Edible Products, 



As a preliminary step we determined 

 the yields of cacao per tree in the fields 

 over the beds of cacao, each of which 

 is approximately one-third acre in area. 

 From among these we selected beds 

 having a mean of about 100 trees growing 

 on each) the numbers on them varying 

 from a minimum of eighty-eight to a 

 maximnm of 102, and upon which the 

 yields of cacao had been approximately 

 uniform. The beds are longitudinal, ex- 

 tending across the field from east to 

 west. By this means we selected as 

 apparently of equal productive power 

 sixteen plots for the experiment. 



Analyses of the soils of the plots 

 were made, which showed that they 

 were fairly heavy clay soils, although 

 lighter than the usual run of the cultivat- 

 ed soils on the coast-lands of Demerara. 



The following were the determinations 

 of the soil constituents usually consider- 

 ed as of importance :— 





% of air-dried soil, 





No. 1. 



No, 2. 



No, 3. 



Nitrogen 



•131 



•174 



•122 



Potash soluble in boiling hydro- 









chloric acid 



•482 



•589 



•502 



Potash soluble in 1 per cent. 









citric acid 



•0097 



■0043 



•2005 



Lime soluble in boiling hydro- 









chloric acid 



•233 



•245 



•248 



Lime soluble in 1 per cent 









citric acid 



•0342 



■0472 



•0390 



Phosphoric anhydride soluble 









in boiling hydrochloric acid 



•091 



•086 



•0G5 



Phosphoric anhydride soluble 









in 1 per cent, citric acid ... 



•0038 



0047 



•0025 



The analytical figures led to the ex- 

 pectation that applications of potash 

 salts and of phosphates were probably 

 necessary for the successful growth of 

 cacao on these soils. But the relatively 

 high proportion of potash present in a 

 state soluble in hydrochloric acid indi- 

 cated that tillage operations would pro- 

 bably render available sufficient of the 

 potash in the need of the plants. 



During the course of the experiments 

 very full and complete recoids were 

 kept by Mr. P. de Weever, Schoolmaster 

 at Onderneeming, who devoted much 

 time and great care in carrying out 

 the details of the experiments. 



The manures tried were : — 



1. Sulphate of ammonia. 



2. Sulphate of potash and super- 

 phosphate of lime. 



3. Sulphate of potash and sulphate of 

 ammonia. 



4. Superphosphate of lime and sul- 

 phate of ammonia. 



342 TApril, 1909. 



5. _ Sulphate of potash, superphosphate 

 of lime, and sulphate of ammonia. 



It was pointed out by me in 1904, that 

 the returns of cacao from the trees for 

 one season only would not represent the 

 actual action of the manures. The crops 

 were therefore determined during four 

 years from March, 1903, to April, 1907. 



The average number of pods, their 

 weights, and the average weight of cacao- 

 pulp yielded per tree per annum during 

 this period are shown by the following : — 



Per tree per annum- 



Manurial Treatment. 



Number 

 of pods. 



Pods, 

 weight 

 in pounds 



Weight 

 of pulp 

 In pounds. 



No Manure 



9 



7-4 



1-47 



Sulphate of potash and super- 





phosphate of lime 



9-2 



7-7 



1 58 



Sulphate of ammonia 



8-6 



7-1 



1-50 



Sulphate of potash and sul- 







phate of ammonia 



9-9 



7-9 



1-61 



Superphosphate of Lime and 







sulphate of ammonia 



9-4 



8-4 



T83 



Sulphate of potash, superphos- 





phate of lime, and sulphatt 









of ammonia 



99 



8'0 



1-70 



For the purposes of these experiments 

 Mr. de Weever during the year 1902-3 

 counted the pods produced on a con- 

 siderable number of beds on the Onder- 

 neeming cacao fields, determined the 

 weight of pulp yielded by them as 

 delivered at the sweating house, and the 

 weight of cured cacao obtained. 

 His results were : — 

 Number of pods ... 15,513 



Weight of pods ... 12,553 1b. 



Weight of pulp ... 2,555 „ 



Weight of cured cacao ... 1,016 „ 

 The cacao trees at Onderneeming on 

 the experimental beds are planted 

 approximately at 300 trees to the acre. 

 The yields of cured cacao per acre pe r 

 crop, calculated by the use of the above 

 data, work out as follows :— 



Manurial Treatment. ' YieId of cured 



cacao per acre. 



No manure ... ... jyg 



Sulphate of potash and superphosphate' 



of lime ... ,., i 



Sulphate of ammonia .. *.; 178 



Sulphate of potash and sulphate of! 



ammonia .. i igj 



Superphosphate of lime and sulphate 



of ammonia ... ... 218 



Superphosphate of lime, sulphate of! 



potash, and sulphate of ammonia. . I 202 



