Vol. XV. No. 366. 



THE AGRICULTUKAL NEWS. 



149 



THE ENZYMES OF CACAO 



The Philippine Journal of Science, Vol. X, Sec. A, No. 2, 

 March 1915, contains an important paper by H. C. Brill on 

 the enzymes of cacao. Tests were carried out with three 

 ditferent kinds of extracts with a view to detecting the 

 presence or absence of well-known enzymes. Three series of 

 e.xperiments were run: namely, with an aqueous extract of 

 the surrounding pulp, an extract of the fresh seed, and an 

 extract of the clean fermented seed. 



It was found that the i)ulp surrounding the cacao bean 

 contains a greater number of enzymes than the fresh bean 

 itself. The pulp shows activity for the enzyme casease, 

 protease, oxidase raffinase and invertase. 



The fresh bean gave reaction for casease and rafBnase 

 and very strong reaction for oxidase. 



The fermented bean reacted for casease, protease, oxidase, 

 diastase, raffinase, and invertase. The fermented bean shows 

 the presence of protease and invertase, both of which are 

 absent in the fresh bean Taut present in tlije pulp. These 

 must have penetrated the membrane surrounding the bean 

 during fermentation. Diastase is present, but absent in the 

 extract from the fresh bean and from the surrounding pulp. 

 This has been developed in the bean itself during the process 

 of fermentation. 



Therefore the conclusion is reached that the presence of 

 these enzymes undoubtedly influence the character of the 

 fermentation, and a moderate temperature during the fermen- 

 tation is necessary in order that they may not be destroyed. 



THE MANURING OF CACAO IN BRITISH 



GUIANA. 



Inadvertently, reference was not made in this 

 Journal to the following results on the manuring of 

 cacao at the time they were published (October 1914) 

 in the Journal of the Board of Agriculture of British 

 Guiana. The summary, reproduced below, is taken 

 from the Bulletin of Agricultural Intelligence and 

 Plant Diseases, and shows verj' clearly the general 

 results obtained. These results hold good under con- 

 ditions similar to those obtaining at the Onderneem- 

 ing Farm, British Guiana. It will be noticed that 

 the safety of these results rests upon the fact that, 

 by use of the probable error, tlie mean minimum 

 increase that can occur has been determined. Thus, 

 although the returns from manurial treatment may be 

 more than those stated in the text, they cannot, in all 

 probability, be less. It will be observed also that 

 while mulching gives the largest increase, this increase 

 is not remunerative owing to the heavy cost of the 

 application. This point should be taken into account 

 when considering the results of uiulching in Dominica. 

 (See Reports on the Agricultural Department, D(jm- 



inica, and the West Indian Bidletin. Vol. XIV, 

 p. 81, et seq.) The cost of mulching per acre in British 

 Guiana is given as $GG. Under most conditions mulch 

 could be produced and applied at a considerably lower 

 rate than !?66 per acre. In fact, at this rate it would 

 pay to grow mulch and sell it to the cacao planter in 

 most places. 



Slanurial experiments carried out on cacao trees during^ 

 five years (1909-13) have furnished the following results : — 



Plots. 



Yields in 

 ft), per acre. 



Cured cacao. 



Probable 



error. 



Nos. 1, 4, 7, 11, and 16. No manure 2,080 ± 71 

 „ 3, 8, and 13. Heavily mulched 2,699 ± 113 

 ,, 12 and 18. Sulphate of ammonia 1,963 ± 155 

 „ 6 and 1 4. Superphosphate of 



lime and sulphate of potash 2,705 ± 154 



,, 5, 10 and 15. Superphosphate 



and sulphate of ammonia 2,375 ± 213 



No. 9. Sulphate of pota.sh and sul- 

 phate of ammonia 2,242 ± 217 

 Nos. 2 and 17. Superphosphate, sul- 

 phate of potash and sulphate of 

 ammonia 2,465 ± 99 



Taking into account the probable errors, the highest total 

 yield of cacao during the five years has been on the heavily 

 mulched plots, which gave a minimum increase of about 435 ft), 

 of cured cacao or about 84 ft), per acre over the mean of the 

 five control plots. 



The value of this increase is about 152, and the cost of 

 the mulching approximately $66. On the other hand, the 

 application of sulphate of potash and superphosphate of lime, 

 costing approximately $14 during the five years, gave a 

 minimun increase of 400 %. of cacao worth about $50. The 

 quick-acting nitrogenous manure — sulphate of ammonia — 

 somewhat lessened the yields both when applied alone and in 

 conjunction with superphosphate and sulphate of potash. 



The results obtained in 1913, during which no manures 

 were applied, showed that a residual effect remained from 

 the previous years only in the case of the mulched plots and 

 those receiving both superphosphate and sulphate of potash, 

 whilst, where sulphate of ammonia had been applied, the 

 yields were lower than in the case of the unmanured plots. 



Liming experiments carried out on thirty-six plots 

 showed no beneficial effect during the five years. 



The effect of decreasing the shade, improving the tillage, 

 drainage and sanitation of cacao trees is seen in the results 

 obtained from 2 acres of trees taken over by the Agricultural 

 Department in 1910. During the last five years the yields 

 have steadily increased from a mean of 1 ,064 ft), to 4,494 lb. 

 of cured cacao. Further experiments on the reduction of shade 

 were carried out in 1 9 1 3 on the same plots. 



The results were as follows: — 



Heavily shaded 

 Very lightly shaded 



Per acre of 300 trees. 

 No. of pods. lb. of pulp. 

 5,889 1,204 



9,546 1,823 



The writers consider that the removal of shade has 

 a greater influence on the yield of the trees than the improve- 

 ment in drainage and cultivation. 



