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ARS Home » Southeast Area » Auburn, Alabama » Soil Dynamics Research » Research » Publications at this Location » Publication #360771

Research Project: Enhancing Production and Ecosystem Services of Horticultural and Agricultural Systems in the Southeastern United States

Location: Soil Dynamics Research

Title: Tagged neutron method for carbon analysis of large soil samples

item Yakubova, Galina
item KAVETSKIY, ALEKSANDR - Auburn University
item Prior, Stephen - Steve
item Torbert, Henry - Allen

Submitted to: Applied Radiation And Isotopes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/19/2019
Publication Date: 5/24/2019
Citation: Yakubova, G.N., Kavetskiy, A., Prior, S.A., Torbert III, H.A. 2019. Tagged neutron method for carbon analysis of large soil samples. Applied Radiation And Isotopes. 150:127-134.

Interpretive Summary: The uptake of carbon from atmospheric in the form of CO2 by plants can help mitigate global change through soil carbon storage. This project covers the development of an alternative to the traditional dry combustion method of measuring soil carbon in samples collected in the field. This paper discusses the experimental setup and developed procedures for using the tagged neutron method to measure carbon. This method can handle larger samples and measure carbon in a timelier manner than the traditional dry combustion method.

Technical Abstract: Laboratory determination of carbon content in 30-50 kg soil samples is described. The method is based on measuring sample gamma spectra using the tagged neutron technique. Determining sample weight and moisture content are required for this method. The presented physical model establishes a correlation between carbon peak area of the measured gamma spectra and sample carbon content while accounting for neutron and gamma flux attenuation. Monte-Carlo computer simulations (Geant4) were applied to understand detailed steps for carbon analysis, and simulation results are discussed. Based on the physical model and simulation results, experimental procedures for determining carbon content of large soil volumes (several dozen cubic decimeters) were developed. Measurement results demonstrate good agreement with standard chemical analysis, independent of sample soil density and moisture. Due to this agreement, the tagged neutron technique can be recommended as an alternate method for laboratory determination of soil carbon in 40-50 kg samples.