March, 1910.] 



235 



Scientific Agriculture. 



which has abnormally acid soil, render- 

 ing it unfavourable for the rapid growth 

 of root growth of rubber or other culti- 

 vated plants. 



The presence of a too large proportion 

 of acid in peaty soils is due to the exist- 

 ence of a large proportion of humie 

 acid which is a brown or black substance 

 produced by decaying vegetable matter. 

 This decomposition is greatly facilitated 

 by heat, air, and moisture, and by 

 the presence "of putrefying nitrogenous 

 matter. The conditions in many clear- 

 ings in Malaya are, therefore, specially 

 suited to the formation of an excess of 

 humic acid which exists in many places, 

 to such an extent, that the roots of 

 young rubber are not able to grow, and 

 the plants grow without vigour and in 

 some cases succumb. 



Such soils are physically and in other 

 respects most suitable for healthy and 

 rapid growth of rubber, and when the 

 amount of acid has been reduced, they 

 often produce exceptionally fine rubber, 



The question of the neutralisation of 

 such soils in the shortest time is of great 

 importance. The only method used at 

 present is to allow the sun free access to 

 the soil, and by this means and plentiful 

 drainage to gradually eliminate a pro- 

 portion of the acid. 



This is, however, a lengthy and not 

 always successful method, and a much 

 quicker plan is to add such proportion 

 of basic substance, such as lime, as is 

 needed to neutralize the acid in the soil. 



A very large supply of natural phos- 

 phate is being extracted from Christmas 



Island, and can be delivered compara- 

 tively cheaply at S. S. and F.M.S. ports. 



This raw phosphate not converted into 

 the superphosphate will be tried on acid 

 soils. The advantage in using this 

 manure is that the raw phosphate, i.e., 

 phosphatic rocks exactly as they are 

 obtained in nature is cheaper than the 

 manufactured superphosphate, and the 

 acid in the soil of the superacid lands 

 will convert the phosphate into super- 

 phosphate, and by so doing the soil will 

 more rapidly lose its acid and become 

 neutralized, and the available plant food 

 in the soil greatly increased. 



The costs of such an application of 

 raw phosphate will be determined by 

 experimenting with different quantities 

 per acre to discover the smallest amount 

 necessary to render the soil favourable 

 to root growth of rubber. 



In certain cases the lack of vigour in 

 the growth of young rubber on acid soils 

 has been attributed to dampness of soil, 

 fungi or other diseases of the roots, and 

 it will be well if in cases where there is 

 reason to suspect that the chemical 

 condition of the soil is the cause of the 

 lack of progress of rubber plants, a 

 portion of the field be treated to reduce 

 the acidity. 



On some of the super acid soils a 

 litmus paper pressed against a handful 

 of the damp soil gives in a short space of 

 time, some few minutes, a marked acid 

 reaction, i.e., is changed to a pink colour. 

 This may be used as a rough test of 

 the relative amount of acidity in the soil. 



MISCELLANEOUS; 



LITERATURE OP ECONOMIC 

 BOTANY AND AGRICULTURE. 



By J. C. Willis. 



Kapok :— 



Contribution a l'histoire botanique 



des Kapokiers. See Bot. Centr. 



150, p. 450. 

 Le Kapok aux Philippines. Journ, 



d'Agr. trop. June 1908, p. 187. 

 Kapok en Kapok-onderzoek. Ind. 



Merc. 21, 7, 1908, p. 533. 

 Some photographs of the silk cotton 



tree, and remarks on early records 



in America. Jam. Bull. 1907, p. 03. 

 Der Baumwollenbaum, Kapok. Der 



Pflanzer, IV. II. 1908, pp. 289, 305. 



30 



Le Kapok au Gamboge. L'Agric. 

 pratique des pays chauds, Feb. 1909, 

 p. 166, 



Kokoona : — 



Bark of Kokoona zeylanica. "T.A." 

 Nov. 1905, p. 697. 



Kola \- - 



Kola in West Africa. W. Ind. Bull. 



7. 1907, p. 338. 

 Le Kolatier en Guinee. Bull. Jard. 



Col. 1907, p. 400. 

 Kola Cultivation at the Gold Coast. 



Trop. Life, June 1907, p. 84. 

 Conservation et sterilisation des noix 



de Kola f raiches. Trav. Lab. Mat. 



Med. V. 1908. 



