Vol. X. No. 250. 



THE AGRICULTURAL NEWS. 



379 



AGRICULTURAL MATTERS IN 

 BRITISH GUIANA. 



The Secretary of the Board of Agriculture of British 

 Guiana has drawn attention to an account of agricultural 

 matters that transpired at a ir.eeting of the Board of Agri- 

 culture held on October 24, 1911, and to a description of 

 experiments, mentioned at that meeting, carried out by the 

 Department of Science and Agriculture with respect to the 

 tapping of Sapium Jenmnni. The information appears respec- 

 tively in the Demerara Daily Chronicle for October 2.5 and 

 26, 1911, and the following matters of more general interest 

 are abstracted for use in the Agrkultural Xeira. 



At the meeting to which reference is made. Professor 

 Harrison, the Director of Science and Agriculture, informed the 

 Board that the following awards had been gained by British 

 Guiana, at the International Rubber and Allied Trades Exhi- 

 bition, London, namely the silver cup for the best sample of 

 balata from the West Indies, by the Consolidated Rubber and 

 Balata Estates Committee; and a similar cup for the best 

 specimen of cultivated rubber, by Plantation Noitgedacht; 

 the [irizes had been handed to the successful competitors by 

 His Excellency the Acting Governor. In continuation. 

 Professor Harrison, drew attention to the danger of permit- 

 ting the wild Hevea trees indigenous to the Colony {Hevea 

 confusa) to grow near or among H. lirasiliensis. Owing to 

 the similarity in the mode of bursting of the capsules it was 

 impossible to tell the difference between these two species. 

 The great danger, however, was that inferior hybrids would 

 be produced, and the final state would be the possession of 

 a mixture of J/. Ijrasilitnsis, II. confusa and a hybrid between 

 them. The importance of the matter was that not only would 

 such a condition lead to damage in regard to the ordinary inter- 

 ests of the estate.*, but that injury would be done by the 

 exportation of seeds to those who were expecting to get the 

 true seeds of H. hfusitiensis. 



A motion was adopted to the effect that a record should 

 be made, on the minutes, of the Boird's high appreciation of 

 the valuable services rendered at the International Rubber 

 Exhibition by Mr. F. A. Stockdale, its representative, and 

 by those who assisted him in the preparation of the exhibits; 

 and especially to Mr. Stockdale for the lecture he gave, the 

 interest he displayed, and the attraction which he made in the 

 space allotted to the Colony at the exhibition. 



Professor Harrison submitted his Annual Report as 

 Director of Science and Agriculture, and drew attention to 

 experiments that had been made in regard to the tapping of 

 Sapium trees; these receive consideration at a later stage of 

 this article. Tlie meeting concluded with the making of 

 a decision concerning the importation of certain live stock, 

 and with tlie giving of notice of a motion to be brought 

 forward in regard to the Wild Birds Protection Ordinance. 



As has been stated, details of the results of exliaustivo 

 tapping experiments conducted by the Department of Science 

 and Agriculture during the past three years with Sapium 

 Jenmani are contained in the later issue mentioned of the 

 Demerara Daily (JhrimicU. Tapping at different successive 

 periods always showed that the yield of dry rubber quickly 

 diminished, and the first results were supported by more 

 elaborate experiments in which trees of various sizes were 

 tapped. In the latter case the trees em[jloyed in the investi- 

 gations measured over ."lO inches in girth, between 30 and 



40 inches, and under 30 inches in girth. The first gave the 

 best yields, while the last afforded an exceedingly poor 

 return — not because they were young trees, but on account 

 of the fact that they were stunted in their growth. After 

 the trials, the yield of latex gradually became less, until it 

 ceased to How. In a general way, it was found that, during 

 a period of two years, 'the yield of dry rubber from matured 

 S. Jenmani trees, of varior.s sizes, from 30 inches to 92 inches 

 in girth, at 3 feet from the ground, the great majority of 

 them lieing between 40 inches and 70 inches in circum- 

 ference, was 18"33 oz. per tree.' 



Trials with retapping gave very poor yields of dry 

 rubber from the lower parts of the trunk, while they were 

 better on the higher parts, from S feet to 12 feet from the 

 ground. Professor Harrison drew attention to the gradual 

 deterioration in the quality of Sapium rubber that 

 arises from repeated tapping. That from the first tapping 

 was of excellent quality, but the product from the 

 second and third was sticky, and this unfavourable 

 characteristic increased until in some cases coagulation 

 of the latex was impossible. There was great variation in 

 the proportion of rubber in the latex; in 1908 it was about 18 

 per cent , in 1910 first tappings gave 15 per cent., while the 

 latex given liy trees that had been cut repeatedly during the 

 several periods contained about II per cent, of rubber. 



The general conclusions from the experiments are given 

 as follows: — 



(1) The trees yield latex very freely when first tapped, 

 and produce rubber of very high quality, not subject to 

 ' tackiness'. 



(2) The yields of latex, and consequently of rubber, 

 rapidly fall oft" during successive periods of tajipings. The 

 rubber obtained from later tappings is very subject to devel- 

 opment of ' tackiness', and this tendency increases with suc- 

 cessive tapping periods. 



(3) Some, if not all of the trees, when exhausted by 

 successive tapping periods, yield latex from which coagulated 

 rubber is not obtainable. 



(4) In a tapping period the main yields of latex and of 

 rubber are obtained in the first two or three tappings. The 

 trees run practically dry of latex in from three to six suoce.s- 

 sive parings. 



(5) No signs of wound response have been observed, and 

 in all probability it does not occur, in S. Jenmani trees of 

 mature age. 



(6) When the lower parts of the trunk of a repeatedly 

 tapped tree are practically exhausted of rubber-yielding latex, 

 the higher parts of the trunk yield latex in a relatively large 

 quantity. Whilst the rubber from the latex of the lower part 

 of the trunk may be very ' tacky', or more or less resinous and 

 coagulable with ditticulty, that yielded by the upper part is 

 of very good quality. 



(7) The tendency of ' tackiness' is far more noticeable in 

 biscuits prepared from the latex than it is in carefully pre- 

 pared coagulated ' scrap'. 



(8) In practical tappings of the .S'. Jenmani trees of 

 mature age, it is advisable to tap as great lengths of their 

 trunks as possible at one operation, and not to confine tapping 

 to the lower parts of them. 



(9) The wounds made in the bark of the trees during tap- 

 ping have been found to heal very slowly and unsatisfactorily. 



The article states finally that other matters are being 

 investigated by the Department in regard to <S'. Jenniani and 

 rubber production, and that information will doubtless be 

 available later from Mr. F. A. Stockdale, as a result of his 

 studies at Kew, concerning the species of Sapium, and of 

 Hevea, as well as of balata trees, indigenous to the Colony. 



