1. Agronomy Dep. Univ. of Florida P.O. Box 110965 Gainesville FL 32611 USA
2. Texas A&M AgriLife Research 11708 Highway 70 South Vernon TX 76384 USA
3. Dep. of Soil and Crop Sciences Texas A&M Univ. 370 Olsen Blvd. College Station TX 77843 USA
4. Dep. of Agriculture, Food Science, and Kinesiology Eastern New Mexico Univ. 1500 S. Ave. K Portales NM 88130 USA