1. Mississippi State Univ.; Delta Research and Extension Center; 82 Stoneville Rd. Stoneville MS 38776
2. USDA-ARS, National Sedimentation Laboratory, Water Quality and Ecology Research Unit; 598 McElroy Dr. Oxford MS 38655
3. Helena Chemical Company; 424 Quail Crest Dr. Collierville TN 38017
4. Mississippi State Univ.; Dep. of Plant and Soil Sciences; Box 9555 Mississippi State MS 39762