The Supplement to the Tropical Agriculturist 



operation ; and a doubtful one, because a few 

 drops of it art) not guaranteed to kilJ the grubs 

 through the whole soil radius of a cocoa tree, 

 and too much of it may damage the trees. It 

 is, however, recommended to be tried on trees 

 that are thought to be attacked by beginning a 

 yard out from the trees and at intervals round 

 each tree, ramming the fork in the soil, then 

 dropping a few drops of the Bi-sulphide in the 

 holo made by the prongs of the fork, drawing 

 earth over the holes at once. 



THE TREATMENT OF ACID SOILS FOR 

 RUBBER AND OTHER CULTIVATIONS. 



THE NEW RAPID SYSTEM OF 

 TAPPING RUBBER. 



We understand that the report on the new 

 system of extracting latex, referred to the 

 Messrs. Lee Hedges & Co.'s circular of Novem- 

 ber, (see page 591 of December T. A.) which 

 has' been prepared after witnessing a demons- 

 tration shortly before Christmas, has reached 

 Messrs. Lee Hedgbs & Co. from Joseph Eraser 

 and Clements. It is not above-named for a copy 

 of for publication. We understand, however, that 

 —though, of course, it is too soon yet to obtain 

 evidence as to how often the same surface may be 

 tapped by this system in a year, without injury 

 to the tree, or as to the effect on the tree after 

 some years' of numbers of tappings, the advan- 

 tages claimed have been established, namely : 



1) costof plant not above usual current methods; 



2) simplicity ; 3) reduced cost of production ; 



4) little— or no apparent— damage to the trees ; 



5) labour-saving ; and 6) quicker and possibly 

 increased returns. We believe the system can 

 be much varied or modified at will and is not 

 expected to be more fatal to the tree than 

 other methods (possibly the reverse) if it be 

 not employed entirely in order to extract the 

 maximum of latex in the minimum of time. 



Jan. 7th» 



Dear Sir,— In connection with the new tap- 

 ping' system of Messrs. Lee Hedges & Co., on 

 which Messrs. Joseph Eraser and Clements' 

 report is eagerly awaited, it is of interest to 

 recall that Mr. Petch, the Government Myco- 

 logist, has spoken against the use of the 

 pricker on several occasions, and, I understand, 

 he has not yet seen any reason to alter his 

 opinion. I hear, too, that the new method 

 of tapping rubber, which is now being boomed, 

 involves the use of the pricker. If it does, the 

 inventor must wait until he can demonstrate 

 what is the condition of the tree two years 

 •after tapping, before he can speak of the 

 success of his method. But Dr. Willis has 

 given his approval of the system, though I 

 cannot discover that he has considered the 

 pathological side— the structure and reactions 

 of a Hevea tree. I am strongly of opinion that 

 the use of the pricker causes the formation 

 of lumps on the renewed surface and makes 

 it untappable. You have only to look at the 

 trees Mr. Herbert Wright tapped at Henarat- 

 goda two years ago. —I am, yours faithfully, 



EXPERIENTIA DOCET. 



A series of experiments have been begun 

 by the Department of Agriculture on some Tow 

 lying flat land which has abnormally acid soil, 

 rendering it unfavourable for the rapid growth of 

 root growth of rubber or other cultivated plants. 

 The presence of a too large proportion of acid 

 in peaty soils is due to the existence of a 

 large proportion of humic acid which is a 

 brown or black substance produced by decay- 

 ing vegetable matter. This decomposition is 

 greatly facilitated by heat, air, and moisture 

 and by the presence of putrefying nitroge- 

 nous 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 ex- 

 tent 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 naturalisation of 

 such soils in the shortest time is of great im- 

 portance. 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 proportion 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 neutralise the acid in the toil. A 

 very large supply of natural phosphate is being 

 extracted from Christmas Island and can be 

 delivered comparatively 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 [pbosphato 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 con- 

 vert the phosphate into superphosphate and by 

 so doing the soil will more rapidly lose its 

 acid and become neutralised 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 tome of the super acid soils a 

 litmus paper pressed against a handful of the 

 damp soil gives in a short t>pace 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 amouut of 

 acidity in the soil. 



J. B. Carruthers. 

 — Agriyttlural Bulletin, for Jan., 19U9. 



