Vol X No. 232. 



THE AGRICULTURAL NEWS. 



91 



THE MEXICAN RUBBER INDUSTRY. 



An important report on a vi.sit by Mr. H. S. Sniitb, of 

 Tobago, to Mexico and Central America, for the purpose of 

 investigating the rubber industry, was pre.sented to the 

 Trinidad Board of Agriculture on January 20, 1911. 



In Mexico, Mr. Smith found that the care emi>loyed in 

 tapping the Castilloa plants varied niui-h on different estates; in 

 some ca.ses, this is done in the roughest niinner with a machete, 

 and notwithstanding the treatment, most of the trees seem 

 to be healthy, although there were evidences that many of 

 them had been killed through the drastic cutting that they 

 had received. On one estate, where careful tapping was done, 

 this was in the form of long V cuts, connected by a shallow 

 vertical channel, which carries the latex to a single cup at 

 the base of the tree. The method employed was to mark 

 the cut with the V tool, and to open it dcwn to the wood 

 with the point of a sharp knife. Intere.sting particulars of 

 results obtained by different methods of tapping are given in 

 the report. 



In parts of Mexico, much damage is done from time to 

 time by fires, some 83,000 trees having being burned recently 

 on one estate alone; and although these are making a good 

 second growth, the delay in tapping is a serious affair for 

 the company owning the estate. 



It is a matter of some interest that there are unmistak- 

 able indications that Castilloa thrive.? well when planted at 

 stake, closely, without shade. This has been the experience 

 from the early times, when plants were grown in the partial 

 shade uf forest clearings, and their growth was compared 

 with that of plants raised in nurseries, in the open. As 

 regards weeding, the old method was to keep the land absolut- 

 ely clean; at jjresent, the plan is to remove the weeds from 

 the vicinity of the plants alone, allowing them to come up 

 between the rows. 



Interesting experience is quoted from the Isthmus of 

 Tehuantepec, where it was found that Castilloa will not thrive 

 on a stifl' clay soil, or on low-lying, swampy land. It also 

 does not grow well on hilly land with a shallow snil, where 

 the dry season is long, and strong and hot winds are preva- 

 lent. A useful result of this experience has been to discourage 

 the flotation of bogus companies pretending to exploit Castil- 

 loa in impossible situations. 



A large proportion of the rublier produced in the 

 La Zacualpa group of estates is separated by means of a centri- 

 fugal machine, the best method having been found to be to 

 dilute the latex until it contains 1 per cent, of rubber solids, 

 and to allow it to stand thirty-six to thirty-eight hours before 

 it is placed in the machine, liubber prepared in this way 

 realizes about 4hd. per BE), more than crepe. 



In Panama, a different variety of Castilloa was found, the 

 chief particular characterics of which are the absence of hori- 

 zontal spreading of the branches — a quality which is usually 

 very evident in the case of the Mexican tree — and the fact 

 that the latex does not flow freely at any time. 



The conclusions made by Mr. Smith at the end of his 

 report include the following points: (1) that the varieties of 

 Castilloa in Mexico and Tobago are identical: (2) that Castil- 

 loa rubber can be produced as well in Tobago as in Mexico; 

 (3) information given by planters in Mexico shows that the 

 average yield of Castilloa trees ten to twelve years old, is nearer 

 -^- lb. per tree than 2 lb., as has often been supposed; (4) that 

 tapping higher up the tree will increase the yield considerably, 

 and the cost of production can be reduced materially liy the 

 adoption of Mexican methods of tapping; (5) that the rubber 

 from trees of similar ages is probably the .same in Mexico and 



Tobago, but that the former is likely to contain more resins 

 than the latter, on account of the fact that .some of it is 

 obtained from wild Castilloa growing in the plantations. 



A NEW GREEN MANURE. 



Seeds of a plant called Jioja Medelloa or Candida 

 Tejihrosia were distributed for trial last year among the 

 various experiment stations in the West Indies. A short note 

 on the plant appears in the Aiivicultural News, Vol. IX, 

 p. 311. 



The seeds of the plant were received from Ceylon, and 

 subsequently, particulars of the analysis of the plant, in 

 relation to its use as a green manure, have been obtained 

 from the Superintendent of Telbedde estate, Badulla, who 

 forwarded the seeds in the first instance. The figures given 

 for the green plant were determined from partly withered 

 leaves antl stems, so that allowance must be made for this; 

 the percentage of moisture is probably too low by about 20. 

 In the following table the figures are expressed as percent- 

 ages: — 



Leaves. Stems. 



Green plant. Plant dried Green Plant 

 at 100° C. plant, dried at 

 100° C. 

 Moisture 54-53 — 14 06 — 



Organic matter* 4286 94-27 8237 95-85 



Ash 2-61 5-73 3 57 4-15 



*Containing nitrogen 2.03 4-47 1'71 1-99 



The analysis of the ash shows that this contains the 

 following amounts for the leaves and the stems, taken in this 

 order: lime 17-69, 14-48 per cent.: potash 21-47, 3289 per 

 cent.; phosphoric acid 8-10, 11 '00 per cent. 



A consideration of the analysis is given which shows 

 that every 1,000 ft), of fre.sh green manure from the plant 

 supplies an equivalent, in nitrogen, phosphoric acid and potash, 

 to about 400 ftj. of castor cake, 10 lb. of bone meal, and 

 a similar amount of sulphate of potash, respectively. 



The investigation was made by the Analyst to the 

 Colombo Commercial Company, Ltd , and the opinion is 

 given that the figures compare very favourably with the 

 similar quantities for other green manures, with particular 

 reference to those published in the Circulars and Agricultural 

 Journil of the Royal Botanic Cardens, Ceylon, and it 

 is considered that, with a reasonable yield of material 

 per acre, the plant should jirove to be a very valuable green 

 manure. 



It is with much regret that the death of Mr. J. H. 

 Hart, F.L.S., late Superintendent of the Royal Botanic Gar- 

 dens, Trinidad, is placed on record. Mr. Hart had been 

 engaged directly in matters connected with agriculture in the 

 West Indies since 1875, first in Jamaica and then, from 1887 

 in Trinidad, where he occupied the post of Superintendent of 

 the Royal Botanic Gardens ur.til 1908, when he retired on 

 the maximum pension, and took up the work of an expert 

 adviser in tropical agriculture. Mr. Hart's keen interest in 

 almost all questions of tropical agiculture makes his death 

 a loss l)oth locally, and in regard to those parts of the world 

 where the matters on which he was an authority are of 

 first importance. 



