171
RESULTS OF THE EXAMINATION OF SOIL FROM HONG KONG.
Imperial Institute No. M. 3283.
Date: 31st May, 1929.
Reference: G. Top-soil; Shek Kwu Lung; Uncultivated; pine and wild trees, ferns and
grass growing on area.
Description Yellowish-brown loam.
RESULTS OF EXAMINATION.
Chemical analysis of "Fine earth" passing a 1 mm. sieve.
Available constituents i.e., portion soluble in 1%
citric acid solution
Soluble in hydrochloric acid
Exchangeable bases (Hissink method)
per cent.
per cent. lb. per acre.
per cent.
Lime Magnesia
Potash
...Cao
..MgO ...K2O
0.10
0.008
174
0.012
0.36
0.015
326
0.019
0.20
0.008
174
0.007
2
Soda
...Na.O
0.16
0:008
174
0.009
Ferric oxide
Alumina
Phosphoric acid Silica
...Fe2O3 A1,03 P2O ..SiO.
2 5
2
2
5.75
0.067
trace
11.58
0.208
0.032
· 0.03
slight trace
Total
per cent..
Ib.
per acre.
Nitrogen
...N
0.183
3971
Organic carbon ...C
1.79
38843
Organic matter*
3.26
Carbon dioxide ...CO,
*Obtained by multiplying the figure for organic carbon by
100
The figures for lb. per acre of the various constituents in the above table are calculated for a depth of 9 inches of soil, the apparent specific gravity of the soil being taken into consideration.
Atomic ratio{
Carbon, C Nitrogen, N
11.4.
Composition of clay fraction (0.002 mm. and under, separated by sedimentation).
per cent.
Silica Alumina
...SiO 2
34.70
.....ALO 3
31.60
Ferric oxide
...Fe20
12.63
Titanium dioxide
...Tio,
0.87
2
Manganous oxide
...MnO
0.09
Lime
...Cao
0.12
Magnesia
MgO
0.59
Potash
...K.O
0.96
Soda
...Nã2O
0.12
2
Loss on ignition .......
17.89
Phosphoric acid
...P2O
0.54
2
Total
100.11
Silica.
Molecular ratio
SiO2 Alumina, Al,03
- 1.86.