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Field testing a mobile inelastic neutron scattering system to measure soil carbon
- Galina Yakubova, Lucian Wielopolski, H. Allen Torbert, Stephen A. Prior
- Soil science 2014 v.179 no.12 pp. 529-535
- neutron probes, soil organic carbon, models, soil, soil analysis, laboratory experimentation, combustion, soil management, field experimentation, cropping sequence
- Cropping history in conjunction with soil management prac- tices can have a major impact on the amount of organic carbon stored in soil. Current methods of assessing soil carbon based on soil coring and sub- sequent processing procedures before laboratory analysis are labor inten- sive and time-consuming. Development of alternative methods that can make in situ field measurements of soil carbon is needed to successfully evaluate management practices in a timely manner. The robust design, field testing procedure, and results of measuring soil carbon in situ using a mo- bile inelastic neutron scattering (MINS) system are described. A method of MINS spectra data processing that gives more accurate peak area determi- nation compared with the traditional “trapezoidal” method is described. The MINS reliable autonomous operation for 29 h per charge cycle was demonstrated in the field. For comparison, soil cores were also collected for laboratory carbon analysis using the dry combustion technique. Soil carbon assessments by dry combustion technique and MINS demonstrated a linear correlation between the two methods in the 0- to 30-cm soil layer. Based on the developed theoretical model of MINS measurement, we dem- onstrated that accurate soil carbon determination by this method depends on carbon distribution within the soil and MINS signal errors.