1. School of Natural Resources, 302 Anheuser-Busch Natural Resources Building, Univ. of Missouri; Columbia MO 65211 USA
2. Dep. of Desertification Combat; College of Agricultural Engineering Sciences, Univ. of Baghdad; Baghdad Iraq
3. The Center for Agroforestry, 203 Anheuser-Busch Natural Resources Building; Univ. of Missouri; Columbia MO 65211 USA
4. USDA-ARS Cropping Systems and Water Quality Research Unit; Columbia MO 65211 USA