[1] USDA ARS, Crop Sci Res Lab, Mississippi State, MS 39762 USA
[2] Mississippi State Univ, Expt Stn, Pontotoc Ridge Flatwoods Branch, Pontotoc, MS 38863 USA
[3] USDA ARS, Natl Soil Dynam Lab, Auburn, AL 36832 USA
[4] USDA ARS, Dale Bumpers Small Farms Res Ctr, Booneville, AR 72927 USA
[5] USDA ARS, Food Anim Environm Syst Res, Bowling Green, KY 42101 USA