Predicting 15N Concentrations From Reflectance Spectra (400-2500 nm) at Leaf and Canopy Scales
Abstract
Chemical analyses based on reflectance spectrometry can be as accurate as traditional wet-chemistry procedures for determining leaf nitrogen content. In many ecosystems there is also a known relationship between leaf nitrogen content and 15N composition. In this study, we explored whether natural abundance 15N concentrations could be predicted from reflectance spectra of fresh leaves, and, if so, whether the spectral features could be related to the 15N concentrations on a canopy scale. The leaf scale reflectance measurements were conducted in Ghanzi, Botswana, using a spectrophotometer in March 2005. Canopy scale leaf reflectance was measured in September 2005 on a series of successional fields at the Blandy Experimental Farm in northern Virginia, USA using the same instrument. Our results showed that there is a strong correlation between foliar 15N concentration and the spectral data, and the best predictors for 15N concentration at both leaf and canopy scales are R (reflectance) and log 1/R at both visible band and near-infrared band. The present study pointed out the possibility of estimating the 15N compositions of fresh leaves from non-agricultural areas using high-resolution reflectance spectra data.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFM.B41D0217W
- Keywords:
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- 0400 BIOGEOSCIENCES;
- 1615 Biogeochemical cycles;
- processes;
- and modeling (0412;
- 0414;
- 0793;
- 4805;
- 1851 Plant ecology (0476)