1. North Dakota State University, Department of Soil Science 7680, Fargo, ND 58108, USA
2. North Dakota State University, Department of Agricultural and Biosystems Engineering 7620, Fargo, ND58108, USA
3. National Soil Survey Center, Denney Federal Building, 100 Centennial Mall North, Room 152, MS 41 Lincoln, NE 68508-3866, USA