ii4 RUBBER AND 



through cacao, but this practice is objectionable owing 

 to the identity of several diseases to which the two 

 crops are subject, notably canker. Cotton has been 

 suggested, but the climates required by the two crops 

 are widely different, since a prolonged dry season is 

 necessary for the successful harvesting of the fibre. In 

 Sumatra and Java coffee is frequently grown in con- 

 junction with the early stages of rubber, and many other 

 crops have been suggested. Amongst these, Indigo is 

 one which seems to deserve more attention than it has 

 hitherto received. Indigo is an efficient gatherer of 

 nitrogen, and in the case of this crop practically the 

 whole of the materials removed from the soil, together 

 with the additional nitrogen, can be returned in the 

 so-called sect in a readily available form. Indigo 

 cultivation however requires special knowledge and 

 appliances, and these it might not be worth while to 

 introduce, owing to the comparative shortness of the 

 period available before the shade of the rubber prevents 

 the further growth of such a crop. 



Schidrowitz and others consider that no intercrop 

 has yet been proposed which will give a return greater 

 than the relative loss occasioned by the slower growth 

 of the rubber, so long as the price of rubber remains 

 high. The question is not however finally settled, and 

 much depends upon whether it is decided to plant the 

 rubber trees at the distance at which they will finally 

 stand, or to adopt close planting and subsequent thinning 

 of the plantation. 



