48 
Journal of Agricultural Research 
Vol. XI, No. * 
Table III. — Effect of variations in depths of column , moisture content, and compactness 
of a soil upon nitrate accumulation 
[Results are expressed as gain or loss in milligrams of NO3 per 100 gm. of soil] 
Sample No.® 
Depth of 
column. 
Sample 
from 
depth of— 
Water per 
100 gm. of 
soil. 
Loose. 
Medium. 
Compact. 
Inches. 
Inches. 
C. c. 
iA. 
5 
0-1 
15 
o -34 
0. 84 
13. 40 
iB. 
5 
4-5 
15 
2. 36 
6. 50 
IO. 70 
2A. 
e 
0—1 
20 
7. 80 
2B. 
D 
5 
4-5 
20 
6. 30 
21. 40 
35 - 70 
31. 6a 
3 A. 
5 
0—1 
3 ° 
76. 50 
25. 80 
-10. 70 
3 B . 
5 
4-5 
3 ° 
123. 80 
— 7. 60 
0-14. 30 
4 A. 
5 
0-1 
38 
185. 70 
— 8. 20 
&-14. 30 
4 B . 
5 
4-5 
38 
114. 80 
&-14. 30 
&-14. 3a 
a A and B are different layers of same column. & Complete loss of NO 3 initially present. 
Here again the evidence shows that with a water content of 15 c. c. 
per 100 gm. of soil the nitrate accumulation increased with an increasing 
compactness and also with an increasing depth of column. With a 
moisture content of 20 c. c. per 100 gm. of soil the medium and compact 
samples both showed a greater nitrate gain than the loose. There was, 
however, slight difference between the two. Again, there is no evidence 
of lack of aeration in the lower-lying strata, the medium compact sample 
showing a much higher gain at the bottom than at the surface. 
At moisture contents of 30 and 38 c. c. per 100 gm. of soil, compacting 
inhibited nitrate accumulation in all except the surface of medium com¬ 
pact samples containing 30 c. c. of water. However, at both these moist¬ 
ure contents the compact samples were saturated. The medium sam¬ 
ples were saturated at 38 c. c. and approached very closely to saturation 
at 30 c. c. per 100 gm. of soil; hence, nitrification could not be expected 
to take place in them. At 30 c. c. of moisture per 100 gm. of soil the 
loose samples showed marked increases in the lower layers over the sur¬ 
face layers, while at 38 c. c., which is slightly above the optimum moisture 
content for this soil in loose condition, the surface soil showed the largest 
net gain. 
In the experiments reported in Table IV combinations of the three 
variable factors are presented. The calcium-carbonate content was the 
same as in previous experiments, while the nitrogen added was only 20 
mgm. per 100 gm. of soil. The samples were contained in 500-c. c. bottles 
and tall glass cylinders, and were incubated in a moisture chamber at 
room temperature for three weeks. In the samples marked “medium” 
the volume was reduced to three-fourths that of the “loose,” while the 
samples marked “compact” were reduced to one-half that of the “loose.” 
The ammonia was tested qualitatively in order to show whether or not 
nitrification was complete. 
