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Mid‐Infrared and Near‐Infrared Diffuse Reflectance Spectroscopy for Soil Carbon Measurement
Author(s) -
McCarty G. W.,
Reeves J. B.,
Reeves V. B.,
Follett R. F.,
Kimble J. M.
Publication year - 2002
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2002.6400a
Subject(s) - soil water , soil carbon , total organic carbon , udic moisture regime , diffuse reflectance infrared fourier transform , soil test , environmental science , soil science , spectroscopy , infrared spectroscopy , environmental chemistry , chemistry , biochemistry , physics , organic chemistry , loam , photocatalysis , quantum mechanics , catalysis
The ability to inventory soil C on landscapes is limited by the ability to rapidly measure soil C. Diffuse reflectance spectroscopic analysis in the near‐infrared (NIR, 400–2500 nm) and mid‐infrared (MIR, 2500–25000 nm) regions provides means for measurement of soil C. To assess the utility of spectroscopy for soil C analysis, we compared the ability to obtain information from these spectral regions to quantify total, organic, and inorganic C in samples representing 14 soil series collected over a large region in the west central United States. The soils temperature regimes ranged from thermic to frigid and the soil moisture regimes from udic to aridic. The soils ranged considerably in organic (0.23–98 g C kg −1 ) and inorganic C content (0.0–65.4 g CO 3 ‐C kg −1 ). These soil samples were analyzed with and without an acid treatment for removal of CO 3 Both spectral regions contained substantial information on organic and inorganic C in soils studied and MIR analysis substantially outperformed NIR. The superior performance of the MIR region likely reflects higher quality of information for soil C in this region. The spectral signature of inorganic C was very strong relative to soil organic C. The presence of CO 3 reduced ability to quantify organic C using MIR as indicated by improved ability to measure organic C in acidified soil samples. The ability of MIR spectroscopy to quantify C in diverse soils collected over a large geographic region indicated that regional calibrations are feasible.