Vlll PEEFACB 



The book now offered is the first attempt to 

 assemble and organize the known facts of science 

 in their relation to the profitable production of 

 plants, without urigation, in regions of limited 

 rainfall. The needs of the actual farmer, who 

 must understand the principles before his practices 

 can be wholly satisfactory, have been kept in view 

 primarily ; but it is hoped that the enlarging group 

 of dry-farm investigators will also be helped by 

 this presentation of the principles of dry-farming. 

 The subject is now growing so rapidly that there 

 will soon be room for tAvo classes of treatment: 

 one for the farmer, and one for the technical 

 student. 



This book has been written far from large 

 libraries, and the material has been drawn from 

 the available sources. Specific references are not 

 given in the text, but the names of investigators 

 or institutions are found with nearly all state- 

 ments of fact. The files of the Experiment Station 

 Record and Der Jahresbericht der Agrikultur 

 Chemie have taken the place of the more desirable 

 original publications. Free use has been made 

 of the publications of the experiment stations and 

 the United States Department of Agriculture. 

 Inspiration and suggestions have been sought and 

 found constantly in the works of the princes of 

 American soil investigation, Hilgard of California 



