1. USDA‐Agricultural Research Service (ARS), National Laboratory for Agriculture and the Environment (NLAE) 2110 University Boulevard Ames IA 50011‐3120
2. USDA‐ARSAgroecosystem Management Research Unit, 316 Biochemistry Hall, Univ. of Nebraska East Campus Lincoln NE 68583‐0938
3. USDA‐ARS, North Central Soil Conservation Research Lab 803 Iowa Avenue Morris MN 56267
4. USDA‐ARS, Soil & Water Management Research Unit, Univ. of Minnesota 439 Borlaug Hall, 1991 Upper Buford Circle St. Paul MN 55108
5. USDA‐ARS, North Central Agricultural Research Laboratory 2923 Medary Avenue Brookings SD 57006
6. USDA‐ARS, Coastal Plains Soil, Water, and Plant Research Center 2611 West Lucas Street Florence SC 29501
7. USDA‐ARS, USDA‐ARS‐Pasture Systems and Watershed Management Research Unit Bldg 3702 Curtin Road University Park PA 16802
8. Department of Crop and Soil Sciences Pennsylvania State University University Park PA 16802
9. Department of Agricultural and Biosystems Engineering Iowa State University Ames IA 50011