THE FERTILITY OF SOILS IN THE TROPICS 4! I 



notes will serve for comparison with those forthcoming 

 from other tropical countries in which perhaps knowledge 

 of the subject is in a state more advanced. 1 



It has not been possible as yet to undertake any bac- 

 teriological work, but it is hoped to do so later, as the 

 solution of many problems of interest may be expected 

 from this mode of attack. 



To prevent confusion, it will be convenient to keep 

 separate the remarks on the composition of the rubber 

 and coconut soils respectively, but as regards the 

 methods of improvement that may be employed, these 

 are of a general nature and apply equally to both; they, 

 therefore, will be dealt with at the end. 



RUBBER SOILS. 



Mechanical Composition. The soils on which rubber 

 is planted in the Federated Malay States may be divided 

 into three classes : those composing the undulating land, 

 rising up to 500 ft., that broadens down from the central 

 range of granitic mountains; the flat land forming the 

 plains and valleys and formed alluvially from the former; 

 and the fiat, peaty, coast soils, probably fairly recently 

 laid down by the sea, and, at the time of reclamation, 

 consisting of tidal mangrove swamp. 



Of these the first and the last have produced the 

 highest yielding estates : the first because, owing to the 

 light sandy nature and perfect natural drainage, deep 

 and extensive rooting has been possible; the last when 

 artificially well drained only, and when sufficient organic 

 matter is present to have the same effect as sand in 

 rendering the soil light and porous. Where both these 

 conditions are not fulfilled the land is far from being 

 satisfactory and is in some cases proving a source of 

 great anxiety to the planter. 



The second class mentioned, the inland alluvial soils, 

 is less suitable, not on account of any deficiency in plant 

 food material, but because of its close and impermeable 

 texture. It contains little organic matter, and large pro- 



1 The methods of analysis adopted are those recommended by 

 Hall and Russell. 



