CAPILLARY MOVEMENT OF SOIL MOISTURE. 



33 



•WATER USED. 



Table 19. — Water used, by -days, \ 

 percentages of total use in 30 days. 



The figures in the small circles show in liters the water used by 

 these flumes. The water used by flumes inclined downward is, like 

 the movement of the moisture, greater than for the horizontal or 

 vertical flumes. A striking feature is the rather uniform use of a 

 comparatively constant quantity of water after the second or third 

 day. The rate of use is more constant and uniform than for the 

 vertical or horizontal flumes. Flume 34 had used on the tenth day 

 about 4 liters of water; on the twentieth day about 8 liters; on the 

 thirtieth day about 11.5 liters; and on the fortieth day about" 14 

 liters. In flume 54 with the heavy Whittier soil an even greater 

 uniformity is observed. In this flume there was used approximately 

 the same quantity of water every day after the sixth day up to the 

 fifty-seventh day, or at the end of the experiment. The same 

 uniformity is found, in fact, in 

 nearly all of the other flumes. 

 One fact worth special notice is 

 that the use of water by the flume 

 as represented by the loss of 

 water from the tanks is that 

 evaporation does not appear to 

 have varied the use to any ex- 

 tent. This is true though the 

 same flume was exposed to al- 

 most all the different and vari- 

 able weather conditions found at 

 Eiverside. To show the relative 

 uniformity in the rate of use of water b}^ some of these flumes 

 Table 19 has been prepared. 



Table 19 shows that the heavier soils use relatively more water 

 at the commencement than near the end of the experiment. It shows, 

 also, a more uniform use by the heavier soils. It shows, for instance, 

 that the soil in flume 54 had used relatively more than twice as much 

 water as any other flume at the end of the first day, while on the fif- 

 teenth day it had used relatively only about one-fifth more than the 

 others. Table 20 shows the amount of water required at different 

 periods of time to advance the moisture in the flumes an average dis- 

 tance of 1 inch. For instance, on the third day, flume 24 had used 

 18 liters of water and the moisture had advanced 44.15 inches, or an 

 average of 479 cubic centimeters of water was required per inch. 



A comparison of the figures in Table 20 with the moisture equiva- 

 lents of the soils appears to show no close relation. However, in a 

 general way the greater the moisture equivalent the greater the 

 quantity of water required to advance the moisture 1 inch. It is ob- 

 147697°— 20— Bull. S35 3 







Flumo. 





Numtev 

 of days. 





















2-1 



:i 





CI 





Per ce~t. 



Percent. 



Per cent. 



Per cert. 



1 



9 



22 



10 



11 



3 



18 



35 



19 



20 



5 



23 



43 



25 



:s 



10 



39 



0/ 



41 



43 



15 



54 



C8 



00 



57 



20 



71? 



78 



C8 



70 



30 



100 



100. 



100 



100 



40 

 50 



121 



127 

 149 



129 













