1. a Cereal Research Institute , P.O. Box 391, Szeged , H‐6701 , Hungary
2. b Department of Agronomy , Oklahoma State University , Stillwater , OK , 74078
3. c USDA‐ARS , Environmental Chemistry Laboratory , Beltsville , MD , 20705–2350
4. d USDA‐ARS , Appalachian Soil and Water Conservation Research Laboratory , Beckley , WV , 25802–0867