Submitted to: Soil Science Society of America Journal
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/15/2002
Publication Date: 6/1/2002
Citation: MCCARTY,G.W., REEVES III,J.B., FOLLETT,R.F., KIMBLE,J.M., MID-INFRARED AND NEAR-INFRARED DIFFUSE REFLECTANCE SPECTROSCOPY FOR SOIL CARBON MEASUREMENT, SOIL SCIENCE SOCIETY OF AMERICA JOURNAL, 66:640-646. Interpretive Summary: Most of the work on spectral Analysis for quantifying soil properties has been focused on use of NIRS, but our comparison of NIRS and MIRS provides strong evidence that MIR spectral contain better information related to soil C. These results indicate that greater effort should be given to developing MIRS instrumentation for environmental sampling and approaches to extract information contained in MIR spectra on soil composition
Technical Abstract: 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 US. The soils temperature regimes ranged from thermic to frigid and the soil moisture regimes from udic to aridic. The soil ranged considerably in organic (0.23 - 98 g C/kg) and inorganic C content (0.0 to 65.4 g carbonate C/kg). These soil samples were analyzed with and without an acid treatment for removal of carbonate. Both spectral regions contained subastantial information on organic and inorganic C in soils studied and MIR analysis substantially outperformed NIR. The ability of MIR spectroscopy to quantify C in diverse soils collected over a large geographic region indicated that regional calibrations are feasible.