Department of Soils and Plant Nutrition, University of California, Riverside, U.S.A.
2The author is grateful to the following investigators for reading this manuscript and.for many constructive suggestions: T. W. Embleton, W. W. Jones, and W. Reuther, Dept. of Horticultural Science, University of California, Riverside; O. A. Lorenz and K. B. Tyler, Dept. of Vegetable Crops, University of California, Riverside; A. Ulrich, Dept. of Soil and Plant. Nutrition, University of California, Berkeley; A. L. Kenworthy, Dept. of Horticulture, Michigan, State University, East Lansing; F. Fulimer, American Potash Institute, Inc., Los Gatos, California; M. E. McCollam, American Potash and Chemical Corporation, San Francisco, California; P. F. Smith, Agricultural Research Service, USDA, Orlando, Florida; P. Prevot, Institute de Recherches pour les Hulles et Oleagineux, Paris, France; and E. Malavolta, Escola. Superior de Agricultura, Piracicaba, Brazil.
1Following the preparation of this paper, a somewhat similar effort by Dr. A. L. Kenworthy, Dept. of Horticulture, Michigan State University, East Lansing, came to the author's.attention. In the case of plants covered by both Dr. Kenworthy and me, there is substantial.agreement in most instances. In a few cases where my suggestions differ from those of Dr. Kenworthy's, his method (by mutual agreement) has been included herein as an alternate.
