1. USDA-ARS, U.S. Arid Land Agricultural Research Center; 21881 N. Cardon Ln. Maricopa AZ 85138
2. Crop and Soil Science Dep.; The Pennsylvania State Univ.; 409 ASI Bldg. University Park PA 16802
3. Texas A&M Univ.-Kingsville; Dep. of Agronomy and Resource Sciences; Kleberg Ag. Bldg. Rm. 118, MSC 228 Kingsville TX 78363
4. U.S. Geological Survey MD-DE-DC Water Science Center; 5522 Research Park Dr. Baltimore MD 21228