312 
Journal of Agricultural Research 
Vol. IX, No. 9 
irrigated plots than from the unirrigated plot. This difference is very 
marked if we compare the results obtained on the plot receiving 37.5 
inches of water, with the plot receiving no water for summer and fall. 
The quantity found in the surface foot of the unirrigated plot is about 
the same in the fall as in the spring, while the irrigated contains less 
than half as much. 
Table XI .—Nitric nitrogen in corn land—Average f^r three years 
[Results expressed as pounds per acre] 
Plot No. 
Period. 
Water ap¬ 
plied (five 
applica¬ 
tions). 
Depth of soil. 
1st foot. 
2d foot. 
3d foot. 
4th foot. 
5th foot 
6th foot. 
TotaL 
Inches . 
47 . 
Spring. . . . 
37 - 5 : 
9. I 
3-4 
3-3 
2. I 
i- 7 
4.2 
23.8 
48 . 
25. 0 
7 * 2 
2-3 
2. 0 
1.9 
1.9 
2. 2 
17*5 
49 . 
. 150 
12.3 
8-5 
4. 1 
2. O 
1. 6 
1.9 
3 °* 4 
50 . 
None. 
12. O 
4. 1 
1.9 
2. 5 
3-4 
3 - 5 
27.4 
47 . 
Summer... 
27*5 
I. 2 
2.9 
8-5 
4. I 
4.0 
1.4 
22. 1 
48. 
...do. 
2C. O 
I. 7 
1. 6 
e. K 
0 
1. 0 
2. 2 
16. 8 
49 . 
v> 
15*0 
1.4 
5-2 
3*7 
O 7 
2. 5 
3*2 
3*3 
i 9*3 
5 °. 
...do. 
None. 
3-3 
3 * 1 
2.9 
2. 6 
3-2 
2. 2 
I 7 * 3 
47 . 
Fall. 
37 - 5 
3 *o 
3-6 
2.7 
2 . O 
2. 7 
2.4 
16. 4 
48 .. . 
25.0 
3-7 
3 *o 
2. 2 
2. 7 
2.4 
3 * 2 
17. 2 
49 .•••• 
*5- 0 
5*8 
2 - 5 
3-2 
3 * 0 
3*2 
3 * 2 
20. 9 
5 °. 
None. 
11. 2 
4.6 
3 - 1 
3*5 
5*0 
5*9 
33*3 
The total quantity found in the various plots in the spring is nearly 
the same as that found in them during the fall. A summarized inven¬ 
tory of the nitrogen removed by the crop, together with that formed in 
the various plots, is given in Table XII. Here we note a decrease in 
the nitrogen removed in the crop, as the water applied increases above 
15 inches. This can be accounted for by the larger quantities of water 
washing the nitric nitrogen beyond the sphere of action of the roots, 
thus making the nitrogen the limiting factor. 
Table XII .—Summary of nitrogen transformations in corn land 
[Results expressed in pounds of nitric nitrogen per acre-inch] 
Character of nitrogen. 
Water applied. 
37.5 inches. 
25 indies. 
15 inches. 
None. 
Nitrogen removed in crop. 
Nitrogen in soil in spring.... 
Nitrogen in soil in fall.;. 
Original soil nitrogen removed. 
Nitrogen formed during season... 
66.3 
23.8 
16.4 
7-4 
58-9 
69. 6 
i 7 * 5 
17. 2 
•3 
69-3 
76.6 
30.4 
20. 9 
9*5 
67. 1 
62.3 
27.4 
33*3 
“ 5-9 
68.2 
