Comparable discrimination of soil constituents using spectral reflectance data (400-1000 nm) acquired with hyperspectral radiometry

Authors: Starks, Patrick; Fortuna, Ann Marie

Submitted to: Soil Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/5/2021
Publication Date: 8/11/2021
Citation: Starks, P.J., Fortuna, A. 2021. Comparable discrimination of soil constituents using spectral reflectance data (400-1000 nm) acquired with hyperspectral radiometry. Soil Systems. 5. Article 45.

Interpretive Summary: Currently, a gap exists in inventorying, monitoring, parameterizing, and validating the impact of land use and management on soil resources. Previously, we successfully deployed a research grade, field spectrometer to correlate soil carbon fractions and nitrogen to hyperspectral diffuse reflectance (HDR), over the 350-2500 nm wavelength range of the electromagnetic spectrum. This research is an extension of preceding research but focuses solely on the 400-1000 nm (visible through near-infrared (VIS-NIR)) region of the electromagnetic spectrum. This region can be measured using less expensive, miniaturized, field spectrometers that allow minimal sample preparation. Our objectives were to: 1) evaluate further the use of soil HDR in the VIS-NIR acquired using a research grade field hyperspectral spectroradiometer for prediction of soil carbon (C) and nitrogen (N) constituents, 2) repeat objective 1) but using less expensive hyperspectral radiometers, and 3) add to the limited literature that addresses determinations of selected soil properties using remote/proximal sensing in the VIS-NIR region. Data analyzed in this study confirms that good to satisfactory prediction equations for soil constituents can be developed from spectral reflectance data within the 400-1000 nm wavelength region obtained using relatively inexpensive field radiometers. Adoption of this research will lead to more timely and less costly soil sample analysis.

Technical Abstract: Currently, a gap exists in inventorying, monitoring, parameterizing, and validating the impact of land use and management on soil resources. Previously, we successfully deployed a research grade, field spectrometer as a benchtop system to correlate soil carbon fractions and nitrogen to hyperspectral diffuse reflectance (HDR), over the 350-2500 nm wavelength range. This research is an extension of preceding research but focuses solely on the 400-1000 nm (visible through near-infrared (VIS-NIR)) region of the electromagnetic spectrum. This region can be measured using less expensive, miniaturized, field spectrometers that allow minimal sample preparation. Our objectives were to: 1) evaluate further the use of soil HDR in the VIS-NIR acquired using a research grade field hyperspectral spectroradiometer for prediction of soil carbon (C) and nitrogen (N) constituents, 2) repeat objective 1) but using less expensive hyperspectral radiometers, and 3) add to the limited literature that addresses determinations of selected soil properties using proximal sensing in the VIS-NIR region. Data analyzed in this study confirms that good to satisfactory prediction equations for soil constituents can be developed from spectral reflectance data within the 400-1000 nm wavelength region obtained using relatively inexpensive field radiometers.