ABSORPTION OF FERTILIZER SALTS BY HAWAIIAN 
SOILS. 
In undertaking investigations on soil fertility it is very necessary 
to have some knowledge of the absorptive or fixing power of a soil, 
since this factor is one of prime importance in the successful use of 
fertilizers and varies greatly with the physical structure, the organic 
matter content, and other factors of a chemical and biological nature. 
OBJECT OF WORK. 
The object of the work here presented was to give some under- 
standing of the absorptive power of Hawaiian soils for fertilizer salts. 
These soils contain an abnormally high percentage of iron and alu- 
minum compounds, and from their physical condition would be 
expected to have a high fixing power. Many of the soil types of the 
islands also contain large amounts of organic matter and humus. 
J. T. Crawley x carried on some experiments with Hawaiian soils to 
determine the effect of irrigation upon added fertilizer salts. He 
found phosphoric acid to be firmly fixed, while ammonium sulphate 
and potassium sulphate were not so strongly fixed. 
SOIL TYPES USED. 
Soils representing in a general way the important types of the 
islands were selected for the work. The following table shows the 
chemical composition of the soils, as determined by digestion in 
hydrochloric acid of specific gravity 1.115: 
Composition of soils used in the experiments. 
Constituents. 
Moisture 
Volatile matter 
Insoluble matter 
Ferric oxid (Fe 2 3 ; 
Alumina (A1 2 3 ) 
Titanium oxid (Ti0 2 ). . . . 
Manganese oxid (Mn 3 4 ;. 
Lime(CaO) 
Magnesia (MgO) 
Potash (K 2 0) 
Soda(Na 2 0) 
Sulphur trioxid (SO a ). .. . 
Phosphoric acid (P^ >») - - 
Soil No. Soil No. 
292. 448. 
Per cent. 
7.65 
8.42 
38.49 
16.63 
12.85 
2.00 
.24 
1.84 
8.71 
.39 
1.36 
.08 
.57 
Per cent. 
15.00 
25.58 
15.10 
19.20 
16.64 
4.20 
.06 
.50 
1.80 
.15 
.68 
.53 
.29 
Soil No. 
428. 
Per cent. 
14.95 
22.24 
34.99 
8.24 
10.73 
3.20 
.20 
1.91 
2.24 
.24 
1.40 
.45 
.22 
Soil No. 
474. 
Per cent. 
13.59 
20.01 
33. 77 
7.00 
1G.79 
1.80 
.07 
3.80 
.85 
.72 
.10 
.45 
2.18 
Soil No. 
517. 
Per cent. 
3.54 
13.71 
41.99 
21.76 
17.23 
i Jour. Amer. Chem. Soc., 24 (1902), p. 1114; 25 (1903), p. 47. 
(5) 
Soil No. 
518. 
Per cent. 
3.97 
13.56 
41.53 
21.46 
18.21 
.12 
.36 
.32 
.54 
.23 
.58 
.13 
.04 
.20 
.24 
.66 
.46 
.52 
.16 
