1. USDA‐ARS Grassland, Soil and Water Research Laboratory 808 E. Blackland Road Temple TX 76502
2. Texas A&M AgriLife Extension Service Department of Soil and Crop Sciences Vernon TX 76384
3. Regenis Corporation 6920 Salashan Pkwy. A‐20, P.O. Box 2708 Ferndale WA 98248
4. WSU Mount Vernon Northwestern Washington Research and Extension Center WSU Center for Sustaining Agriculture and Natural Resources 16650 State Route 536 Mount Vernon WA 98273