COCOA 205 



in yield obtained from pen manure and from mulch alone, 

 or supplemented by small additions of mineral manures. 

 Our tropical soils are deficient in organic matter or 

 humus-forming materials, and this is probably due to the 

 frequent surface washings to which they are subjected 

 by heavy torrential rains. Pen manure and mulching 

 material are, unfortunately, by no means abundant, and 

 are, therefore, expensive. 



Recording Results. 



In Trinidad yields are usually recorded in bags, of 

 165 Ib. each, per 1,000 trees. This probably arose from 

 the Spanish carree of land, an area of 3! acres, on which 

 ordinarily 1,000 trees were planted. The yield per acre 

 would now be a more satisfactory method in an English 

 colony, particularly when comparisons of the profits 

 derivable from the cultivation of different kinds of tropical 

 products are required. 



But in carrying out our experiments the old method 

 of reckoning had to be kept in mind, and our present 

 method of giving the yield in " pods per tree " provides 

 an easy comparison with the old method. If the number 

 of " pods per tree " is halved we get the yield " in bags 

 per 1,000 trees," if we assume that twelve pods are 

 equivalent to i Ib. of dry cacao. The number of pods 

 equivalent to i Ib. of dry cacao varies to some extent 

 on different estates, and especially during dry years, but 

 twelve may be taken as an average and convenient 

 number for ascertaining for experimental purposes the 

 approximate weight of dry cacao. The counting of the 

 pods does not entail much extra cost. The relation 

 between pods and weight should be checked at intervals. 

 The results of such a check are shown in Table I (p. 212), 

 which gives the figures obtained in different districts 

 during a year of low rainfall. 



In Table J (p. 213) the actual yields for five years on the 

 Government estate are given. It is a young estate and 

 contains trees of varying ages up to 30 years, and in one 

 field up to 80 years. The table shows the yield from 

 these trees of different ages, and before and during a 



