THE CULTIVATION OF COCOA 171 



composition of the crop is, in this respect, of still less 

 use than chemical analysis of the soil. There remains, 

 therefore, only one way of ascertaining whether we can 

 increase the yield by means of manuring ; and if so, 

 what kind of manure must be given. This is by 

 manuring experiments. 



Manuring experiments. It is often hardly possible 

 for the planter to make these experiments himself, and, 

 generally speaking, they should form part of the work 

 of Experiment Stations. The experiments will be 

 much more useful, their results will be obtained more 

 quickly and will be more reliable, when they have been 

 directed and controlled by experts in the science of 

 agriculture. But the planter has not always an Experi- 

 ment Station or an Agricultural Department at his 

 disposal ; a few indications as to the general method to 

 be pursued may therefore be given here. 



Where farmyard manure or compost or mulch is to 

 be had, it is obvious that the effect of these should first 

 be tried. In Europe 12 tons of farmyard manure per 

 acre (30 tons per hectare) is considered to be an 

 average dressing. When such a quantity cannot be 

 obtained and this is generally the case the experi- 

 ment has perforce to be made with as much farmyard 

 manure (or compost or mulch) as can be given per acre. 



Next, we have to find out whether an addition of 

 phosphorus or potash or nitrogen in some form is 

 useful ; and when no organic manure at all is available, 

 we have to make the experiments with artificial manures 

 alone. When this is the case the following quantities 

 may be recommended : 



As phosphorus manure . 200 kilograms of basic slag per acre (500 



kilograms per hectare). 

 As potash manure . 80 kilograms of sulphate of potash per 



acre (200 kilograms per hectare). 

 As nitrogen manure . 60 kilograms of sulphate of ammonia per 



acre (150 kilograms per hectare). 

 As lime manure . . 400 to 600 kilograms of carbonate of lime 



per acre"(l to 1J ton per hectare). 



