1. North Carolina Cooperative Extension Vernon G. James Research Center 207 Research Station Plymouth NC 27962 USA
2. Crop and Soil Sciences Dep. North Carolina State Univ. Williams Hall, 101 Deriex Raleigh NC 27607 USA
3. Crop and Soil Sciences Dep., Vernon G. James Research Center North Carolina State Univ. 207 Research Station Plymouth NC 27962 USA