147
RESULTS OF THE EXAMINATION OF SOIL FROM HỌNG KONG.
Imperial Institute No. M. 3283.
Date: 31st May, 1929.
Reference: A. Top-soil; So Kwun Wat; Cultivated; first class padi crops recently grown
on area.
Description: Greyish 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 Magnesia
...Cao
0.08
0.037
1048
0.046
..MgO
0.02
0.022
623
0.009
Potash
KO
0.04
0.006
170
0.010
Soda
...Na 20
0.03
0.009
255
0.008
Ferric oxide
.Fe 20
0.79
0.128
Alumina
..AL2O
0.009
4.37
2 3
-0.058 ·
Phosphoric acid Silica
PO
0.01
0.005
142
2
SiO 2
Total
per cent.
lb. per acre.
...N
0.071
0.777
2011 22011
1.41
Nitrogen
Organic carbon ...C
Organic matter
.*
Carbon dioxide ...CO2
*Obtained by multiplying the figure for organic carbon by
100
55.
The figures for lb. per acre of the various constituents in the above table are calculat- ed 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
12.8
Composition of clay fraction (0.002 mm. and under, separated by sedimentation).
per cent.
Silica
Alumina
Ferric oxide
...Sio. ...Al2O.
2
43.90 34.41
3
.Fe2O
3.23
3
Titanium dioxide
..Tio.
0.25
Manganous oxide
... Mno
0.01
Lime
CaO
nil.
Magnesia
...MgO
0.39
Potash
...K,O
0.70
Soda
Na2O
0.30
Loss on ignition
17.00
Phosphoric acid
...P2O3
0.19
Total
100.38
Molecular ratio
{
Silica.
SiO2
=2.17.
Alumina, Al2O,
3