|Rogers Jr, Hugo|
|Torbert, Henry - Allen|
|Prior, Stephen - Steve|
Submitted to: ASA-CSSA-SSSA Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 7/2/2003
Publication Date: 11/2/2003
Citation: Wielopolski, L.,Rogers, H.H., Torbert, H.A., Prior, S.A., Denton, H.P., and Tyler, D.D. 2003. Non-Destructive Determination of Soil Carbon in Large Fields. In Agronomy Abstracts, ASA, Madison, WI [CD-ROM computer file].
Technical Abstract: Monitoring of soil carbon content is important for determining the effect of management practices on soil quality and carbon sequestration. Standard methods are laborious and intrusive. A need exists for a rapid, noninvasive method of soil carbon measurement. It is proposed to use gamma ray spectroscopy following inelastic neutron scattering (INS) from carbon. For that purpose fast, 14 MeV, neutrons produced by a neutron generator are directed into the soil and the induced 4.44 MeV gamma ray emission from the excited carbon nuclei is measured with NaI detectors located on the soil surface. This is a non-invasive in situ method to quantitatively measure soil carbon in large volumes. The three step process of neutron penetration, inelastic scattering, and gamma ray detection are very fast; neutrons move at speeds of about 5 cm/ns, inelastic scattering and subsequent emission of a gamma ray occurs in few pico-seconds or less, and the gamma ray travels at the speed of light. Since at these time intervals a movement of an INS system at a speed of 5 to 10 mph, or faster, can be considered stationary this allows use of an INS system in a stationary or scanning mode. Following initial calibration in sand the validity of the methods was confirmed at three sites with concurrent soil chemical analysis. There was a good agreement between these two methods.