HR: 16:00h
AN: H34D-01 INVITED     [Abstracts]
TI: On-the-go Near Infrared Reflectance Spectroscopy Analysis of Soils
AU: * Laird, D A
EM: laird@nstl.gov
AF: USDA, ARS, NSTL, 2150 Pammel Drive, Ames, IA 50011 United States
AU: Christy, C
EM: christyc@geoprobesystems.com
AF: Veris Technologies, 601 N. Broadway Blvd, Salina, KS 67401 United States
AB: Soil sensors are needed for carbon sequestration assessment, precision farming, and soil quality assessment. We tested the capabilities of a prototype for a field mobile, on-the-go, Near Infrared Reflectance (NIR) spectrometer system built by Veris Technologies, Inc. (Salina KS). The system consisted of an optical system embedded in a steel shank, which can be pulled through the soil behind a tractor at a controlled depth. The optical system consists of a sapphire window in the base of the steel shank fiber, a light source, and a fiber optic cable that transports diffusely reflected light from the soil in contact with the window to the NIR spectrometer. The system also includes a GPS unit and a computer that accumulates both the spectral and GPS data. The system was tested in two agricultural fields by collecting real time spectra (20 spectra per second, 350 to 1700 nm) along 30 or 37 transects within the fields. Approximately 150 soil samples were collected from each field at known locations from the smear face left by the steel shank at the base of the furrow. The soil samples were analyzed for moisture content, organic C, total N, pH, SMP-buffer pH, and ECEC by sum of ammonium acetate extractable Ca, Mg, K, Na, and Al. Multivariate partial least squares calibration models were developed using The Unscrambler (Camo Process, Inc.) to relate the measured soil properties to the field collected spectra. The results demonstrate the ability of the system to distinguish unique management zones (low, medium, and high) for N-fertilization, K-fertilization, and lime requirement. The system also provides a means of mapping the spatial distribution of organic C, total N, ECEC, moisture and several other soil properties in agricultural fields.
DE: 1866 Soil moisture
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting