3io 
Journal of Agricultural Research 
Vol. IX, No. 9 
to the conclusion that this latter assumption is not the correct one. 
Hence, the quantity which has been formed, due to the irrigation water, 
must be larger than is here indicated. The large quantity of nitric 
nitrogen which has disappeared from the unirrigated plot during the 
summer could not have been due to denitrification, for there was noth¬ 
ing in the conditions of this plot which would favor the denitrification, 
the quantity of organic matter present was low, and the aeration would 
be better than in the irrigated soil. The only conditions which could 
in any way favor it are larger quantities of nitrates present, and these 
may favor the rapid growth of other organisms. Furthermore, our re¬ 
sults show the existence of many more organisms in this unirrigated plot 
during the spring than there are in any of the other plots on which pota¬ 
toes were grown. Hence, the most reasonable explanation is that the 
nitrates disappeared because the bacterial flora of the soil had trans¬ 
formed them into proteins in their metabolic processes. 
3.— OAT LAND 
There were four plots in this series and the water applied and method 
of application were the same as in the previous series. The average 
results for the three years are given in Table IX. 
Table IX .—Nitric nitrogen in oat land—Average for three years 
[Results expressed as pounds per acre) 
Plot No. 
Period. 
Water ap¬ 
plied in five 
applications. 
Depth of soil. 
1st foot. 
ad foot. 
3d foot. 
4th foot. 
5th foot. 
6th foot. 
Total. 
Inches . 
43 . 
spring. 
37-5 
13 - 7 
4*3 
5*9 
1.8 
3*4 
2. 6 
3 1 * 7 
44 . 
25. 0 
15. s 
4*9 
3*4 
5*3 
1. 8 
4*3 
35*5 
45 . 
° 
7.6 
6.9 
9.6 
4. 6 
*•7 
3 *o 
33*4 
46. 
None. 
9.1 
5*9 
4. 0 
6. 1 
10. 7 
6.3 
42. 1 
Art . 
Summer. .. 
77. e 
2. 2 
2. 0 
2. 2 
1. 2 
1. 0 
1.8 
12. 1 
tO. 
44 . 
0 1 D 
25.0 
2. 6 
i *7 
0* * 
3*2 
2. 8 
2.4 
3*3 
16. 0 
45 . 
...do. 
I 5 - 0 
5 *i 
3*8 
3*7 
i *7 
3 *o 
.8 
18. 1 
46. 
...do. 
None. 
1. 6 
1. ^ 
1. 6 
1. 6 
.8 
10. 4 
43 . 
Fall. 
37-5 
O * O 
5*6 
3.0 
4.0 
2.8 
2. 5 
2* 5 
v T 
20. 4 
44 . 
25.0 
4.0 
3 * 2 
3 *o 
2*7 
2.8 
2. 6 
18.3 
45 . 
* 5 *o 
4. 2 
3*3 
4. 1 
3*4 
2.9 
2*7 
20. 6 
46 . 
...do. 
None. 
6.7 
3*9 
3*7 
3*3 
2.9 
2.8 
2 3*3 
The nitric nitrogen in all of the oat plots is quite uniform during the 
spring, but by midsummer the large accumulations of the surface foot 
have disappeared. This may be due to the leaching out of the nitrates 
by the irrigation water, or the rapidly growing plant may have utilized 
it. Very likely it is due to the latter factor, for the loss is nearly uni¬ 
form from the irrigated and unirrigated plots. The only change which 
