66 BULLETIN 835, U. S. DEPARTMENT OF AGRICULTURE. 



Table 45. — Movement of moisture upward and downward, from soils contain- 

 ing an initial moisture content of 15 per cent. 



Time 



in 



days. 



Idaho soil. 



Riverside s 



3il. 



Distance moved. 



"Relation 



of up 

 to down. 



Distance moved. 



Relation 



of up 

 to down. 



Up. 



Down. 



Up. 



Down. 



2 



4 



5 



6 



10 



13 



17 



23 



31 



36 



43 



52 



71 



76 



Inches. 



1.50 

 1.50 



Inches. 



Per cent. 



Inches. 



2.25 



Inches. 

 3.50 



Per cent. 

 64 



2.25 



67 



2.62 

 2.88 

 3.75 



7.25 



7.75 



10. 00 



36 

 37 

 37 



2.30 



3.20 



73 



-3.00 



4.50 



67 



5.75 



13.00 



44 



4.12 

 4.50 

 4. 80 



5.50 

 6.75 

 7.00 



75 

 67 

 68 









6.50 

 6.75 



18.25 

 19.00 



35 

 36 



5.37 

 6.00 

 6. 25. 



S.37 

 9.12 

 9.24 



64 

 66 

 67 





















Table 45 shows by percentage the relation of the upward 

 movement of the moisture to the downward movement. After the 

 first daj 7 or two the relation of the upward movement to the down- 

 ward movement remains rather constant. The table shows the rela- 

 tive rapid rate of movement of moisture the first few days and the 

 slower rate with the lapse of time. If the data in Tables 41 and 42 

 showing the upward and downward movement of moisture in sepa- 

 rate flumes are compared, the same relative relation is found as 

 found in Table 45. 



The above data indicate the part gravity plays in soil-moisture dis- 

 tribution. Generally speaking, the' lighter the soil the less is the up- 

 ward movement of the moisture as compared with the downward 

 movement. It also appears that the greater the percentage of mois- 

 ture the greater the downward movement as compared with the up- 

 ward. 



The limited data above presented, when considered with many 

 others in the original records, would lead to the conclusion that 

 under irrigation much moisture may be carried below the root zone 

 of plants, and that moisture once carried below the root zone of 

 plants will probably not be again brought within the root zone in 

 sufficient quantity to be of material benefit to the crop of that season, 

 and hence will be lost to the plant. 



THE MOVEMENT OF MOISTURE EROM WET TO DRY SOIL IN HORIZONTAL BOXES. 



The capillary movement of soil moisture in a horizontal direction 

 as found in the horizontal boxes is greater in extent than the upward 

 movement in the vertical boxes, but not so great as the downward 

 movement. There are given in Table 46 the results of three tests 



