550 Journal of Agricultural Research voi. xxxi, no. 6 
Total nitrogen was determined by the Kjeldahl-Gunning method. 
Nitrates were determined by the phenoldisulphonic acid method, 
using the modification as recommended by the author (4) i* 1 case 
colored extracts. 
Soil reaction was determined by the Truog test (13). 
Ammonia was determined by the aeration method as recommended 
by Potter and Snyder (11), except that large test tubes IK b y. 14 
inches were used instead of Kjeldahl flasks to hold the soil suspension, 
and a cotton plug was inserted between the soil suspension and the 
absorption bottle to stop the spray formed during aeration. Fifty 
grams of soil and 100 c. c. of ammonia-free water containing 5 c. c. 
of a 40 per cent K 2 C0 3 solution were aerated for 8 hours at a rate of 
200 liters of air per hour. A little paraffin oil was used to prevent 
foaming. The amount of ammonia was measured by nesslenzation, 
except in case of the larger amounts which were determined by 
titration. . . _ ml 
The results of the first experiment are given in Table I. 1 here is 
evidently no correlation between the total nitrogen content of the 
soil and the ammonia content as Russell (12) suggested. Nor, 
evidently, is there any correlation between the ammonia content and 
the reaction of these soils. In practically every instance where a 
large amount of ammonia was present in the soil, the nitrate content 
was also Quite large* however, in some instances the nitrate content 
was quite large and the ammonia content quite small. 
Table I. — Ammonia, nitrate , total nitrogen content , and acidity of % soils varying 
widely in physical and chemical properties 
No. 
Soil type 
Source 
Acidity 
Total 
nitrogen 
per 
2,000,000 
pounds 
of soil 
Nitrogen 
as 
Ammonia 
nitrate 
Pounds 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
20 
21 
22 
23 
24 
Raw peat-- 
Decomposed peat- 
Clyde silty clay- 
Webster clay loam- 
Waukesha silt loam- 
Shelby loam..-- 
Tama silt loam-- 
Carrington silt loam.. 
Shelby loam.. 
Marshall silt loam. 
Carrington loam.. 
Baxter gravelly loam. 
Miami silt loam- 
Carrington loam.. 
Grundy silt loam- 
Shelby loam... 
Marion silt loam- 
Clarksville gravelly loam. 
Waverly silt loam- 
Buckner coarse sand- 
Marion silt loam.. 
Knox silt loam- 
Lintonia sand- 
Carrington sand.. 
Manistique, Mich. 
Madison, Wis- 
Racine County, Wis__ 
Ames, Iowa- 
La Crosse, Wis. 
Jamison, Iowa- 
State Center, Iowa.... 
Springville, Iowa- 
Udell, Iowa- 
Missouri Valley, Iowa_ 
Calamus, Iowa. 
Polk County, Iowa,... 
Rochester, Wis.. 
Independence, Iowa__ 
Mountain Pleasant, 
Iowa. 
Jamison, Iowa. 
Unionville, Iowa. 
Lawrence County, 
Very strong... 
Not acid_ 
_do—. 
_do.. 
Strong- 
Slight +_ 
Strong_ 
_do. 
_do.—- 
Medium.. 
Strong_ 
Slight. 
_do_ 
Strong.. 
Medium +— 
.do.- 
Very Strong- 
Slight +.- 
Mo. 
Polk County, Mo- 
Muscatine, Iowa.. 
Boone County, Mo... 
Missouri Valley, Iowa. 
Mississippi County, 
Mo. 
Vinton, Iowa. 
_do. 
Strong_ 
_do.- 
Not acid. 
Slight +- 
Medium +— 
43,800 
24,360 
9,260 
8,630 
6,550 
5,210 
4.280 
3,900 
3,380 
3.280 
3,280 
2,800 
2,740 
2,460 
2,460 
2,240 
1,990 
1,700 
1,580 
1,530 
1,510 
1,370 
700 
560 
P.p.m .« 
P. p. m. 
328.5 
32.8 
236.5 
23.2 
137.6 
7.5 
51.2 
6.7 
68)2 
3.4 
45.5 
7.8 
125.3 
8.2 
51.2 
3.9 
196.0 
60.7 
68.0 
29.9 
41.6 
3.7 
128.0 
18.7 
44.1 
3.5 
30.4 
2.6 
74.7 
7.9 
90.7 
6.0 
31.2 
7.2 
64.1 
46.6 
28.8 
16.6 
28.1 
4.5 
36.1 
9.6 
12.0 
9.1 
46.0 
11.2 
21.6 
3.9 
« P. p. m.=parts per million. 
