1. USDA-ARS Soil Drainage Research Unit; 590 Woody Hayes Dr., Rm. 234 Columbus OH 43210
2. School of Natural Resources, Ohio State Univ.; 2021 Coffey Rd., 210 Kottman Hall Columbus OH 43210
3. Biosystems and Agricultural Engineering Dep.; Oklahoma State Univ.; 109 Agricultural Hall Stillwater OK 74078