226 



THE AGRICULTURAL NEWS. 



July 25, 1908. 



average of the past five years, is equal to 219 11). of 

 cured cacao per ac;re per annum over and above tliat 

 given by the unnianured plot. The net return obtain- 

 ed froTii manuring (after deducting the cost of the 

 manure) i:s, on t,he above basis, i-qual to ()4.--. 3(/. 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 It), 

 of dried cacao per acTe per annum, and a net monetary 

 profit of 105.S. dd. 



The highest return of all, however, was, it is 

 interesting to note, given by the plot that was mulciied 

 with grass and leaves. In this case the average gain 

 for the past five years 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 nudching treatment. 



The results obtained in 190()-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 

 residting from this method of treatment are cumulative. 

 During the season 1906-7 the mulched plot yielded 

 (54'S ft. of dry cured cacao in e.xcess of the unmanured 

 plot, which, on the basis already mentioned, represents 

 a net profit of 2()4.s. 



Further it is pointed out by Dr. Watts that when 

 the general health and growth of the trees on the i)lots 

 are taken into account, it is at once seen that the 

 individual trees on the mulched plot arc much finer 

 and better developed than those which received the 

 mineral maiuires. The soil which has recciwil the 

 mulching treatment is moist, friable, full nf humus, 

 and in a belter condition generally, as compared with 

 the other plots. It is also significant that the 

 unil'hed plot is well covered by trees planted at the 

 rate of lOS per acre, while the jjlot receiving no manure 

 requires l7cS trees per acre, or nearly 70 percent, more. 

 The trees on the plot receiving phosphate, potash, and 

 drieil blood come next to those on the mulched plot 

 as regards general health .nid condition. . Although the 

 dressings of leaves and ;/ ■• given such excellent 



results, it is pointed out llial. in many cases it will 

 probably be well to supplement mulching with moderate 

 ap))iications of nitrogen, and phosphate. 



The experiments carried out in the countr}- at 

 Pi'.-ard show beyond doubt that manures are beneficial 



in the establishment of young cacao plantations. The 

 use of pen manure brought about thi- best returns, 

 and the trees on the plots receiving this treatment 

 were more healthy and vigorous than on other plots. 

 Dried Wood and bone meal were also especially benefi- 

 cial, both in increasing the yield of cacao and in improv- 

 ing the condition of the trees, while considerably 

 increased returns, as compared with the no-manure plot, 

 were given by the trees to which basic phosphate and 

 ammonia, Itoth separately and in co'.nbination, were 

 applied. The trees on the plots manured with phos- 

 phate and potash, both separately and in combination^ 

 are described as b.'ing poor in foliage and lacking 

 vigorous growth. 



On one set of plots at Picard the utilization as 

 green dressings of the weeds growing under the young 

 cacao trees has proved of great value in maintaining 

 and improving the condition of the soil. The weeds 

 are allowed to grow until they reach a moderate size, 

 when they are either cut ilown .ind spread as a mulch, 

 or forked in. 



One of the chief conclusions that may already be 

 deduced from the residts obtained in these experiments 

 is the importance of keeping up and increasing the 

 supply of humus in the soil. For this leason, manures 

 siipplying organic matter, and especially pen manure,- 

 are particularly desirabh'. Nitrogenous mamires are 

 essential for cacao, as without nitrogen the trees lack 

 vigour: this constituent should prefer;).bly be given in 

 a slowly available foim, e.g., as dried blood or cotton- 

 seed meal. Phosphatic manures increase the crop, but 

 should not be used without nitrogen. As regards pot- 

 ash, this constituent is probably not urgently recpiired 

 as a manure for cacao in Dominica. 



SUGAR INDUSTRY, 



Analysis of Cane Juices from St. Kitt's 

 Estates, 

 lu reference to the note on cane juice analysis at 

 St.. Kitt's that appeared in a recent number of the 

 Ayrkidiural Nncs, Vol. VII, p. 184, the following 

 further particulars on the subject have been received 

 from Dr. Francis Watts, C.M.G. : — 



111 the past little or no infonnation ha.s been available 

 icsiiectiiii; the cliavactor or etiiciency of luuscovailo estate 

 working in St. Kitt's. In view of the interest at present 

 heinji shown in the question of the substitution of tho 

 t'entral factoi y sy.steni for the older uuiscovado method, it 

 lias become a matter of some importance that definite 

 information on this .subject should, if. possible, be acquired, 



