175
RESULTS OF THE EXAMINATION OF SOIL FROM HONG KONG.
Imperial Institute No. M. 3283.
Date: 31st May, 1929.
Reference: H. Top-soil: Tai Pak; Lantao: Uncultivated; pine and wild trees, ferns and
grass growing on area.
Description: Yellowish-grey sandy loam.
RESULTS OF EXAMINATION.
Chemical analysis of "Fine earth" passing a 1 mm. sieve.-
Soluble in hydrochloric acid
Available constituents i.e., portion soluble in 1%
citric acid solution.....
Exchangeable bases (Hissink method)
per cent.
per cent.
lb.
per acre.
per cent.
Lime
...Cao
0.07
0.014
376
-0.018
Magnesia
...MgO
0.04
0.008
220
0.014
Potash
...K2O
0
0.09
0.005
138
0.010
Soda ...
...Na,O
0.13
-0.010
276
0.014
Ferric oxide
...Fe,03
1.19
0.047
trace
Alumina
A1,0,
7.32
0.122
3
0.028
Phosphoric acid P20
trace
trace
5
Silica
...Sio
2
Nitrogen
Total:
per cent.
lb.
per acre.
...N
0.062
1708
0.712
19618
1.29
.CO. 2
Organic carbon ...C
Organic matter*
Carbon dioxide
100
*Obtained by multiplying the figure for organic carbon by.
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.
C
Atomic ratio Carbon, 13.5.
Nitrogen, N
Composition of clay fraction (0.002 mm. and under, separated by sedimentation).
per cent.
Silica Alumina
...SiO 2
41.71
..A1,03
35.18
Ferric oxide
.Fe2O
4.46
Titanium dioxide
...Tio,
0.22
Manganous oxide
...MnO
trace
Lime
...Cao
0.13
Magnesia
...MgO
0.58
Potash
..K2O
0.78
2
Soda
...Na2O
0.38
Loss on ignition
16.26
Phosphoric acid
..P20,
0.08
Total
99.78
Silica,
SiO 2
Molecular ratio
=2.02.
Alumina, Al,03
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