Novel Multivariate Analysis for Soil Carbon Measurements Using Laser-Induced Breakdown Spectroscopy

Journal Article · Fri Jan 01 04:00:00 EST 2010 · Soil Science Society of America Journal

DOI:https://doi.org/10.2136/sssaj2009.0102· OSTI ID:979182

Martin, Madhavi Z ^[1]; Labbe, Nicole ^[1]; Andre, Nicolas O ^[1]; Wullschleger, Stan D ^[1]; Harris, Ronny D ^[1]; Ebinger, Michael H ^[1]

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1. ORNL

Laser-induced breakdown spectroscopy (LIBS), a rapid and potentially field-deployable technology for estimating total carbon in soil, represents a novel approach to address important issues in soil science and carbon management. Our study has shown that models relating LIBS signal intensity at 247.85 nm to percent total carbon determined by dry combustion vary as a function of elemental and textural characteristics of the soil, and, to a lesser extent, wavelength and excitation energy of the laser. To better quantify these sources of variation, two wavelengths and three excitation energies were used to analyze soils from various locations. The emission line of carbon at 247.85 nm was pronounced at an excitation wavelength of 532 nm and energy of 45 mJ, but it was largely obscured by the 248.9 nm Fe line at 1064 nm and excitation energies of 90 and 135 mJ. Univariate analysis revealed linear, but soil-specific correlations between signal intensity at 247.85 nm and total carbon concentration. A single calibration model correlating LIBS spectra to carbon concentration in all samples was obtained using a multivariate approach. Several emission lines in addition to the strong carbon line contributed significantly to the multivariate model. These results show that multivariate analysis can be used to construct a robust calibration model for LIBS spectra and therein provide a reliable estimate of total soil carbon. Such results must be confirmed for a broader range of soils, yet crop and soil scientists, carbon managers, and instrument developers should find these results encouraging.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 979182
• Journal Information: Soil Science Society of America Journal, Journal Name: Soil Science Society of America Journal Journal Issue: 1 Vol. 74; ISSN 0361-5995; ISSN SSSJD4
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
BREAKDOWN
CALIBRATION
CARBON
COMBUSTION
CROPS
EXCITATION
INS
LIBS
MANAGEMENT
MULTIVARIATE ANALYSIS
MVA
Nd:YAG
PCA
PLS
RMSEC
SOILS
SPECTRA
SPECTROSCOPY
WAVELENGTHS
inelastic neutron scattering
laser-induced breakdown spectroscopy
multivariate analysis
neodymium yttrium aluminum garnet
principal component analysis
projection to latent structures
root mean square error of