ESTIMATING MANURIAL RESULTS 75 



irrespective of distance ; they are therefore to be 

 thinned out and left at as much as possible a uniform 

 distance of about 12 ft., and wider if possible " ; and " a 

 careful examination of all the plots at the present time, 

 however, shows that unless the greatest care is exercised 

 the figures of yields are rather misleading owing to 

 several reasons, the chief being the irregularity of the 

 bearing trees in each plot and the irregular cutting out 

 of diseased trees, and supplying of new ones during the 

 last few years." Also, " The manuring and improvement 

 of old cocoa is the chief object of the experiments ; but 

 as it is almost impossible to obtain identical conditions 

 on each plot, under those prevailing at Gangaruwa when 

 the estate was first taken over, it is better to look at the 

 matter from a general point of view, rather than to base 

 calculations of profit or loss on erroneous or misleading 

 figures." It is further pointed out that the manures 

 containing much nitrogen had a marked effect on in- 

 creasing the growth of foliage, and in the case of sulphate 

 of ammonia on the crop likewise. Even when certain 

 nitrogenous manures, such as blood meal, crushed fish, 

 castor and ground-nut cake were applied in conjunction 

 with basic slag and sulphate of potash, no marked 

 beneficial effect was observable in the yield. It is, 

 however, evident that sulphate of ammonia and a mix- 

 ture of sulphate of ammonia and basic slag are among 

 the best manures for cocoa. Good returns were obtained 

 the season following the f orking-in of leaves with an excess 

 of lime, but subsequently the yield deteriorated, and the 

 trees developed too much leaf growth. As the soil is 

 rich in lime applications of this material did not have a 

 beneficial effect upon the yield. 



The soil is poor in potash, but the results obtained from 

 the plots treated with potash manures are of rather an 

 uncertain nature. It is pointed out that there was a 

 tendency for manures to encourage a maximum yield 

 in December instead of November, maintaining the 

 increase until January ; thus indicating that a plentiful 

 supply of plant-food at the flowering and fruit-setting 

 period checked the dropping of immature fruits, and points 

 to the advisability of applying soluble manures im- 

 mediately previous to the principal flowering periods. 



