Paper Info
Title
Savanna grass nitrogen to phosphorous ratio estimation using field spectroscopy and the potential for estimation with imaging spectroscopy.
Abstract
Determining the foliar N:P ratio provides a tool for understanding nutrient limitation on plant production and consequently for the feeding patterns of herbivores. In order to understand the nutrient limitation at landscape scale, remote sensing techniques offer that opportunity. The objective of this study is to investigate the utility of field spectroscopy and a potential of hyperspectral mapper (HyMap) spectra to estimate foliar N:P ratio. Field spectral measurements were undertaken, and grass samples were collected for foliar N and P extraction. The foliar N:P ratio prediction models were developed using partial least square regression (PLSR) with original spectra and transformed spectra for field and the resampled field spectra to HyMap. Spectral transformations included the continuum removal (CR), water removal (WR), first difference derivative (FD) and log transformation (Log(1/R)). The results showed that CR and WR spectra in combination with PLSR predicted foliar N:P ratio with higher accuracy as compared to FD and R, using field spectra. For HyMap spectral analysis, addition to CR and WR, FD achieved higher estimation accuracy. The performance of FD, CR and WR spectra were attributed to their ability to minimize sensor and water effects on the fresh leaf spectra, respectively. The study demonstrated a potential to predict foliar N:P ratio using field and HyMap simulated spectra and shortwave infrared (SWIR) found to be highly sensitive to foliar N:P ratio. The study recommends the prediction of foliar N:P ratio at landscape level using airborne hyperspectral data and could be used by the resource managers, park managers, farmers and ecologists to understand the feeding patterns, resource selection and distribution of herbivores (i.e. wild and livestock). (C) 2012 Elsevier B.V. All rights reserved.
Year
DOI
Venue
2013
10.1016/j.jag.2012.10.009
International Journal of Applied Earth Observation and Geoinformation
Keywords
Field
DocType
Nitrogen,Phosphorus,N:P,Water removed spectra,Grass,Estimation,Savanna ecosystem,Spectroscopy
Nitrogen,Remote sensing,Partial least squares regression,Shortwave,Hyperspectral imaging,Spectroscopy,HyMap,Geography,Nutrient,Imaging spectroscopy
Journal
Volume
ISSN
Citations 
23
0303-2434
2
PageRank 
References 
Authors
0.67
3
6
Name
Order
Citations
PageRank
a ramoelo1509.30
Andrew K. Skidmore241470.54
Martin Schlerf39412.32
Ignas M. A. Heitkönig4285.14
Renaud Mathieu512517.29
Moses Azong Cho617820.10