1. Dep. of Agronomy, Plant Sciences 115Univ. of ArkansasFayettevilleAR72701
2. USDA‐ARSPasture Systems and Watershed Manage, Res. Lab.Curtin RoadUniversity ParkPA16802‐3702
3. USDA‐NRCSSouth National Technical Center, 320 West Way Place, Suite 511ArlingtonTX76018