1. a Former Graduate Research Assistant,Dep. Agronomy , Kansas State Univ. , Manhattan , KS , 66506
2. c Senior author is presently Assistant Professor, Dep. of Agronomy and Soils , Auburn Univ. , Auburn , AL , 3 6849.
3. b Professor,Dep. Agronomy , Kansas State Univ. , Manhattan , KS , 66506