THE AGRICULTURAL CHEMISTRY OF CACAO. 



93 



The unavoidable loss per acre in British Guiana as com- 

 pared with that in Venezuela given by Marcano, and with that 

 in Guadeloupe reported by Boname is as follows : 

 Bfc. FEU ACRE PER ANNUM. 



There is a general concordance in these results showing the 

 low amounts of constituents necessarily removed from the soil of 

 the production of a crop of cacao. 



Where the Erythrina is used as a shade tree, manuring 

 should be directed largely towards the upkeep of the potash and 

 phosphates necessary to enable the shade trees to do their parfc 

 as nitrogen collectors and where no shade trees are used the 

 mineral manuring ought to be more largely supplemented by 

 nitrogen. Thus the following mixtures or mixtures of other 

 materials yielding the same proportions of nitrogen, phosphates 

 and potash per acre might be advisedly tried on cacao 



plantations : 



Erythrina used for shade. Not shaded. 

 ' Nitrate of Soda ... ... i cwt. ... 2 cwt. 



Superphosphate of lime 36 % soluble f ,, ... 



Potash sulphate ... ... i ,, . 



The materials should be well mixed and applied in quantity 

 according to the number of trees planted per acre around each 

 tree at a distance of about two to three feet from the stem. 



An excellent way of applying pbosphatic manures to the 

 cacao tree is by the use of slag phosphate. This has given highly 

 satisfactory results, both in British Guiana and in Grenada. 

 "Where plantations are being newly started much advantage to 

 the growth of the plants may be obtained by mixing the soil in. 

 the immediate vicinity of where the cacao is to be planted with 

 from two to four Ibs. of slag phosphate meal. 



Attention has also been directed to ascertaining the changes 

 which the beans with the surrounding pulp undergo during the 

 operations of fermenting and curing. For this purpose cured beans 

 were analysed of the two varieties from the same plantation 



* Average return per acre assumed to be 450 Jbs. 



