1. Extension Irrigation Engineer, Washington State Univ., 24106 N. Bunn Rd., Prosser, WA 99350. E-mail: troy_peters@wsu.edu
2. Soil Scientist, Soil and Water Management Research Unit, USDA-ARS, P.O. Drawer 10, Bushland, TX 79012. E-mail: srevett@cprl.ars.usda.gov