BB8BS 



UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 835 



Contribution from the Bureau of Public Roads 

 THOMAS H. MACDONALD, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



August 6, 1920 



CAPILLARY MOVEMENT OF 

 SOIL MOISTURE 



By 

 WALTER W. McLAUGHLIN, Senior Irrigation Engineer 



CONTENTS 



Page 



Object 2 



Plan of Experiments 2 



Hate and Extent of Movement of Soil 



Moisture by Capillarity 13 



Effect of Gravity on the Movement of 



Soil Moisture by Capillarity .... 39 



Evaluation of Empirical Curves , . . , 47 



Open Versus Covered Flumes .... 54 

 Effect of Temperature on Soil-Moisture 



Conditions 56 



The Capillary Siphon 58 



Capillary Movement of Moisture From a 



Wet to a Dry Soil 63 



References 69 



WASHINGTON 

 GOVERNMENT PRmiTNG OFFICE 



1920 



