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Title: Non-destructive system for analyzing carbon in the soil

item Prior, Stephen - Steve
item Rogers Jr, Hugo
item Torbert, Henry - Allen

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/25/2008
Publication Date: 9/1/2008
Citation: Wielopolski, L., Hendrey, G., Johnsen, K., Mitra, S., Prior, S.A., Rogers Jr, H.H., Torbert III, H.A. 2008. Non-destructive system for analyzing carbon in the soil. Soil Science Society of America Journal. 72(5):1269-1277.

Interpretive Summary: Carbon is an essential component of life, and plays a pivotal role in the soil’s fertility and productivity. It is an integral part of the atmospheric-terrestrial carbon exchange cycle mediated by plants. Soil carbon is important in the context of agricultural production (soil stewardship and retention of water and nutrients, and to prevent erosion and maintain good soil structure). It is also important for environmental quality preventing erosion and sedimentation, thus contributing to the maintenance of clean water). It has recently been suggested as a potential way to help mitigate global change through soil carbon storage (after capture by growing plants from the atmosphere). All of these require monitoring and assessment of soil carbon if we are to use the best soil management practices. This paper seeks to develop and test a possible new method to measure soil carbon that is fast and nondestructive (inelastic neutron scattering). The feasibility of the method has been demonstrated, and results are promising.

Technical Abstract: Carbon is an essential component of life, and, in its organic form, plays a pivotal role in the soil’s fertility, productivity, and water retention. It is an integral part of the atmospheric-terrestrial carbon exchange cycle mediated via photosynthesis; furthermore, it emerged recently as a new trading commodity, i.e., “carbon credits”. When carefully manipulated, carbon sequestration by the soil could balance and mitigate anthropogenic CO2 emissions into the atmosphere that are believed to contribute to global warming. The pressing need for assessing the soil’s carbon stocks on local-, regional-, and global-scales, now in the forefront of many researches, is considerably hindered by the problems besetting dry-combustion chemical analyses, even with state-of-the-art procedures. To overcome these issues, we present here a new method based on gamma-ray spectroscopy induced by inelastic neutron scattering (INS). The INS method is in situ, non-destructive, multi-elemental one that can be used in stationary- or continuous-scanning-modes of operation. The results from data acquired from an interrogated soil mass of few hundreds of kilograms to an approximate depth of 30 cm are reported immediately. Our initial experiments have demonstrated well the feasibility of our proposed approach; we obtained a linear response with carbon concentration, and a detection limit between 0.5% to 1% carbon by weight.