July i6, 1917 Movement and Distribution of Moisture in Soil 133 



top sections in quantities corresponding to irrigations of 5, 8.66, and 15 

 inches. Surface evaporation was prevented by covering the open ends. 

 To determine the moisture in the different sections, the sets were taken 

 down I, 2, 3, 5, and 10 days after the application of water. 



These results are recorded in figures 15 and 16. It will be noticed 

 from figure 15 that during the 10 days after the application of an 8.66- 

 inch irrigation a considerable amount of moisture was drawn from the 

 section receiving the water into the lower sections for every initial per- 

 centage. The two lower sections of the soil with 2)4 per cent of moisture 

 and the sixth section of the 5 per cent soil had not been changed after 

 standing i o days. The most rapid downward movement, as indicated by 



Perce n tjge of moii tui-e in joil cftsr downv/ard movement for various pencdi 



S- e 





Fig. 



fnifiaL mcjsfur'c ^'^^ 



lt> ill JO 



^To 



ln;t't!l mo'slunt 10% 



{nitioi moisture 15' 



/niT/at moisture S0% 



-Diagram showing the effect of the initial percentage of moisture and time on the downwa»d 

 movement of water after an 8.66-inch irrigation. 



the increase in moisture in the lower sections, is found in the soil having 

 the greatest initial moisture content. 



The figure shows practically no difference in the percentage of water in 

 the soils wnth a high initial percentage of moisture after lo days, but there 

 was a marked difference in the drier columns of soil. 



In figure i6 is presented the average distribution of moisture in the 

 first lo days after irrigation. It will be noticed from the figure that with 

 an increase in initial percentage above 5 per cent there was a very rapid 

 increase in the depth of penetration, the increase being most marked in 

 the columns receiving the largest application of water. 



In the drier soils the larger irrigation increased the moisture of the top 

 sections more than the smaller, but the difference was not so noticeable 

 in the soils having a 20 per cent initial content. This can readily be 



