1. Dep. of Soil and Crop Sciences Texas A&M Univ. 370 Olsen Blvd. College Station TX 77843 USA
2. Texas A&M AgriLife Research 600 John Kimbrough Boulevard College Station TX 77843 USA
3. Columbia Plateau Conservation Research Center USDA–Agricultural Research Service 48037 Tubbs Ranch Road Adams OR 97810 USA
4. Texas A&M AgriLife Extension 11708 Highway 70 South Vernon TX 76384 USA