Eleanor Campbell1, Adriana Silva2, Francisco F. C. Mello2, Carlos E Pellegrino Cerri3, Mark Easter4, Christian Davies5 and Keith Paustian6, (1)Colorado State University, Fort Collins, CO, (2)Center for Nuclear Energy in Agriculture, Piracicaba, Brazil, (3)Department of Soil Science, Luiz de Queiroz College of Agriculture - University of São Paulo, Piracicaba, Brazil, (4)Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO, (5)Shell Technology Center Houston, Houston, TX, (6)Colorado State University, Fort Collins, CO, US