Montague W. Demment, University of California, Davis; Milton B. Jones, University of California, Davis; Ganga P. Deo, University of California, Davis; D. Michael Center is Postdoctoral Research Associate, UC Hopland Field Station, Hopland; Martin R. Dally is Staff Research Associate, stationed at the UC Hopland Field Station, Hopland. William A. Williams are Assistant Professor, Agronomist, Staff Research Associate, and Professor, respectively, in the Department of Agronomy and Range Science, University of California, Davis;