Predicting leaf and canopy 15 N compositions from reflectance spectra

We explored whether 15 N concentration could be predicted from reflectance spectra of fresh leaves, and, if so, whether the spectral features were related to the 15 N concentration on a canopy scale. Leaf scale reflectance (R) measurements were conducted in Ghanzi, Botswana using a spectrophotometer in March 2005 and canopy scale leaf R was measured in a series of successional fields in Northern Virginia, USA using the same instrument in September 2005. Results showed that there was a strong correlation between foliar 15 N concentration and spectral data in both visible and near‐infrared wavelength regions. Stepwise regressions showed that the first‐difference of the log1/R [(log 1/R)′] could explain 76 to 92% of the variation in foliar δ 15 N, providing the most reliable correlations with foliar 15 N at bands near 600 and 700 nm. The present study indicates the possibility of estimating fresh leaf 15 N abundance from high‐resolution reflectance at leaf and canopy levels.