352 
Journal of Agricultural Research 
Vol. VIII, No. 9 
Table VI. —Effect of irrigation water on the nitrates in cropped and uncropped soil. 
Average of all manure treatments for three years 
[Results expressed as p. p. m. of sodium nitrate] 
Water applied. 
Depth (feet). 
None. 
5 inches. 
10 inches. 
20 inches. 
30 inches. 
40 inches. 
Average. 
Cropped. 
Fallow. 
Cropped. 
Fallow. 
Cropped. 
Fallow. 
Cropped. 
Fallow. 
Cropped. 
£ 
Cropped. 
Fallow. 
1 
Fallow. 
1. 
20.8 
56-2 
1 . 7-2 
63.6 
18.8 
48.1 
14. 7 
29.6 
17. 2 
31-3 
10. 7 
22.4 
16.6 
4 i -9 
2. 
16.6 
44.0 
11*3 
51-7 
13-3 
39-6 
9 -S 
29-3 
9.9 
28.1 
9-1 
19.0 
11. 6 
35 - 3 
3 . 
12*5 
40.0 
12.3 
42. 0 
12. 7 
37 -o 
7 - 7 
25-3 
7 -S 
3 i-1 
4-4 
21.0 
9 - 5 
32-7 
4 . 
16.6 
41.0 
12.9 
41. 0 
IS -1 
40-5 
8.7 
3 i *7 
7-7 
25 -S 
4-2 
16.9 
10. 9 
32.8 
5 . 
17.2 
45-6 
10.9 
37-3 
9.9 
32-9 
7-9 
38-9 
S -7 
20.4 
7*2 
15-8 
9-8 
31-8 
6. 
IS-8 
45-0 
10. s 
46. 7 
8.9 
38- 2 
8.1 
38.1 
7 -i 
29.1 
6.9 
19.4 
9 -S 
36.1 
7 . 
12.9 
47 -1 
ii -3 
38-0 
9.9 
32-3 
9.4 
32-3 
9-9 
30-1 
9 -S 
18.0 
10. 5 
33-0 
8. 
13-9 
38.4 
12.9 
33-3 
10. 3 
27. 7 
9-5 
27. 7 
10.3 
23-3 
6.5 
22.4 
10.6 
28.8 
9 . 
11. 7 
28. 9 
Ii.9 
28. 9 
10. 7 
23-8 
8.1 
27 - S 
9 - S 
24.9 
7-7 
19. 6 
9*9 
25-6 
10. 
9-3 
37-4 
Ii. 1 
40. 0 
13-9 
28. 7 
8.6 
26.6 
8.7 
25-3 
5-9 
17.6 
9.6 
29-3 
Average. 
14.7 
42*5 
12. 2 
42-3 
12.3 
34-7 
9.2 
30.8 
9-4 
26.9 
7.2 
19. 2 
10. 8 
32.7 
RELATION OR PERCENTAGE OP WATER TO TOTAL SALTS AND NITRATES 
To show the average effect of water applied, manure applied, and 
depth of soil on the moisture, total soluble salt, and nitrate content 
gJgPerCent Water ggjRPM.Total Salts ^RPM. NaWOj 
Fig. 13.—Graph showing effect of irrigation water on nitrates, total soluble salts, and percentage of mois¬ 
ture in cropped soil at the close of the cropping season. Average for all manuring treatments during 
three years to a depth of 10 feet. 
of the soil, figures 13, 14, 15, 16, and 17 have been prepared. Some of 
the conclusions that might be drawn from these averages would not be 
substantiated when the factors influencing them were considered sepa¬ 
rately. 
