57 



When howeyer we take into consideration the higher proportion of 

 husk in the fruit of Forastero, we find that this yariety returns more 

 nitrogen, more phosphoric anhydride and but little less potash to the 

 soil in the waste husks than does an equal weight of the fruit of Cala- 

 bacillo. But it requires double the weight of fruit of Forastero than of 

 Calabacillo to produce an equal weight of cured cocoa, hence the return 

 to the soil by the husks is more than twice as great in the case of the 

 former than of the latter. 



Assuming that the average yield here of the variety Calabacillo, is 

 250 lbs. and that of Forastero 150 lbs. of cured cocoa per acre respec- 

 tively, we find that the amounts of the constituents of plant food re- 

 moved from the land annually in the whole fruit, returned to the soil 

 in the husks and either sold in the cured cocoa or lost in the sweatings 

 from the fermenting boxes, are as follows : — 



Pounds per acre per annum. 



Variety of Cocoa. 



Calabacillo. 



Forastero. 



Parts of fruit referred to. 



Whole 



Refuse 



Beans 



Whole 



Refuse 



Beans 



fruit. 



husk. 



and pulp. 



fruit. 



husk. 



and pulp. 



Weight per acre. 



6,200 



6,000 



1,200 



6,900 



6,200 



700 



Nitrogen 



20-15 



8 85 



11-30 



19 04 



11-78 



7-26 



Phosphoric anhydride ... 



9-42 



4-10 



5-32 



10 14 



5 95 



4-19 



Potash 



29-01 



22-70 



6-31 



25-39 



22 19 



3-20 



Lime 



2-60 



1-95 



65 



2-76 



2-29 



•47 



Magnesia 



7-44 



4-75 



2-69 



8-21 



6-26 



1-95 



The unavoidable loss per acre in this colony as compared with that 

 in Venezuela given by Marcano, and with that in Guadeloupe reported 

 by Boname is as follows : — 



lbs. per acre per annum. 

 Demerara. Venezuela. Guadeloupe .* 



Calabacillo Forastero Varieties not stated. 



Nitrogen ... 11-30 7-26 8 7 7-3 



Phosphoric anhydride... 6 32 4*19 4-5 2-8 



Potash ... 6-31 3-20 3-7 4-3 



Lime ... -65 -47 1-4 -4 



Magnesia ... 2 69 1-95 1- 1 4 



There is a general concordance in these results showing the low 

 amounts of constituents necessarily removed from the soil by the pro- 

 duction of a crop of cocoa. 



In the absence of direct experiments on the manuring of cocoa we 

 have formed our opinion that where the Erythrinse are used as shade 

 trees, manuring should be directed largely towards the upkeep of the 

 potash and phosphates necessary to enable the shade tress to do their 

 part as nitrogen collectors and that 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 



* Average r«turn per acre assumed by us to be 450 lbs. 



