1. Dep. of Plant and Soil Sciences Research and Education Center, Univ. of Kentucky 1205 Hopkinsville St. Princeton KY 40546‐0091
2. Dep. of Biosystems Engineering and Environmental Sciences West Tennessee Research and Education Center, Univ. of Tennessee 605 Airways Blvd. Jackson TN 38301
3. Dep. of Biosystems Engineering and Environmental Sciences Univ. of Tennessee 2506 E. J. Chapman Drive Knoxville TN 37996‐4531
4. Dep. of Soil Science North Carolina State Univ. 1F Holladay Hall Raleigh NC 27695
5. Dep. of Animal Sciences Univ. of Tennessee 2505 River Dr. Knoxville TN 37996‐4574