29 
The above table adds further proof toward indicating the small 
amounts of potash absorbed by this type of soil when added in mix- 
tures. (See also p. 25.) There is little decrease in concentration of 
the percolate with regard to this element. 
REMOVAL OF ABSORBED NITROGEN. 
In the following table will be found the results showing removal 
by distilled water of nitrogen absorbed from ammonium sulphate 
from soil No. 517: 
Removal of absorbed nitrogen. 
[Expressed in parts per million nitrogen in the percolate.] 
Percolates of 100 cc. each. 
Ammonium sulphate, potas- 
sium phosphate, and potas- 
sium sulphate. 
Ammonium sulphate, calcium 
phosphate, and potassium sul- 
phate. 
Untreated. 
Heated. 
Chloro- 
form. 
Untreated. 
Heated. 
Chloro- 
form. ■ 
200 
73 
51 
46 
42 
31 
25 
21 
16 
21 
21 
13 
68 
44 
39 
30 
20 
17 
16 
16 
16 
16 
16 
66 
44 
42 
33 
22 
22 
18 
16 
21 
18 
11 
84 
46 
28 
18 
7 
7 
4 
3 
11 
3 
2 
73 
38 
25 
13 
9 
7 
6 
5 
9 
4 
4 
73 
300 
40 
400 
22 
500 
10 
600 
700 .. 
3 
800 
3 
900 
3 
1,000 
6 
1,100 
2 
1,200 
2 
SUMMARY. 
Nitrogen fixed gm. . 
Nitrogen removed gm. . 
Per cent of nitrogen removed 
0.0342 
.0360 
0. 0152 
.0298 
0. 0350 
. 0313 
39.5 
0. 0268 
. 0213 
79.6 
0. 0194 
.0193 
99.4 
0. 0231 
.0164 
71.0 
The above table discloses the peculiar fact that practically all the 
nitrogen fixed by the soil from ammonium sulphate was removed by 
passing a liter of water through it. The concentration of the solu- 
tion tended to decrease toward a constant value, as was the case with 
all the other elements of plant food. 
SUMMARY. 
The data presented in the foregoing pages throw considerable 
light upon the behavior of fertilizer salts in Hawaiian soils. They 
show the variation in absorbing power with the variation in soil types 
and composition of fertilizer added. Hawaiian soils have resulted 
from the degradation of lava rocks, some of which have subsequently 
been changed through the addition of coral limestone or submergence 
by the sea. Therefore they would naturally be expected to be of a 
highly basic nature, and to yield a highly basic soil solution, depending 
upon the absorptive power of the soil. Some of the soils have been 
