1. USDA‐ARS, Soil Management and Sugar Beet Research Unit Fort Collins CO 80526 USA
2. USDA‐ARS, Jornada Experimental Range Las Cruces NM 88003‐8003 USA
3. University of Florida, Range Cattle and Education Center Ona FL 33865–9706 USA
4. USDA‐ARS, Soil and Water Management Research Unit St. Paul MN 55108 USA
5. USDA‐ARS, Pasture Systems and Watershed Management Research Unit University Park PA 16802 USA
6. Agriculture and Agri‐Food Canada Agassiz British Columbia V0M 1A0 Canada
7. Dept. Agricultural and Biological Engineering Pennsylvania State University University Park PA 16802 USA
8. USDA‐ARS, Office of National Programs, Natural Resources and Sustainable Agriculture Systems Beltsville MD 20705–5140 USA