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1United States Soils Laboratory, United States Department of Agriculture, Beltsville, Maryland
2Soil and Water Conservation Research Division, Agricultural Research Service, United States Department of Agriculture, Beltsville, Maryland
3
Research Soil Scientist and Soil Research Helper.
1
Received March 22, 1965.
2
Contribution from the United States Soils Laboratory, Soil and Water Conservation Research Division, Agricultural Research Service, USDA, Beltsville, Maryland.