April, 1909. 



Edible Products. 



The above indicates that on the soils 

 on which the trials were conducted, 

 the manure which exerts a favourable 

 influence in the yields of cacao is a 

 mixture of superphosphate of lime and 

 sulphate of ammonia. Sulphate of potash 

 is not, indicated as being required, and, 

 in fuel, little good resulted from its 

 application. Nor has the use of sulphate 

 of ammonia by itself proved satisfactory. 

 In the mixed manuring of sulphate of 

 ammonia and superphosphate of lime 

 the cost of the sulphate of ammonia 

 was $7,50, that of the superphosphate 

 of lime fi2,50-~a total of |l0 per acre. 

 The increased yield of cacao presumably 

 due to the action of the manures during 

 the four years, was 168 lb. worth locally 

 at 12 c. per lb. $20-1(5. Allowing 6 per- 

 cent, per annum as interest on the 

 capital expended in the manures, we 

 get $7*76 as profit from the manuring. 



The following, in my opinion, illus- 

 trates some of the uncertainty which 

 attaches to manurial experiments with 

 cacao. The yields of cured cacao per 

 tree per crop during the period 1903-7 

 were as follows :— 



Not manured experimental beds 58 lb. 



,, ,, rest ot fields ... 72 ,, 

 Manured experimental beds ... 66 ,, 



The cause of the higher yields per tree 

 over the parts of the field not under 

 experiment, is that on them the bearing 

 trees are planted somewhat farther apart 

 from one another than they are on the 

 carefully selected beds used for experi- 

 ments with manure. 



In the preliminary determinations of 

 their yields during the selection of the 

 beds, it was found that the yields on 

 three beds selected for unmanured 

 control plots were 1*04, 1*38, and 1'20 lb. 

 of pulp per tree per crop. A fourth one, 

 with trees planted at the same distance 

 apart as were those on the three beds, 

 yielded 2 40 lb. of pulp per acre. If this 

 bed had been used as an uncontrolled 

 manured plot for manurial experiments 

 and any one of the other three as an un- 

 manured reference plot, we should have 

 obtained some striking result i dating 

 to the actions of manures on cacao. As 

 it is, reference to the figures given above 

 shows that the results obtained were, 

 as they are in all well-arranged agri- 

 cultural field trials, unmarked by pheno- 

 menal yields attributable by the experi- 

 menter to some special form of culti- 

 vation or of manure. 



My experience with cacao indicates 

 that to obtain reliable results the plots 

 used must be relatively large ones, con- 

 taining at least 100 trees on each, and 

 that each trial should be repeated on at 

 least three plots and preferably on four 



or five. Then the mean results obtained 

 over a series of crops although probably 

 not in any way striking, may be accepted 

 as fairly reliable. 



Discussion. 



Hon. W. Grahame Lang (Grenada) : 

 We in Grenada agree with Professor 

 Harrison's remarks as regards shade. 

 We find that wherever cacao is heavily 

 shaded, a good deal of disease exists ; 

 but as soon as the shade is removed the 

 cacao trees improve in condition. 



The President said that the question 

 of shade was a matter which had to be 

 treated according to local conditions. 

 No hard and fast rule or law could be 

 laid down with regard to any particular 

 district until actual trials had been made. 

 Side shade and shelter were necessary, 

 but overhanging shade was a matter in 

 which one must be guided by local 

 conditions. 



Professor Harrison, replying to the 

 Hon. G. W. Hazell, said that the usual 

 shade tr ee in British Guiana was Bois 

 Irnmortel, but they were now establish- 

 ing wind-breaks of rubber trees. 



Dr. Watts (Leeward Islands) said it 

 occurred to him that the question of 

 soil moisture and drainage was some- 

 what related to that of shade, and it 

 was questionable whether a great deal 

 of the beneficial effect attributed to 

 shade was not attributable to drainage 

 through the roots of the trees. From 

 what he had seen in one or two places 

 where he had taken careful note of trees 

 growing in damp situations, there was a 

 drainage effect which was beneficial 

 both in the case of lime and cacao trees. 

 In Dominica and Grenada cacao flourish- 

 ed much better without shade, whereas 

 in Trinidad they had a country which 

 was a great advocate of shade, and he 

 was not certain whether it was not 

 rather a questron of drainage. 



The President remarked that the point 

 raised by Dr. Watts was a very im- 

 portant one and deserved investigation. — 

 West Indian Bulletin, Vol. IX., No. 2. 



THE CULTIVATION AND MARKET- 

 ING OF MAIZE. 



{Concluded from •page 255.) 



Climate— Maize requires a high sum- 

 mer temperature and abundant mois- 

 ture, and attains its most luxuriant 

 growth where the summer is long con- 

 tinued, reaching a height of 20 feet and 

 more; but certain varieties of it are 

 adapted to take advantage of a short 

 but hot summer, and ripen in more 

 northern latitudes ; these, however, do 

 not attain nearly so great a height. Ic 



