Nutrient estimation of eucalypt foliage derived from hyperspectral data

In this study we evaluate the potential of hyperspectral data for remote measurement of foliar nutrient status of nitrogen (N), phosphorus (P) and potassium (K) in five Eucalyptus species of dry sclerophyll forest. Reflectance spectra (400-2500 nm) were obtained for dried, ground leaves using near infrared spectroscopy (NIRS), and for dried and fresh whole leaves using a laboratory-based FieldSpec spectroradiometer. Coefficients of variation (CV) for prediction of N ranged from 5%-8%, for P 18-26% and for K 14-23%. N and K were most accurately predicted using NIRS, and P from the fresh leaf measurements. The predictive equations developed for P are based largely on absorbance features associated with N, whilst those for K appear to be associated with absorption due to the presence of carbohydrates (sucrose, starch and cellulose), and for the fresh leaf, water content