1. USDA-ARS Cropping Systems and Water Quality Research Unit, 241 Agricultural Engineering Building; Univ. of Missouri; Columbia MO 65211
2. Dep. of Agronomy, 2004 Throckmorton Plant Sciences Center; Kansas State Univ.; Manhattan KS 66506
3. Division of Plant Sciences, 108 Waters Hall; Univ. of Missouri MO 65211
4. The Center for Agroforestry, Anheuser-Busch Natural Resource Building; Univ. of Missouri; Columbia MO 65211
5. Dep. of Agriculture; 204 B Albertson Hall, Fort Hays State Univ.; Hays KS 67601
6. Dep. of Soil, Environmental and Atmospheric Sciences, 302 Anheuser-Busch Natural Resource Building; Univ. of Missouri; Columbia MO 65211
7. Southeast Agricultural Research Center; Kansas State Univ.; Parsons KS 67357
8. Agricultural and Biosystems Engineering, 4354 Elings Hall; Iowa State Univ.; Ames IA 50011
9. former address, Biological Systems Engineering Department; Univ. of Nebraska; Lincoln NE 68583
10. Dep. of Agronomy; Iowa State Univ.; Ames IA 50011
11. Dep. of Agronomy and Horticulture; 369 Keim Hall, Univ. of Nebraska; Lincoln NE 68583