COCOA-GROWING COUNTRIES 441 



The chemical composition is remarkable for its very 

 high amount of potassium oxide (about 1 per cent) and 

 for the total absence of calcium carbonate (carbonate of 

 lime). Also the high percentage of iron is remarkable. 

 As regards the absence of carbonate of lime, attention 

 has often been drawn to this fact, and it has been 

 supposed that it may be the cause of various undesirable 

 facts, as, for instance, the extraordinary stiffness of the 

 soil, or the unsatisfactory growth of some crops, or the 

 presence of diseases in the cocoa. But the addition 

 of carbonate of lime or lime oxide has never had the 

 effect expected. For the cocoa tree such an addition 

 has always turned out to be quite useless. The cocoa 

 tree seems to find in the soil enough lime in another 

 form. 



However this may be, the soil is certainly very suit- 

 able for cocoa-growing. For years and years cocoa may 

 be cultivated on it without any manuring and without 

 showing any decline in yield. 



Moreover, manuring with chemical manures such as 

 basic slag, superphosphate, gypsum, guano, has always 

 had as little success as manuring with lime. 



The stiffness of the soil and its little porosity allows 

 the air to penetrate only to a rather low depth, and only 

 the surface, to a depth of 2 feet or '2Jr feet, is sufficiently 

 aerated to be suitable for the growth of the roots of the 

 cocoa tree. 



Thus the cocoa tree has developed into a " surface 

 feeder." The opinion expressed in so many handbooks 

 that the cocoa tree needs a deep soil to develop 

 its tap-root, is therefore not strictly correct. In 

 soils the cocoa tree grows successfully with only 

 superficially developed root system. In Surinam a 

 tap-root is only present in young trees. 



Another thing which can be seen in Surinam is 

 the remarkable amount of salt in the soil which a 

 cocoa tree can stand. 



Several small proprietors who have their grounds 

 near the river are only partially protected against the 



