1. a Department of Environmental Studies (Soil Science) , The Union Institute , Cincinnati , Ohio , USA
2. b Department of Agricultural Engineering/Irrigation Science , Cal-Poly University , Pomona , California , USA
3. d Modern Irrigation Co. , Upland , California , USA
4. c Department of Agricultural Sciences (Soil Science and Plant Nutrition) , UCLA , California , USA
5. e Wallace Laboratory , El Seguendo , California , USA