1. Assistant Professor, School of Earth, Environmental, and Marine Sciences, Univ. of Texas Rio Grande Valley, Edinburg, TX 78539; formerly, Postdoctoral Research Scholar, Dept. of Soil Science, North Carolina State Univ., Raleigh, NC 27695-7619.
2. Soil Specialist, Division of Soil and Water Conservation, North Carolina Dept. of Natural Resources, 512 N Salisbury St, Raleigh, NC 27604-1148.
3. Professor and Extension Specialist, Dept. of Soil Science, North Carolina State Univ., Raleigh, NC 27695-7619 (corresponding author).