1. Dep. of Soil Science; North Carolina State Univ., Vernon G. James Research and Extension Center; 207 Research Station Road Plymouth NC 27962
2. USDA-ARS; National Sedimentation Lab.; P.O. Box 1157 Oxford MS 38655
3. Agronomy Dep., Louisiana Agric. Exp. Stn.; Louisiana State Univ. Agricultural Center; Baton Rouge LA 70803
4. Dep. of Agronomy; Ohio State Univ.; Columbus OH 43210