biomass quantity and NIR (Near Infra Red) reflectance by using NDVI (Normalised Difference Vegetation Index) derived from remote sensing data. For this purpose, red (0.45-0.52 µm), near infra-red (0.52-0.60 µm) and infra-red (0.63-0.69 µm) spectral bands of the LANDSAT 5 TM satellite images taken in 2005 were used and NDVI was calculated as a ratio between measured reflectivity in the red and NIR portions of the electromagnetic spectrum. The field measurements were also carried out in north eastern part of Turkey in 23 test points during vegetation period to determine botanical composition and fresh biomass quantity. Regression analysis showed that there was a poor relationship between botanical composition and NDVI (R²=0.22) while a good coefficient of determination was observed between fresh biomass quantity and NDVI (R²=0.67). It can be concluded that field spectral measurements and satellite derived information can provide a valuable support and information to the evaluation of grasslands.

Key words: Grasslands, remote sensing, NIR, NDVI