50 
Journal of Agricultural Research 
Vol. VTI, No. a 
humid soils. A minor objection which has been urged may also be 
mentioned here—namely, that of a given lot of soil collected at the same 
time two ioo-gm. samples may give widely different nitrifying powers. 
It may be observed here that the writers have never been able to sub¬ 
stantiate such a claim. They have merely called attention to some of the 
most important and perhaps the only important objections in the path 
of validating such comparative studies and other similar ones. It will 
be noted that scarcely any comment has been made regarding the objec¬ 
tions and difficulties in question. Occasion will be taken to examine 
them critically and evaluate their importance in a more proper place. 
It may be said that in these experiments the attempt has been made to 
obtain relative and not absolute values, and despite the accompanying 
weaknesses of the methods, it is believed that current ideas with respect 
to the intensity of nitrification in the soils of humid and of arid regions 
have been improved and rendered more definite. 
EXPERIMENTS WITH “FOREIGN ” 1 SOILS 
The word “foreign” is applied in this paper to soils coming from other 
States than California, unless specifically qualified in some other manner. 
While subsoils were available in every case and were studied in the 
foreign soils and while several soil types were available from some 
States, only one such type of surface soil and the results obtained there¬ 
with will be discussed. The results obtained with the foreign soils, 
arranged as above described, follow in Table I, which gives the results 
of nitrification of the soil, sulphate of ammonia, dried blood, and cotton¬ 
seed-meal nitrogen. 
Table; I. — Comparison of the nitrification in soils from various States a 
State. 
Soil type. 
Soil nitrogen 
(Group I). 
Soil nitrogen 
and sulphate 
of ammonia 
(Group II). 
Soil nitrogen and 
dried blood 
(Group III). 
Soil nitrogen 
and cotton¬ 
seed meal. 
(Group IV). 
Nitrate nitro¬ 
gen produced. 
Total soil ni¬ 
trogen present. 
Nitrogen in 
soil nitrified. 
Nitrate pro¬ 
duced. 
Total nitrogen 
present. 
Nitrogen nitri¬ 
fied. 
Nitrate pro¬ 
duced. 
Total nitrogen 
present. 
Nitrogen nitri¬ 
fied. 
Nitrate pro¬ 
duced. 
Total nitrogen 
present. 
Nitrogen nitri¬ 
fied. 
Per 
Per 
Per 
Per 
Mg. 
Mgm. 
ct. 
Mg. 
Mgm. 
ct. 
Mg. 
Mgm. 
cent. 
Mg. 
Mgm. 
ct. 
Alabama. 
Norfolk sandy 
9.20 
23.60 
38+ 
1.50 
63.60 
2+ 
0.10 
155-60 
Tr. 
4.10 
73 -60 
5 + 
loam. 
Alaska. 
Rich peat. 
225.20 
1.10 
265. 20 
Tr. 
81.10 
357- 20 
22+ 
2 <. IO 
272.20 
9 + 
Arizona. 
Fine sandy loam 
46.00 
86.00 
178.00 
93 -oo 
(Alkali). 
Arkansas. 
Huntington clay 
r3-8o 
68.40 
20+ 
5-40 
108.40 
4 + 
7.80 
200.40 
3 + 
13-30 
115-40 
11 + 
loam. 
Colorado. 
Silt loam. 
7. 5 ° 
108.30 
6+ 
I 7 - 5 ° 
148.30 
11+ 
29 * 50 
12 + 
IQ. CO 
Tee. 40 
12 “f" 
Connecticut.... 
Gloucester fine 
5 - 60 
209.80 
2+ 
7.00 
249.80 
2+ 
9.00 
341-80 
2 + 
18.00 
256. 80 
7+ 
sandy loam. 
Delaware. 
Sassafras loam ... 
54 - 75 
109.00 
50+ 
34 - 75 
149.00 
23 + 
66.75 
241.00 
27+ 
54 - 75 
156. OO 
35+ 
Florida. 
Calcareous peat 
54 -oo 
1894.00 
3 + 
32. 00 
193400 
1 + 
52.00 
2026.00 
2+ 
42.00 
194I.OO 
2+ 
(Everglades). 
1 This term was borrowed from Sackett (io). 
a Does not include Hawaii, Porto Rico, or California. 
