326 
Journal of Agricultural Research 
Vol. IX, No. 9 
The number of organisms in the corn soil is highest in summer and 
lowest in the fall. But during spring and fall there would appear to be 
no relationship between the water applied and number of organisms. 
However, in the summer there is a very pronounced difference in favor 
of the plots receiving the greatest quantity of water, and this regularity 
is found in each season's results. 
The results obtained for ammonification are very irregular, but it 
is interesting to note that they in every case have almost a quantitative 
relationship to the results obtained with the potatoes. 
Nitrification is slightly higher in the summer than during either of 
the other seasons, and it would appear that the irrigation water had 
increased the nitrifying powers. 
fallow soil 
The fallow plots received the same quantity of water as the cropped 
plots and were plowed and handled the same. Any weeds which 
appeared during the summer were pulled. The average summarized 
results for the three years are given in Table XXVI. 
Table XXVI .—Number of colonies of bacteria , milligrams of ammonia, and milligrams 
of nitric nitrogen from soil receiving varying amounts of water . Crop, fallow. Aver¬ 
age for three years 
NUMBER OF COLONIES DEVELOPED IN 4 DAYS ON SYNTHETIC AGAR PER GRAM OF SOIL 
Plot No. 
Water 
applied. 
Sampled 
May 1. 
Sampled 
Aug. 1. 
Sampled 
Nov. 38. 
Average. 
39 . 
Inches . 
37 - 5 
8, 266, OOO 
6,933,000 
2, 200,000 
5, 800,000 
40 . 
25.0 
3,300,000 
4, 867, OOO 
3,370,000 
3,967,000 
3, 700, OOO 
3 > 457 * 000 
3,789,000 
4 i. 
xr 15 * 0 
2, 533 > 000 
I, 767,000 
42 . 
None. 
3, IOO, OOO 
3,633,000 
2,833,000 
MILLIGRAMS OF 
AMMONIA PRODUCED IN IOO GM. OF SOIL IN 4 
DAYS 
39 . 
37-5 
66.2 
69.4 
49.6 
6l. 7 
40 .. • 
25.0 
66.8 
80.1 
56.1 
67.7 
41 .. 
15.0 
61. 5 
76.8 
46. s 
61. 6 
42 .. 
None. 
61. 2 
56- 7 
52. 6 
56.8 
MILLIGRAMS OF NITRIC NITROGEN PRODUCED IN IOO GM. OF SOIL IN 
21 DAYS. 
39 ■ *. 
37 - S 
x. 5 
8.7 
1.1 
3-7 
40 . 
25.0 
. 6 
2. O 
1-5 
i -3 
41 . 
42 . 
i 5 -° 
None. 
i- 5 
1. 6 
3-6 
7-7 
3-1 
4.2 
2.7 
4 - 5 
