176 COCOA 



CHAP. 



of cocoa if they were more easily to be obtained in 

 large quantities. 



In one case, however, this kind of manure is in- 

 dispensable, viz. when cocoa is grown without shade 

 trees. In Grenada, where this manner of cocoa-growing 

 is general, every plantation has a good number of cattle 

 to supply the amount of manure necessary for the soil. 

 This fact shows clearly that the most important function 

 of the shade trees is to provide new humus by its fallen 

 leaves, and to preserve the humus by shading the soil. 



The regular application of farmyard manure or 

 compost is, so far as can be ascertained, not carried out 

 in any other cocoa-growing country except Java. But 

 that it would have excellent results in other countries 

 is shown by several fertilising experiments. 



In Dominica such experiments were started in 1902. 1( 

 Plots were treated with artificial manure alone (basic 

 slag and sulphate of potash) ; with these mixed with 

 dried blood ; and with mulchings of leaves and grass. 

 The result was that the greatest increase in yield took 

 place on the mulched plot, the average increase during 

 eight years being nofc less than 616 Ibs. per acre per 

 year. The manuring with basic slag, sulphate of potash 

 and dried blood also gave good increases, but not as 

 big as the mulching, the expense of which was much 

 smaller than in the case of any of the others. It 

 should be pointed out, however, that the effect of the 

 mulching is not so quickly seen as those of the chemical 

 manures and the dried blood, but it increases gradually. 

 The superiority of the mulching is, therefore, especially 

 apparent in the fourth and following years. 



The following figures give an outline of the results 

 of the experiments : 



1 " Results of the Recent Experiments with Cacao in the West Indies " ( West 

 Indian Bulletin, vol. ix. pp. 138-148) ; Report on the Botanic Station, etc., 

 Dominica, 1909-1910, p. 24. 



[TABLE 



