1. Dep. of Agric. Engineering Univ. of Florida Gainesville FL 32611
2. Dep. of Agronomy and Soil Science, College of Tropical Agric. and Human Resources Univ. of Hawaii Honolulu HI 96822
3. Dep. of Biological and Agric. Engineering, Georgia Exp. Stn. Univ. of Georgia Griffin GA 30223
4. Dep. of Crop Science Univ. of Guelph Guelph ON Canada N1G 2W1