Oct. 8, 1917 
Nitrate-Nitrogen Accumulation in Soil 
45 
Table I .—Variations in the nitrates and ammonia produced in Oswego silt loam under 
different conditions of incubation —Continued 
Sample 
No. 
Container. 
Quantity 
of soil. 
Nitrogen 
asN 03 . 
Ammonia 
(NH 3 ). 
-26. 
Targe petri dish, open. 
Gm. 
IOO 
Mgm. 
54 - 2 
54 . 2 
52. 8 
58. O 
55 *o 
57-2 
58. 0 
59- 8 
58. 0 
55 - 0 
52. 8 
49.0 
37-4 
26. 4 
7.0 
~ * 9 
Trace. 
Slight. 
Trace. 
. 
■27 . 
.do. 
0 IOO 
O 1 . 
38A. 
•?8B 
20-inch cylinder, cotton-plugged. 
a 900 
a 900 
a 900 
Do. 
.do. 
Do. 
* * * * 1 
?8C . 
,.:.:do. 
Do. 
• * * * 1 
28D. 
.do. 
a 900 
a 900 
a 900 
a 900 
a 900 
a 1, 400 
a 1, 400 
a i, 400 
a I? 400 
a I? 400 
a I? 400. 
a x 5 400 
a 1, 400 
IOO 
Do. 
?8E. . ■. 
.do. 
Do. 
?8F. 
.do. 
Do. 
. 
^ 8G. 
.do. 
Do. 
• * * ■ 
38H.... 
.do. 
Do. 
goA .... 
.do.... 
Some. 
oy Ai • * 
30B.... 
.do. 
Do. 
7 nC . . . 
.do. 
Do. 
oy~ • ■: 
-2 qD. 
.do. 
Abundant. 
^qE .... 
.do... 
Do. 
-2qF. 
1.do. 
Do. 
30G. . . . 
.do. 
Do. 
.do. 
00. 0 
Do. 
.. 
07 " 
AO . 
500-c. c. bottle, sealed. 
55 -o 
5 S-o 
58.3 
Trace. 
*t w * * * " 
AI. 
Large Fembach flask. 
IOO 
Do. 
A 2 . 
. 
.do. 
I, 000 
Do. 
a Packed. & Samples below this depth were not analyzed. 
The data recorded in Table I support the following observations: 
(а) The quantity of soil varied from 50 to 1,000 gm., with but little, 
if any, effect upon nitrate accumulation. Apparently there were slightly 
larger quantities of nitrate nitrogen in the large volumes of soil and also 
slight quantities of ammonia nitrogen in the smaller volumes. However, 
the differences in both instances are probably within the limit of error. 
There is no evidence that increasing the volume of soil decreases nitrate 
formation. 
(б) The depth of the column of soil varied from % inch (No. 42) to 20 
inches (No. 39) without producing any appreciable effect upon nitrate 
accumulation, provided the soil was left loose. There is also no evidence 
that nitrate formation 20 inches below the surface was any less vigorous 
than at the surface, provided the soil was left unpacked. 
(c) Packing the soil in a thin layer (No. 38) was without effect/ If, 
however, the depth of the column was appreciably increased, packing 
(reducing volume from 14 to 9) decreased very markedly the nitrate 
accumulation (No. 40), the accumulation becoming negative only a few 
inches below the surface. In view of the data to follow, it should be 
borne in mind that, with a water content of 27 c. c. per 100 gm. of soil, 
reducing the volume of this soil from 14 to 9 increased the percentage 
saturation from one-half to practically complete saturation. 
( d ) Decreasing the ratio of surface exposed per 100 gm. of soil from 
314 square centimeters (No. 42) to 2 square centimeters (No. 39) was 
without effect upon the nitrate accumulation. 
