Soil chemical compostion and texture determinations using neutron-gamma analysis

Authors: Yakubova, Galina; Kavetskiy, Aleksandr; GAUTAM, SIDHARTH - Auburn University; Prior, Stephen; Torbert Iii, Henry

Submitted to: Soil and Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/10/2025
Publication Date: 10/16/2025
Citation: Yakubova, G.N., Kavetskiy, A.G., Gautam, S., Prior, S.A., Torbert III, H.A. 2025. Soil chemical compostion and texture determinations using neutron-gamma analysis. Soil and Tillage Research. 256:1016912. https://doi.org/10.1016/j.still.2025.106912.
DOI: https://doi.org/10.1016/j.still.2025.106912

Interpretive Summary: Knowledge of soil texture across fields is important for both modern agricultural practices and basic soil science research. We developed a mobile system using the Tagged Neutron Method (TNM) to measure primary soil components and can be used to determine soil texture. This in-situ method is non-destructive, relatively fast, radiation-safe, and requires no sample preparation or laboratory processing. Since soil characteristics (including soil texture) measured by TNM were in good agreement with traditional methods, TNM could be considered a good alternative for routine soil science measurements and selecting appropriate agricultural practices.

Technical Abstract: Knowledge of primary subsurface soil components SiO2, Al2O3, Fe2O3, C, H2O, CaO, etc.) and soil texture across fields is important for both modern agricultural practices and soil science research. Soil coring and subsequent laboratory sample processing are labor-intensive and time-consuming. Neutron-stimulated gamma analysis is a good alternative to traditional methods of determining soil elements. The Tagged Neutron Method (TNM) is a modification of this analysis that can determine primary soil components. This in-situ method is non-destructive, relatively fast, radiation-safe, and requires no sample preparation or laboratory processing. This method involves measuring inelastic neutron scattering gamma spectra in tagged neutron mode and subsequent deconvolution of these spectra into reference component spectra. A mobile field system was developed and constructed to carry out these measurements. Algorithms and computer code were developed for spectra deconvolution and determination of soil component levels. The ratio of soil Al2O3 to SiO2 was found to be related to soil texture. Field experiments showed that values of these two soil components can be used for in-situ soil texture determination. Since soil characteristics (including soil texture) measured by TNM were in good agreement with traditional methods, TNM could be considered a good alternative for routine soil science measurements and selecting appropriate agricultural practices.