Estimating Leaf Area Index for an arid region using Spectral Data.

Leaf Area Index (LAI) is one of the important crop parameters that can be used to assess crop conditions or drought severity. Estimating LAI for arid regions presents challenge due to the high spatial variability in precipitation and in crop canopies found in such regions. In this study, spectral reflectance of pearl millet was computed at various wavelengths and at different times during the cropping season, using a spectroradiometer. Three main indices (Normalised Difference Vegetation Index, Ratio Vegetation Index, and Perpendicular Vegetation Index)were derived from the spectral data. These indices were then correlated with the leaf area index in order to identify the index that gave the strongest relationship. A polynomial relationship, with the coefficient of correlation of 0.70, was found between LAI and NDVI indicating that NDVI is a potential index for estimating LAI for aridregions. Key Words: Arid lands, Leaf area index, vegetation indices