|Prior, Stephen - Steve|
|Torbert, Henry - Allen|
Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 11/5/2007
Publication Date: 11/5/2007
Citation: Wielopolski, L., Brown, D.J., Izaurralde, C.R., Mitra, S., Omonode, R., Prior, S.A., Torbert III, H.A. 2007. Non-Destructive Carbon Measurement in Soil over Large Fields. American Society of Agronomy Meetings. CDROM.
Technical Abstract: Carbon in soil plays a critical role in soil quality and productivity. Changes in soil management practices, as for example switching from conventional till (CT) to no till (NT), precision agriculture, carbon sequestration, and soil carbon stocks required in modeling global warming necessitate extensive quantification of soil carbon burdens on local, regional and global levels. These emerging needs supersede today’s throughput capabilities of the dry combustion (DC) chemical method, which at present is the standard analytical procedure for belowground carbon determination. The DC method is labor intensive, time consuming, provides point information, and requires intensive post-analysis for field predictions. There are three new technologies that, with various degrees of success, overcome the conventional limitations of the DC method. Here we present results obtained with the Inelastic Neutron Scattering (INS) method a new modality that differs fundamentally from the other two in that; 1) It is truly non-destructive, it is mounted about 30 cm above the ground and no soil samples are taken. 2) It has multi-elemental capability with high elemental specificity. 3) It probes large volumes from hundreds of kilograms and up, and 4) it enables stationary and scanning capabilities providing a true mean value for the field carbon content. The last characteristic is possible because of the fast, 10-9 to 10-18 s, processes involved between neutron emission, penetration into the soil, interaction with soil elements stimulating gamma emissions, and detection of gamma rays. It is shown that when fields are fairly homogeneous the scanned values for a field are fairly close to the mean value of the static measurements obtained at various speeds. However, cases are reported in which these values disagree posing the question which one is correct. Is it possible that we missed some low areas during our static sampling?