THE NITROGEN OF HAWAIIAN SOILS. 
The soils used in this investigation belong to the latcrite class com- 
mon to the islands. Sample No. 379 is a silty loam, containing con- 
siderable amounts of organic matter. It was taken from old pasture 
land in the Kula district of Maui, where semiarid conditions prevail. 
Sample Xo. 428 is a highly organic sandy soil from Glenwood, in 
the Hilo district of Hawaii, where the rainfall is very heavy, but good 
drainage prevails. The sample came from land recently cleared of a 
tropical jungle and may be considered virgin fern forest soil. 
Sample No. 447 is a silty loam from the Kunia district of Oahu, 
where semiarid conditions prevail, and is now being used for pine- 
apples, but formerly was devoted to pasture for many years. 
Sample Xo. 292 taken from the lands previously used for rice experi- 
ments by this station, represents a loam soil containing considerable 
gravel, and has been devoted to aquatic agriculture for many years. 
Samples Xos. 343 and 345 are each rice soils of a silty character, 
having been taken from the Kaneohe district on the windward side of 
Oahu. These lands have been devoted to continuous rice culture for 
from 30 to 40 years. 
Sample No. 347 is a highly humus soil, taken from the Punuluu dis- 
trict of Oahu, and likewise has been continuously cultivated in rice 
for thirty or more years. 
Samples Nos. 405 and 406 are silty soils taken from the Kalihi dis- 
trict of Oahu, and have been devoted to aquatic agriculture for many 
years, the former to rice and the latter to taro. 
NITRATE AND AMMONIA. 
It was deemed of interest to determine the amounts of nitrate and 
ammonia present in the soil prehminary to a study of the organic 
constituents. Nitrate was determined from water solutions, by the 
use of the phenol-disulphonic acid method, while the ammonia was 
determined by the direct distillation of separate portions of the soil 
with magnesium oxid. The results calculated to the water-free basis 
are given in the following table: 
Total nitrate and ammonia nitrogen in Hawaiian soils. 
Total 
nitrogen, 
per cent. 
Xitrate nitrogen. 
Ammonia nitrogen. 
Soil No. 
Parts per 
million. 
Per cent 
of total 
nitrogen. 
Parts per 
million. 
Per cent 
of total 
nitrogen. 
379 
0.592 
.770 
. 354 
.122 
.220 
1.241 
. r '. 
. 10 
4.5 
4 


70 
1 
15 
0. 109 
. 58 1 
1.751 
.328 
.000 
.000 
.050 
.329 
10 
220 
10 
10 
22 
32 
130 
50 
GO 
0.169 
428 
2. <>1 
447 
292 
343 
1.000 
34") 
1.468 
347 
1.048 
40') 
406 
]. 310 
