DECEMBER, 1908. j 



531 



Edible Products. 



that given by the unmanured plot. The 

 net return obtained from manuring 

 (after deducting tiie cost of the manure) 

 is, on the above basis, equal to (51s. 3d. 

 per acre. 



The combination of the organic and 

 the mineral manures, i.e., dried blood, 

 phosphates and potash, on the third 

 plot, has shown an increased yield of 

 374 lb. of dried cacao per acre per annum, 

 and at a net monetary profit of 105s. 9d. 



The highest return of all, however, 

 was, it is interesting to note, given by 

 the plot that was mulched with grass 

 and leaves. In this case the average 

 gain for the past five year's in dry cacao 

 per acre per annum over the unmanured 

 plot reached 402 lb. When the cost of 

 the manure has been deducted, there 

 remains a sum of 141s., representing the 

 net profit derived from the mulching 

 treatment. 



The results obtained in 1906-7 indicate, 

 however, that the average figures for 

 the past five years do not fully represent 

 the gain derived from mulching in cacao 

 plantations, and it would appear that 

 the benefits resulting from this method 

 of treatment are cumulative. During the 

 season 1906-7 the mulched plot yielded 

 648 lb. of dry cured cacao in excess of the 

 unmanured plot, which, on the basis 

 already mentioned, represents a net 

 profit of 261s. 



Further, it is pointed out by Dr. Watts 

 that when the general health aud growth 

 of the trees on the plots are taken into 

 account, it is at once seen that the indi- 

 vidual trees on the mulched plot are 

 much finer and better developed than 

 those which received the mineral 

 manures. The soil which has received 

 the mulching treatment is moist, friable, 

 full of humus, and in a better condition 

 generally, as compared with the other 

 plots. It is also significant that the 

 mulched plot is well covered by trees 

 planted at the rate of 108 per acre, while 

 the plot receiving no manure requires 

 178 trees per acre, or nearly 70 per 

 cent. more. The trees on the plot 

 receiving phosphate, potash, and dried 

 blood come next to those on the mulched 

 plot as regards general health and 

 condition. Although the dressings of 

 leaves and grass have given such excel- 

 lent results, it is pointed out that in 

 many cases it will probably be well to 

 supplement mulching with moderate 

 applications of nitrogen and phosphate. 



The experiments carried out in the 

 county at Picard show beyond doubt 

 that manures are beneficial in the 

 establishment of young cacao planta- 

 tions. The use of pen manure brought 



about the best returns, and the trees on 

 the plots receiving this treatment were 

 more healthy and vigorous than other 

 plots. Dried blood and bone meal were 

 also especially beneficial, both in increas- 

 ing the yield of cacao and in improving 

 the condition of the trees, whde consi- 

 derably increased returns, as compared 

 with the no-manure plot, were given by 

 the trees to which basic phosphate and 

 ammonia, both separately and in combi- 

 nation, were applied. The trees on the 

 plots manured with phosphate and 

 potash, both separately and in combi- 

 nation, are described as being poor in 

 foliage and lacking vigorous growth. 



On one set of plots at Picard the utili- 

 zation as green dressings of the weeds 

 growing under the young cacao trees 

 has proved of great value in maintain- 

 ing and improving the condition of the 

 soil. The weeds are allowed to grow 

 until they reach a moderate size, when 

 they are either cut down and spread as 

 a mulch, or forked in. 



One of the chief conclusions that may 

 already be deduced from the results 

 obtained in these experiments is the 

 importance of keeping up and increas- 

 ing the supply of humus in the soil. For 

 this reason, manures supplying organic 

 matter, and especially pen manure, are 

 particularly desirable. Nitrogenous 

 manures are essential for cacao, as with- 

 out nitrogen the trees lack vigour ; 

 this constituent should preferably be 

 given in a slowly available form, e.g., 

 as dried bio id or cotton-seed meal. 

 Phosphatic manures increase the crops, 

 but should not be used without nitro- 

 gen. As regards potash, this constitu- 

 ent is probably not urgently required 

 as a manure for cocao in Dominica. — 

 Agricultural Neios, Vol. VII., No. 163 

 July, 1908. 



THE FERMENTATION OF CACAO. 



By Oscar Loew, Physiologist. 



Although much has been written 

 about the fermentation of cacao, there 

 still exists a great difference of opinion 

 in regard to the process, its purpose and 

 necessity, and the kind of action involv- 

 ed in it. 



Herbert Wright, in his exhaustive 

 work on cacao,* mentions yeast cellst as 



* Theobroma Cacao or Cocoa. Colombo, " 1907, 

 p. 108. 



t According to A. Preyer (Tropcnflanzer, 5 

 (1901), pp. 157-173, a special kind of yeast, which 

 ho named Saccharomyces theobromac, effects the 

 bost fermentation in Ceylon, 



