Received for publication October 7, 1968. Contribution from the Soil and Water Conservation Research Division, Southern Plains Branch, Agricultural Research Service, USDA, in cooperation with the Kansas Agricultural Experiment Station. Department of Agronomy Contribution No. 1054 and Department of Horticulture and Forestry Contribution No. 429.
Research Soil Scientist, USDA; Engineering Research Technician, USDA; Associate Professor, Horticulture and Forestry Department, Kansas State University, respectively.