Vol. XI. No. 273. 



THE AGRICULTURAL NEWS. 



323 



THE MANURING OF RUBBER TREES 



The following is an abstract, in the Bulletin of the 

 Bureau of Agricultural Intelligence and of Plant 

 Diseases, July 1912, of a paper by E. de Wildeman in 

 Le Caoutchouc et la Gutta-Ferclm for March 1.5, 1912, 

 p. 6037— 



It has been demonstrated that the use of a certain 

 amount of manure is necessary for the successful growing of 

 rubber trees. Some chemical compounds not only exert 

 a favourable action on the development of the trees, but 

 also on the yield of latex. Thus it appears from various 

 experiments, which however are not completely conclusive, 

 that nitrate of soda increases the flow of latex and the 

 proportion of rubber. 



At Hawaii .some manihots were manured with nitrate of 

 soda buried to a depth of i inches. The experiment was 

 conducted with three lots of manihots. The first was kep^ 

 as control, the second was manured with J-B). of the salt per 

 tree and the third i-B). per tree. The control trees yielded 

 during the experiment 1 to 2 oz. of dry rubber each; those 

 of the second lot 1 to 3 oz.; and those of the third lot 

 2 to 3 or., per tree. The effects of the nitrate begin to 

 show after forty-eight hours. [See Agricultural Fews, 

 Vol. X, p. 26.5.] M. E. Lierke has demonstrated that 

 potash ' plays a most important part in furthering the 

 development of heveas, but it must also be borne in mind 

 that manures, and especially potash, seem to favour the 

 development of plant parasites also. 



Among the rubber growers in the I'last, lime as a manure 

 raises at present the greatest interest. The value of lime 

 must be considered according to the soil in which the trees 

 are grown. In the Middle East the .soil is peaty, clayey or 

 sandy. In peat soils deep drainage is advisable, ;ifter which 

 the soil must be allowed to dry and then it is limed in order 

 to neutralize its acidity. Clay soils improve physically after 

 the addition of lime; they are easier to till and do not crack 

 after prolonged drought. In sandy soils lime improves the 

 cohesion. Lime acts also directly as plant food: it prevents 

 the development of the weeds which infest acid soils, and its 

 application may also become necessary after the repeated use 

 of other manures, such as sulphate of ammonia, kainit, and 

 superphosphates which, in the long run, produce a certain 

 amount of acidity in the soil. 



Lime further stops the development of fungi which 

 produce root rot, and especially of Foines semitostus, which 

 causes serious injury to heveas. 



It is recommended to slake quicklime with water, 

 allowing it to turn to a dry powder, and then to spread it 

 broadcast at the rate of about 5 cwt. per acre, and at least 

 four times as much on peat or clay. 



Experiments conducted in tropical regions where the 

 rainfall is abundant show that it is preferable to apply lime 

 and the other manures during the relatively dry season. 



In the Malay States the following formula is 

 recommended:— Quantity 



per acre. 



Slaked lime h *» 1 *»" 



Basic slag 350 lb. 



Sulphate of ammonia 150 „ 



Sulphate of potash 100 „ 



or kainit 400 „ 



or chloride of potash 100 „ 



Instead of salts of ammonia, castor oil, linseed, cotton 

 seed, earth nut [ground nut] or Hevea seed cake may be given, 

 and guano may be used instead of basic slag. 



Most crops grown between the Hevea trees appear to 

 retard their development and diminish the yield of rubber. 

 Tapioca [cassava], sugar-cane and pine apples exhaust the 

 soil considerably; coffee and cacao are not so harmful, 

 especially if the plants are kept at a sufficient distance. 



There is a good deal to be said both in favour of and 

 against the use of artificials or of green manures, and the 

 planter must judge according to his special conditions and 

 decide which type of manuring may be most useful, or 

 whether he may not preserve and improve the fertility of 

 the soil by 'clean weeding', and sterilize its surface by the 

 heat of the sun. This last method naturally requires 

 a great amount of careful labour which cannot always be 

 given. 



SOME USES FOR SUGAR. 



The Bulletin Agricol of Mauritius for April 1912 gives 

 a summary in an interesting manner of the many ways that 

 sugar is used in addition to its consumption as food and flav- 

 ouring, the information being based on an article by M. A. 

 Vivien, a well known French chemical engineer. On the 

 larger scale it is employed in tanning, particularly in con- 

 nexion with the use of chromic acid for preparing skins, for 

 d3-eing, the silver-plating of glass, textile manufactures, and 

 is even mixed with mortar and cement. Other large con- 

 sumptions of sugar are concerned with the making of 

 explosives, blacking, transparent soap, clear coco-nut oil, 

 white linens, and the regulation of the rate of emission of 

 acetylene gas. In America it is mixed vrith coke, in the 

 manufacture of briquettes and similar materials. By burning 

 it in a closed vessel, a form of carbon is obtained which is 

 useful for making electric arc 'carbons'. Sugar also enters 

 into the composition of many copying inks and gums. 

 Lastly, one of its chief means of consumption is in medicines. 

 It is claimed that sugar heated on a metal plate yields 

 6 per cent, of formaldehyde, and this appears to justify the 

 old method of disinfecting a room by burning sugar. 



The power of sugar as a preserving agent is well known, 

 and greater use of this ma)- be made, particularly for keeping 

 fresh meat and fish; a patent has actually been granted in 

 which a solution of sugar containing formalin or creolin is 

 employed for preserving eggs. In another way, cut flowers 

 may be made to keep fresh for a longer time by placing their 

 stalks in water containing 5 to 20 per cent, of sugar: for 

 roses the strength is 7 to 10 per cent.; for chrysanthemums 

 it is 15 to 17 per cent. There are flowers, however, such as 

 lilies, pelargoniums and sweet peas, which fade more quickly 

 in water containing sugar. 



The antiseptic properties of sugar are employed in wood 

 preservation by such means as the Powell wood process 

 (see Agricultural Neivs, Vol. IX, p. 201), and it enters into 

 many preparations intended for preventing the ravages of 

 fungi. Boilers and other steam-producing apparatus are 

 kept from 'scaling' by the use of preparations coutain- 

 ing sugar. Various useful organic acids are made with the 

 aid of that substance, and in the course of the preparation 

 of some of them gases possessing a high calorific value 

 (heating power) are produced; it is also employed in preparing 

 such acids by fermentation: among them are butyric acid, 

 yielding butyric ether which has the smell of pine-apples and 

 is used largely in the perfumery trade and in making syrups. 

 The matter in this account serves as a reminder of 

 a similar article describing many uses for cotton, devised ia 

 recent years, contained in the last volume of the Agricultural 

 Nevs, p. 246. 



