1. Dep. of Crop and Soil Sciences; P.O. Box 646420, Washington State Univ. Pullman WA 99164-6420
2. USDA-ARS; Land Manage. and Water Conserv. Res. Unit; 215 Johnson Hall, Washington State Univ. Pullman WA 99164-6421
3. John Deere Agri Services; 3665 JFK Pkwy. Fort Collins CO 80525