1. USDA‐ARS-JPCNRCC Watkinsville GA 30677
2. Dep. of Crop and Soil Sci. Univ. of Georgia Athens GA 30602-7274
3. USDA‐ARS-GRL El Reno OK 73036
4. USDA‐ARS-NGPRL Mandan ND 58554
5. USDA‐NRCS-ITC Fort Collins CO 80526-8121
6. Dupont Research Wilmington DE 19898
7. Biol. and Agric. Eng. Dep. Univ. of Georgia Griffin GA 30223-1797