Use of near-infrared reflectance spectroscopy in predicting nitrogen, phosphorus and calcium contents in heterogeneous woody plant species
Near-infrared reflectance spectroscopy was applied to determine nitrogen (N), phosphorus (P) and calcium (Ca) content in leaf samples of 18 woody species. A total of 183 samples from mountain, riparian and dry areas from the Central-Western Iberian Peninsula were collected for this purpose. The wide intervals of variation observed in nutrient concentrations (6.6-45.0 g kg -1 for N, 0.24-2.97 g kg-1 for P, and 1.00-20.06 g kg -1 for Ca) were due to the great heterogeneity of the samples. To develop calibration equations, multiple linear regression, and partial least-squares regression (PLSR) were used. In both cases, three mathematical transformations of the data were applied: log1/R and first and second derivatives. The best calibration statistics were obtained using PLSR and derivative transformations (second derivative for N and first derivative for P and Ca). The following coefficients of multiple determination (R 2) and standard errors of cross validation were obtained: 0.99 and 0.93 for N, 0.94 and 0.15 for P, and 0.95 and 0.88 for Ca. In the external validation the standard errors of prediction obtained were 0.76 (N), 0.11 (P) and 0.60 (Ca)
| Main Authors: | , , , , , |
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| Other Authors: | |
| Format: | artículo biblioteca |
| Published: |
Springer
2005-05
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| Subjects: | Chemical composition, Near-infrared reflectance spectroscopy (NIRS), Woody plant species, |
| Online Access: | http://hdl.handle.net/10261/258805 http://dx.doi.org/10.13039/501100014180 http://dx.doi.org/10.13039/501100006280 http://dx.doi.org/10.13039/501100003176 |
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