68 
Journal of Agricultural Research 
Vol. VII, No. a 
it is clear that the Ukiah area should stand first among the California 
series here studied. This is so because it receives more rain in a longer 
rainy season and is not subjected to the extremely high tenperatures 
and other conditions favorable to loss of nitrogen which exist in the 
more arid areas. There are only three soils in the Ukiah area, or about 
io per cent of the whole number, which contain less than 0.05 per cent 
of total nitrogen. Two of these approach that point rather closely and 
the other contains nearly 0.03 per cent of nitrogen and is the only soil 
which is seriously deficient in nitrogen in the whole area. The 10 per 
cent value just given, when compared with corresponding values for 
other California areas, again supports the relationship drawn above 
between climate and soil nitrogen content and which for the first time is 
being properly emphasized. 
Table) VI .—Nitrification in Ukiah area soil types 
Name of type. 
Soil nitrogen 
(Group I). 
Soil nitrogen and 
sulphate of ammo¬ 
nia (Group II). 
Soil nitrogen 
and dried blood 
(Group III). 
Soil nitrogen 
and cottonseed 
meal (Group IV). 
Ni¬ 
trate 
pro¬ 
duced 
Total 
ni¬ 
trate 
pres¬ 
ent in 
soil. 
Ni¬ 
tro¬ 
gen 
nitri¬ 
fied. 
Ni¬ 
trate 
pro¬ 
duced 
Total 
nitro¬ 
gen 
pres¬ 
ent in 
soil. 
Ni¬ 
tro¬ 
gen 
nitri¬ 
fied. 
Ni¬ 
trate 
pro¬ 
duced 
Total 
nitro¬ 
gen 
pres¬ 
ent in 
soil. 
Ni¬ 
tro¬ 
gen 
nitri¬ 
fied. 
Ni¬ 
trate 
pro¬ 
duced 
Total 
ni¬ 
trate 
pres¬ 
ent in 
soil. 
Ni¬ 
tro¬ 
gen 
nitri¬ 
fied. 
Ukiah gravelly loam. 
Vichy fine sandy loam. 
Russian silt loam... 
Pinole gravelly loam... 
Finn gravelly loam. 
Qrr loam. 
Large gravelly loam. 
Russian silty clay loam. 
Russian silt loam. 
Largo silty clay.... 
Largo loam. 
Sanelloam. 
Guidiville sandy loam. 
Tehama loam. 
Russian fine sandy loam... 
Diablo day. 
Finn loam..... 
Dublin clay. 
Russian loam...,,. 
Largo silt loam. 
Mendocino loam. 
Tehama gravelly loam. 
Finn gravelly day loam.... 
Pinole loam. 
Diablo loam. 
Orr clay loam. 
Pinole sandy loam. 
Mendocino gravelly loam... 
Mgm. 
0.10 
.02 
1.42 
2.94 
•30 
4-79 
2*47 
S* 5 ° 
2.08 
3*63 
6.10 
.48 
3*59 
•03 
•8s 
2*39 
1.42 
3*52 
6*45 
7.00 
2.69 
1.00 
1.24 
3*oo 
3 * 3 ° 
5 *io 
2. 72 
5*46 
Mgm. 
156.80 
29.40 
91.00 
77.00 
70.00 
75 * 60 
203.00 
147*00 
140.00 
152.60 
163.80 
58.80 
42.00 
49.00 
53*20 
63.00 
61.60 
147.00 
120.40 
135 * 80 
61.60 
67. 20 
75.60 
54 * 60 
85.40 
112.00 
85.40 
95* 20 
P.ct. 
Tr. 
Tr. 
i+ 
3 + 
Tr. 
6+ 
i+ 
3+ 
1+ 
2+ 
_ 3 + 
Tr. 
8+ 
Tr. 
1+ 
3 t 
2+ 
2+ 
5 + 
5 + 
4 + 
1+ 
1+ 
5 + 
3 + 
4 + 
3 + 
5 + 
Mgm. 
—0.40 
— .28 
2.42 
3*64 
.44 
15*79 
4*37 
7 * 50 
5 * 58 
6*93 
12.00 
.28 
8.39 
— . 12 
8*35 
13.89 
1.32 
5*82 
10.95 
10.80 
3*99 
1.20 
.28 
2.40 
2.90 
13 * 70 
5.62 
15*66 
\Mgm. 
196.80 
69.40 
131*00 
117.00 
no. 60 
115.60 
243*00 
187.00 
180.00 
192.60 
203.80 
98.80 
82.00 
89.00 
93*20 
103.00 
101.60 
187.00 
160.40 
I 75 * 8 o 
ioz.60 
107. 20 
115.60 
94 * 60 
125.40 
152.00 
125.40 
135. 20 
P.ct. 
'1+ 
3 + 
Tr. 
^ 3 + 
1+ 
4 + 
3 + 
3 + 
^5 + 
Tr. 
10+ 
8+ 
13 + 
1 + 
3 + 
6+ 
6+ 
3 + 
1+ 
Tr. 
2+ 
2+ 
9 + 
4 + 
1 + 
Mgm. 
0.60 
. 12 
1.82 
— .06 
1.90 
6.29 
18.97 
28.50 
29.58 
20.93 
23.60 
— .02 
— ,41 
.98 
8-35 
11.89 
— .08 
23.92 
— .05 
4*30 
— .01 
6.60 
1.64 
. 02 
39 * 70 
— .08 
26.66 
Mgm. 
288.80 
161.40 
223.00 
209.00 
202.00 
207.60 
335 -oo 
279.00 
272.00 
284.60 
295.80 
190.80 
174. 00 
181.00 
185. 20 
i95*oo 
193* 60 
279.00 
252.40 
267.80 
193*60 
199. 20 
207.60 
186.60 
217.40 
244.00 
217.40 
227. 20 
P.ct. 
Tr. 
Tr. 
Tr. 
Tr. 
3 + 
5 + 
10+ 
10+ 
7 + 
7 + 
Tr. 
4 + 
6+ 
8+ 
1+ 
^ 3 + 
Tr. 
16+ 
11+ 
Mgm. 
0.50 
•52 
1.82 
3*54 
. 20 
2.19 
8.77 
12.00 
8. 58 
9*53 
13*60 
■07 
14. 79 
*36 
8 - 3 S 
21.49 
■ 72 
10.32 
5-15 
4.00 
.01 
*32 
1.04 
.68 
2.58 
19. 70 
9.02 
11.86 
Mgm. 
203.80 
76.40 
138.00 
124.00 
117.00 
122.60 
250.00 
194.00 
187.00 
199.60 
210.80 
105.80 
89-00 
96.00 
100.20 
no. 00 
108.60 
194.00 
167.40 
182.8b 
108.60 
114. 20 
122.60 
101.60 
132.40 
159-00 
132.40 
142.20 
P. ct. 
Tr. 
Tr. 
1+ 
2+ 
Tr. 
1+ 
3 + 
6+ 
4 + 
4 + 
6+ 
16+ 
Tr. 
8+ 
x 4 + 
Tr. 
5 + 
3 + 
2+ 
Tr. 
Tr. 
Tr. 
1+ 
12+ 
6+ 
8+ 
With reference to the absolute amounts of nitrate produced from soil 
nitrogen, it will be seen that the Ukiah soils are distinctly superior to 
the Bay area soils. Thus, 6 soils in the Ukiah area produce more than 
5 mgm. of nitrate nitrogen, as against only 1 in even a larger total number 
of soils in the Bay series. Moreover, 1 of the 6 soils under discussion 
reaches a nitrate production equivalent to 7 mgm. Two soils in the 
