Mar. x, 1924 
Movement of Water in Irrigated Soils 
659 
placed in the tube and the soluble material was presumably distributed 
evenly throughout the mass. In the field where water is lost by evapora¬ 
tion from the surface layer of soil there is usually found an accumulation of 
soluble material at or near the surface. When water is applied this passes 
into solution and moves downward with the water. 
In order to approximate these field conditions somewhat more closely 
another experiment was set up. The soil used was a permeable sandy 
loam from the Newlands reclamation project in Nevada. The leaching 
was done in glass pots, like the one shown in figure 4. Four pots were 
used, each containing 200 gm. of soil. The soil was first moistened 
thoroughly and allowed to stand for some time to establish conditions of 
equilibrium between the solution and the soil. Each pot was then 
treated with 1 gm. of sodium chlorid which was mixed into the moist 
surface soil so that it might go into solution. The soil was then 
leached by adding 10 cc. of distilled water to each pot. The percolate 
from each leaching was collected below and analyzed, with the results 
shown in Table XXI. 
Table XXI .—Effect on the balance of the constituents of diluting the soil solution by 
leaching, the total salt being expressed as percentage of the solution and the constitu¬ 
ents as percentage of reacting values based on the total acids 
Leaching No. 
Total 
salts.® 
Percentage of reacting values. 
rCa. 
rHCOs. 
r CL 
r SO4 
0. 295 
33-4 
6.8 
2-3 
91. 0 
2 . 
i- 525 
34 - 6 
i- 7 
80.3 
18. 0 
3 . 
1. 600 
33*2 
.8 
80. 0 
19. 2 
2. 160 
3°-4 
.6 
86. 7 
12. 7 
5 . 
1. 840 
29.4 
• 7 
87-3 
12. 0 
6 . 
575 
29.4 
.8 
86.7 
12. 5 
7 . 
1. 440 
29. 7 
1. 0 
85.2 
13.8 
S . 
1.185 
24.5 
1. 2 
83.1 
x 5 - 7 
9 . 
•905 
21. 6 
i- 5 
80. 0 
18. 5 
10. 
• 725 
i 3 - 3 
3-6 
75-2 
21. 2 
11. 
. 600 
x 5 - 5 
3 - 1 
72. 6 
24-3 
12. 
. 480 
12. 4 
5-5 
69. 0 
25- 5 
13 . 
• 340 
10. 1 
ii *3 
67- 5 
21. 2 
14 . 
■ 265 
&5 
11. 8 
64. 6 
23. 6 
*5 . 
. 230 
“•5 
20. s 
60. 2 
x 9-3 
• i 95 
8.9 
23. 2 
60. 2 
16.6 
... 
• 150 
8.7 
33-4 
54-2 
12. 4 
18. 
. 127 
7-3 
34-2 
56. 2 
9.6 
a Determined by electrical resistance. 
While the ratio of water to soil for each fraction of the percolate was 
the same in this experiment as in the preceding one, the rate of leaching 
was different in that each successive application of water was made 
only after percolation from the previous application had ceased. Often 
the pots stood overnight between leachings, so that diffusion tended to 
equalize the distribution of the solution constituents and retard the 
rate of displacement. These conditions resulted in a much slower rate 
of decline in the concentration of the successive percolates than that 
shown in the preceding experiment. 
The addition of the sodium chlorid to the solution at the beginning 
of the experiment also caused some significant changes in the solution. 
