1. Agroecosystem Management Research Unit, USDA–Agricultural Research Service (ARS), Lincoln, NE 68583, USA.
2. Soil Management and Sugarbeet Research Unit, USDA-ARS, Fort Collins, CO 80526, USA.
3. Wheat, Sorghum, and Forage Research Unit, USDA-ARS, Lincoln, NE 68583, USA.
4. National Soil Survey Center, USDA–Natural Resources Conservation Service, Lincoln, NE 68508, USA.