1. Assistant Research Scientist, Dept. of Soil, Water, and Environmental Sciences, 429 Shantz Bldg. 38, Univ. of Arizona, 1200 E. Campus Dr., Tucson, AZ 85721.
2. Institute of Soil, Water and Environmental Sciences, ARO-Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel; formerly, Research Associate, Dept. of Hydrology and Water Resources, Univ. of Arizona, Tucson, AZ 85721.
3. Professor, Dept. of Soil, Water, and Environmental Sciences, 429 Shantz Bldg. 38, Univ. of Arizona, 1200 E. Campus Dr., Tucson, AZ 85721.
4. Professor, Dept. of Soil, Water, and Environmental Sciences and Director, Yuma Agricultural Center, Univ. of Arizona, 6425 W. 8th St., Yuma, AZ 85364.