HR: 1340h
AN: U43C-1404    [Abstracts]
TI: Simulated in situ Determination of Soil Profile Organic and Inorganic Carbon Using Combined VisNIR and LIBS Sensors
AU: * Bricklemyer, R S
EM: rsb@wsu.edu
AF: Dept. of Crop and Soil Sciences, Washington State University, 201 Johnson Hall, Pullman, WA 99164, United States
AU: Brown, D J
EM: david_brown@wsu.edu
AF: Dept. of Crop and Soil Sciences, Washington State University, 201 Johnson Hall, Pullman, WA 99164, United States
AU: Clegg, S M
EM: sclegg@lanl.gov
AF: Advanced Diagnostics and Instrumentation Group, Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM 87545, United States
AU: Barefield, J E
EM: jbarefield@lanl.gov
AF: Advanced Diagnostics and Instrumentation Group, Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM 87545, United States
AB: There is growing need for rapid, accurate, and inexpensive methods to measure, and verify soil organic carbon (SOC) change for national greenhouse gas accounting and the development of a soil carbon trading market. Visible and Near Infrared Spectroscopy (VisNIR) and Laser Induced Breakdown Spectroscopy (LIBS) techniques have the potential to fill that need. LIBS and VisNIR are fundamentally different and complementary technologies. LIBS provides precise elemental analysis of soils, but cannot distinguish between organic C and inorganic C. VisNIR has been used to characterize soil mineral and molecular composition and can distinguish between organic C and inorganic C. In this study we evaluated the precision of a simulated in situ VisNIR/LIBS proximal sensing array for soil profile carbon measurement. We simulated the in situ system by scanning 120 intact soil cores (3.8 cm x 50 cm) from three agricultural fields in north central Montana, USA. VisNIR measurements were taken using an Analytical Spectral Devices (ASD, Boulder, CO, USA) Agrispec spectrometer. LIBS measurements involved focusing a Nd:YAG laser onto the surface of the soil core to produce a plasma. The spectra from emitted plasma light were detected with a charge- coupled device. LIBS and VisNIR measurements were taken concurrently at 5 cm increments along each intact soil core. Subsamples of soil ({~} 4 g) were taken from interrogation points, and then each core was cut into 10 cm increments for carbon analysis. A representative subset (192 samples) of the interrogation point samples were used to calibrate and validate several VisNIR/LIBS models to compare VisNIR /LIBS vs. standard organic and inorganic carbon analysis.
DE: 1094 Instruments and techniques
DE: 1631 Land/atmosphere interactions (1218, 1843, 3322)
DE: 1694 Instruments and techniques
SC: Union [U]
MN: 2007 Fall Meeting