3°6 
Journal of Agricultural Research 
Vol. IX, No. 9 
Table IV .—Average yield of dry matter and nitrogen from the experimental plots on 
Greenville farm 
[Expressed as pounds per acre] 
Water applied. 
Alfalfa. 
Potatoes. 
Plot No. 
Hay. 
Nitrogen. 
Plot No. 
Tubers. 
Nitrogen. 
Inches. 
37*5 . 
3 i 
IO, 464 
282. 5 
35 
1,464 
20. 4 
25. 0. 
32 
9 , 963 
265. 0 
36 
1,540 
24. 8 
15-0. 
33 
9 , 779 
259 - 1 
37 
i ,759 
33-2 
None. 
34 
6, 808 
170. 1 
38 
1,075 
19.1 
Oats. 
Corn. 
Water applied. 
Plot 
No. 
i Grain. 
Straw. 
Nitrogen. 
Plot 
No. 
Grain. 
Stover. 
Nitrogen. 
Inches . 
37*5 . 
43 
2,27 3 
2,989 
89.5 
47 
2, 080 
3.316 
66.3 
25.0. 
44 
2.093 
2,581 
83.9 
48 
1,995 
3.332 
69. 6 
15*0 .. 
45 
1,885 
1, 821 
1, 928 
71.7 
49 
2,179 
3.605 
76. 6 
None... 
46 
1,560 
64. 0 
50 
1, 600 
3.280 
62. 3 
INFLUENCE OF WATER ON THE NITRIC NITROGEN OF THE SOIL 
The results obtained by a direct determination of the nitric nitrogen 
of the soil have been so arranged that the plots growing each specific 
crop but receiving different quantities of irrigation water are placed in 
the same table. This makes it possible to directly compare the plots 
receiving varying quantities—37.5, 25, and 15 inches of irrigation water— 
with each other and each of these in turn with the unirrigated plot. 
The results are reported as pounds per acre and are the average for three 
years. The plots were sampled in the spring (May 1), midsummer (Au¬ 
gust 1), and in the fall (November 28). 
1.—alfalfa land 
There were four plots in this series, one receiving 37.5 inches of irrigation 
water, one 25 inches, one 15 inches, and one was unirrigated. The aver¬ 
age results expressed as pounds per acre are given in Table V. 
During the spring and summer the nitric nitrogen is about uniformly 
distributed throughout the 6 feet of soil, but in the fall it has become 
concentrated in the surface 2 feet. The difference in the nitric-nitrogen 
content of the soil of the various plots between fall and spring is quite 
significant, for the plots which had received no irrigation water through¬ 
out the season are richer in nitric nitrogen in the spring than in the fall, 
while all of the irrigated plots are much richer in the fall than in the 
spring. This is likely due to the moist conditions of the irrigated plots 
in the fall, as the winter rains would carry the soluble constituents of 
