1. Research Associate, Texas AgriLife Research, Texas A. & M., 2415 E. Business Hwy. 83, Weslaco, TX 78596 (corresponding author).
2. Research Hydraulic Engineer, USDA-ARS Arid Land Agricultural Research Center, 21881 N. Cardon Lane, Maricopa, AZ 85238.
3. Agricultural Engineer, USDA-ARS Arid Land Agricultural Research Center, 21881 N. Cardon Lane, Maricopa, AZ 85238.
4. Soil Scientist, USDA-ARS Arid Land Agricultural Research Center, 21881 N. Cardon Lane, Maricopa, AZ 85238.