x Preface 



at the time the University was making plans for celebrating its cen- 

 tennial during the year 1948-1949, and in this connection it was serving 

 as host to a number of symposiums. Fortuitously, this one in Madison 

 was a "natural." 



In arranging the program, the Committee made an attempt to pro- 

 vide a logical sequence of papers, starting with the soil — the natural 

 source of mineral nutrients — and then treating successively the subjects 

 of entry and translocation of mineral nutrients in plants, the role of 

 minerals in plant nutrition, and finally such modifying influences as 

 light and soil moisture. Two special papers on more practical aspects 

 of the subject were included. Although it was, of course, not possible 

 to treat all phases of this rather broad subject, and many gaps were 

 necessarily left, yet the up-to-date information provided by the con- 

 tributors, all of whom are actively engaged in research, will be of 

 special interest and value to many teachers and investigators, as well as 

 to others concerned with the practical applications. One of the primary 

 objectives of the symposium was to provide an opportunity for presen- 

 tation of latest views regarding the availability of mineral nutrients in 

 soils and mechanisms of absorption and translocation of these mineral 

 nutrients by plants. The papers on these topics should be of special in- 

 terest. 



The necessary financial support was provided through funds of the 

 Wisconsin Alumni Research Foundation administered by the Graduate 

 School of the University of Wisconsin and by a special grant from the 

 National Fertilizer Association. Grateful acknowledgement is made 

 to these sponsors and to all who took part in the program and served 

 on committees. Especial thanks are due to Drs. L. E. Englebert, 

 Gerald C. GerlofT, and Folke Skoog for invaluable help in reading 

 proof. 



Madison, Wisconsin EMIL TRUOG 



September 15, i%i. 



