viii PREFACE 



The present volume is intended as a text and reference 

 work for students of soils and others interested in arid 

 agriculture. It should find wide use by county agricul- 

 tural agents and the better trained farmers in regions 

 where the alkali problem is encountered. 



References are given in connection with each chapter. 

 The figures in parenthesis in the body of the text indicate 

 the number of the reference at the end of the chapter. 

 No attempt has been made to cite all the literature, but 

 most of the important papers are included. Foreign titles 

 have usually been translated into English in order to make 

 them clearer to the general reader. Where the original 

 article is likely to be unavailable an attempt has been 

 made to refer to an abstract in some available publication 

 such as the Experiment Station Record. 



The author wishes to acknowledge his indebtedness to 

 all who have contributed either directly or indirectly to 

 the work. He has drawn freely from all available sources, 

 but he is particularly indebted to Dr. E. W. Hilgard and 

 his associates in California and to the workers in the Bureau 

 of Soils, U. S. Department of Agriculture. These two 

 sources of information have proved to be veritable "gold 

 mines." 



The following who have read part or all of the manu- 

 script have given many valuable suggestions: Doctors 

 J. E. Greaves, E. G. Peterson, F. L. West, Willard Gardner, 

 and G. R. Hill, Jr., and Professors George Stewart, O. W. 

 Israelsen, D. W. Pittman, M. D. Thomas, Mrs. B. C. 

 Pittman, and Mr. K. B. Sauls. 



The author also wishes to express his appreciation to 

 the several assistants and co-workers who have helped in 

 his experiments with alkali during a number of years. 

 Without the faithful and efficient services of these men the. 



