Knowledge of subsurface soil elemental content distribution over agricultural fields is important for optimizing modern agricultural practices and enhancing soil science knowledge. For example, soil carbon is a strong determinant of soil quality, crop productivity, and farm profitability. Thus, accurate field mapping of soil carbon can be beneficial in assessing modern agricultural practices and management decisions for enhancing carbon sequestration and has potential relevance to emerging carbon credit markets. Such soil carbon determinations are desirable since traditional chemical analysis of primary soil elements (particularly carbon) is laborious and time consuming due to the large sample numbers required (to account for landscape variability) and extensive laboratory processing. The neutron-stimulated gamma analysis method can be used for in-situ measurements of primary elements in agricultural soils (e.g., Si, Al, O, C, Fe, and H). This is a non-destructive method that requires no sample preparation a d can perform multi-elemental analyses of large soil volumes. Measurement results are negligibly impacted by local sharp changes in elemental contents. Neutron-gamma soil elemental analysis is based on registration of gamma rays issued from nuclei upon interaction with neutrons; gamma rays are issued due to different processes of neutron-nuclei interactions. For primary soil elements, characteristic gamma lines can be used for content determinations in soil. To attain suitable accuracy, elemental content measurements should continue for ~15 minutes per site. Paired with GPS, our developed scanning methodology acquires data that can be directly used for creating soil elemental distribution maps (based on ArcGIS software) in a reasonable timeframe (~20-30 hectares per working day). Created maps are suitable for both agricultural purposes and carbon sequestration estimates. In this presentation, recent USDA-ARS NSDL developments concerning neutron gamma analysis applications will be discussed in more detail.
Graduate of the Institute of Technology (Leningrad, USSR) and majored in Radiation Chemistry and Nuclear Physics. Approximately 30 years of experience in Applied Radiation Chemistry and Applied Nuclear Physics. Beginning in 2013, worked at the National Soil Dynamics Laboratory (USDA-ARS, Auburn, AL, USA) on applying nuclear methods (primarily neutron-gamma analysis) for soil elemental analysis
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