14 



soil culture particularly as a means of breaking up heavy sul)-soils. 

 Experiments were condunted at Kuala Lumpur rxovernment Planta- 

 tion with dynamite whei'e good results Avere obtained as regards 

 gii*th increase of young rubber. The greatest objection would 

 appear to be that of cost. 



Manuring. 

 The question of artificial fertilizei-s as applied to rubber is a 

 rather delicate one and requires to be carefully considered. As long 

 as good yields can be obtained by cultivation it is probably a mistake 

 to resort to manuring. At Castleton Estate, Telok Anson, an 

 extensive series of manuring tests are being conducted on good class 

 land and the results obtained so far would not appear to justif}' their 

 application, and many estates Avith x'ich soils would, in all probability, 

 behave in a similar way. There are, however, many cases Avhere it 

 would appear that manuring is to be recommended and the man 

 with long practical experience can^ generally discover those areas. 



A test was conducted in the Kuala Lumpur Gardens Avith young 

 rubber groAving on poor laterite soils Avitli the following results : 

 In the first year, the ti'ees in the manured plots, in every case, showed 

 a good excess in girth measurements over tlie trees in the 

 unmanured plots. In the second year, there was no manure applied, 

 and the aA-erage girth increases for this period were about equal to 

 that of the control plots, which goes to prove that the manui^es had 

 good effect for one year only. At the commencement of the third 

 year, a second application of similar manures was applied, and the 

 results for this year Avere also satisfactory but the excess was not as 

 large as that of the first year. In the fourth year, no fertilizers 

 were applied, and it was found that tlije manured plots had not given 

 as large an average girth increase as tlie control plots. In this 

 particular soil, the manures appear to have had a stimulating effect, 

 as regards growth, after each application, for about one year but 

 afterwaiTls there seemed to be a slight reaction. Over the four 

 years, however, the total girth increases of the manured plots in 

 every case considerably exceed that of the controls. At the close of 

 the four years tapping Avas commenced and it Avas found that the 

 control plots gave the poorest yields of rubber while the highest 

 yields Avere obtained from those manured plots which gave the 

 largest girth increases. Tliis is the result for the first nine mouths of 

 tapping and it will be interesting to see how long the high yields are 

 obtained. In the ninth month of tapping the manured plots continue 

 to give the proportionate excess of rubber over the unmanured plots, 

 and there seems no evidence at present of a declining superiority ; 

 rather the contrary. I have not tlie slightest doubt that the 

 fertilizers in this soil Avere beneficial, for we Avould appear to have 

 recovei'ed the costs of application in the first nine months of 

 tapping. It should be remembered that increase of gii^th means a 

 corresponding increase in length of tapping cut. 



