JAMAICA. 



BULLETIN 



OF THE 



BOTANICAL DEPARTMENT. 



Nt^ Series.] MABCH, 1898. - 



Part 3. 



THE AGRICULTURAL CHEMISTRY OF COCOA. 



Extract from Report on the Agricultural Work in the Botanic Grardens 

 of British Guiana for the years 1893-4-5. By Gr. S. Jexman, Govt. 

 Botanist, and J. B. Harrison, Govt. Analyst. 



Our attention has been directed to the little that is known, or at any 

 rate published in a readily available form, about the agricultural re- 

 quirements of this important crop. We have, therefore, devoted some 

 time to the study of the chemical constituents and requirements of the 

 Cocoa, and to that of the changes in composition which take place daring 

 the fermentation and curing of the beans. 



The composition of the different parts of the cocoa tree has been 

 treated upon by Marcano of Venezuela (a), and in part by Bona me, late 

 of Guadeloupe, now of Mauritius (b). Our opportunities for studying 

 the requirements of the plant as represented by the composition of the 

 mature trees themselves being very limited, we prefer to accept for our 

 guidance in this colony the results given by Marcano. This authority 

 estimates that a cocoa tree twenty years old is made up of — 



Trunk ... ... ... 49*5 



Large branches ... ... ... 21-1 



Medium branches ... ... 



Small shoots ... ... 12* 



Leaves ... ... ... 6*4 



100*0 



and that a plantation of trees of this age growing on one acre will con- 

 tain— 



Nitrogen ... ... 201 lbs. 



Phosphoric anhydride ... 95 " 



Potash ... 251 « 



Lime "... 400 " 



Magnesia ... ... Ill 



(a) Essais d'Agronomie Tropicale. Y. Marcano. 



ip) La culture de la canne a sucre a la Guadeloupe, Ph. Boname. 



