Some earlier work (Romney et al., 1970) raised concern that Pu may become more available with passing time under continued cropping conditions. In order to further investigate this problem and the comparable fate of Am, long-term - cropping experiments are under way with these fallout area soils being cropped with alfalfa and native desert plants. ACKNOWLEDGMENTS This work was conducted under Contract E (04-1) GEN 12 between the United States Energy Research and Development Administration and the University of California. Supplemental support for sample preparation, radiochemical analysis, and data reduction was funded by the Nevada Applied Ecology Group, Bioenvironmental Sciences Division, USERDA Nevada Operations Office. 63