VI 



Preface 



cations of soil microbiology to other fields of knowledge, especially 

 soil formation and plant nutrition. It should not be considered a 

 reference book, but rather a textbook. No attempt has been made 

 to give complete bibliographies. Appended to each chapter, how- 

 ever, are references to some of the more important papers and books 

 available in the English language, where the student and general 

 reader can find up-to-date, concise statements concerning the prob- 

 lems discussed in the respective chapters and dealing with the various 

 phases of soil microbiology. 



This book follows along the general lines of two previous volumes, 

 Principles of Soil Microbiology (Williams & Wilkins Co., 1st Ed., 

 1927; 2nd Ed., 1932) and The Soil and the Microbe (John Wiley & 

 Sons, 1931). I have drawn heavily upon the texts as well as upon 

 the tables and illustrations of these earlier publications. This book 

 may, therefore, be looked upon as a logical outgrowth of the older 

 volumes, standing midway between the one that was more detailed 

 and the other that was more concise and even more elementary. 



In the preparation of this book, no attempt was made to cover in 

 a comprehensive manner every aspect of the subject of the micro- 

 organisms inhabiting the soil, or of the various processes for which 

 they may be responsible, or of the importance of these in soil fer- 

 tility. It may even appear to some of those who will read this book 

 that some aspects of the subject are treated rather sketchily, whereas 

 others are discussed in great detail. This was bound to be so in a 

 book covering such a vast subject as the complex microbiological 

 population of the soil and its role in soil fertility and plant growth. 

 My intention was to present here a broad outline of the subject, one 

 might even say a philosophy of soil microbiology. The supplemen- 

 tary books and papers recommended at the end of each chapter will 

 help to fill the gaps and suggest additional sources of information 

 on the various aspects of the subject to those who are eager to enlarge 

 upon the information supplied in this \'olinTie. 



Selman a. Waksman 



Neiv Brunswick, New Jersey 

 June, 1952 



