290 



[October, 1909. 



The staff at Coiinbatore will ultimately 

 include a botauist, an agricultural 

 chemist, a mycologist and an entomo- 

 logist, in addition to the Principal who 

 is also directly in charge of the experi- 

 mental farm. There are few subjects 

 in which research can be more pro- 

 fitably combined with research than 

 is the case with agriculture. Modern 

 methods, already proved profitable in 

 connection with the established cultiva- 

 tions of Europe and America, require to 

 be carefully tested in their application 

 to the products of a different zone and 

 climate ; and it is particularly desirable 

 that the teachers of agriculture should 



themselves have ample opportunities of 

 carrying out such tests ; whilst it is little 

 more than a truism to say that the pure 

 sciences are best taught by men who are 

 themselves engaged in extending the 

 boundaries of knowledge. 



In the above we are concerned solely 

 with the interests of education, since it 

 would carry us too far if we attempted 

 to deal with Coimbatore as an institu- 

 tion of research, From an educational 

 point of view we consider that Ceylon 

 has every reason to be envious of her 

 neighbour, 



R. H. L. 



GUMS, RESINS, SAPS AND EXUDATIONS. 



MANURING OF RUBBER. 



By George A. Bowie, m.a., b.sc. 



(From the India Rubber Journal, Vol. 

 XXXVII., No. 8, April, 1909.) 



The query as to how far the low vital- 

 ity and yielding power of many rubber 

 plantations is due to the want of proper 

 fertility can only be satisfactorily 

 answered after carrying out suitable 

 manuring experiments on the soils in 

 question. Although this is so, there can 

 be little doubt from the results of 

 experiments already conducted, com- 

 bined with a kowledge of the principles 

 of plant nutrition, that in many cases 

 the unsatisfactory state of affairs is 

 exclusively due to continued neglect in 

 manuring, or failure to restore to the 

 soil the chief elements of plant food, 

 viz., nitrogen, potash, phosphoric acid 

 and lime. It is quite true that in the 

 cultivation of rubber trees compara- 

 tively little in the way of these ingre- 

 dients is permanently withdrawn from 

 the soil, but the small amount that is 

 removed, chiefly in the latex and 

 macerated bai k, must be returned if the 

 plants are to maintain their normal 

 vigour and prolifity. No matter how 

 rich the soil may be at first, it is bound 

 to become exhausted, sooner or later, by 

 constant cultivation, and it should not 

 be forgotten that this stage is reached 

 earlier when tea or any other economic 

 crop, as is frequently the case, is grown 

 on the same ground. The question then 

 arises— what kind of manuring should be 

 adopted, or, in other words, in whac 

 proportions ard forms should the above- 

 mentioned ingredients be applied arti- 

 ficially to the soil in order to suit the 

 needs of the trees. 



In the first place it must be observed 

 that a heavy application of nitrogen is 

 apt to be followed by disappointing 

 results. An excess of this ingredient has 

 often the effect of stimulating the 

 growth of the foliage to such an extent 

 that the trunk becomes too weak to 

 support it, and the whole tree is bent 

 over by the force of the wind. To 

 prevent this and to obtain uniform 

 growth, it is strongly recommended to 

 restrict the quantity of nitrogen within 

 moderate limits, and to supplement it 

 with phosphates and specially with 

 potash which, according to the results 

 of numerous tests, exerts a particularly 

 beneficial influence on the wood of the 

 tree. 



The relation between the amounts of 

 nitrogen and potash applied has, no 

 doubt, a great deal to do with success in 

 the manuring of rubber trees. This is 

 well brought out in an experiment on 

 Hevea, conducted by Mr. R. M. Eckert, 

 Vincit, Ruauwella, Geylon. By the use 

 of a manurial mixture containing 6 per 

 cent, of nitrogen and 5 per cent, of 

 potash, the foliage was developed quite 

 out of proportion to the wood, with the 

 result that the trees were broken down 

 by the wind. A mixture containing 

 4 per cent, nitrogen and 15 per cent, 

 potash, produced, however, quite a 

 different effect, the trees presenting a 

 vigorous appearance and showing uni- 

 form growth. The firm and solid struc- 

 ture of their trunks was noticeable. 



The benefits accruing from the judi- 

 cious manuring of rubber are further 

 illustrated by the results of a carefully 

 carried out experiment at Deli-Moeda, 

 East Coast of Sumatra, Commencing 

 in Oatober, 1906, at which time the trees 

 (Hevea) were two years ten months old, 

 three plots of land were taken and 



