AGRICULTURAL BULLETIN 
OF THE 
STRAITS 
AND 
FEDERATED MALAY STATES. 
No. 1.] JANUARY, 1909. [Vol. VIII. 
THE TREATMENT OF ACID SOILS FOR RUBBER 
AND OTHER CULTIVATIONS. 
A series of experiments have been begun by the Department of 
Agriculture on some low lying fiat land which has abnormally acid soil, 
rendering it unfavourable for the rapid growth of root growth of rub- 
ber or other cultivated plants. 
The presence of a too large proportion of acid in peaty soils is due 
to the existence of a large proportion of humic acid which is a brown 
or black substance produced by decaying vegetable matter. This de- 
composition is greatly facilitated by heat, air, and moisture and by the 
presence of putrefying nitrogenous matter. The conditions in many 
clearings in Malaya are therefore specially suited to the formation of 
an excess of humic acid which exists in many places to such an extent 
that the roots of young rubber are not able to grow and the plants 
grow without vigour and in some cases succumb. 
Such soils are physically and in other respects, most suitable for 
healthy and rapid growth of rubber and when the amount of acid has 
been reduced they often produce exceptionally fine rubber. 
The question of the neutralisation of such soils in the shortest 
time is of great importance. The only method used at present is to 
a low the sun free access to the soil and by tins means and plentiful 
drainage to gradually eliminate a proportion of the acid. 
This is however a lengthy and not always successful method and 
a much quicker plan is to add such proportion of basic substance such 
as lime as is needed to neutralize the acid in the soil. 
A very large supply of natural phosphate is being extracted from 
Lhnstmas Island and can be delivered comparatively cheaply at S. S. 
and F. M. S. ports. , 
This raw phosphate not converted into the superphosphate will 
be fried on acid soils. The advantage in using this manure is that the 
aiw phosphate i.e., phosphatic rocks exactly as they are obtained in 
