182 



The Supplement to the Tropical Agriculturist 



IMPORTANT DISCOVERY IN SOIL 

 FERTILISATION. 



BY ROTHAMSTED SCIENTISTS. 

 It is doubtless pretty generally known among 

 planters and the better educated of our other 

 agriculturists here that the fertilising properties 

 of 6oil consist largely in the amount of nitrogen 

 made available. It may not be so well-known 

 that the discovery of the fact that the formation 

 of nitrates in the soil was made by two for- 

 eigners, Messrs Schloesing and Muutz. At any 

 rate, if their names are not remembered, it 

 was their discovery that first led men to look 

 at the soil as the workshop of vast numbers 

 of living organisms which prepare food for 

 vegetable life. Even farmyard natural manure 

 would be of no value— or do distinct injury — to 

 crops, if it were not first broken up by soil 

 bacteria into simpler compounds, finally rea- 

 ching food that a plant can consume. The 

 effectiveness of this action depends on the re- 

 lative activities, subject to control by culti- 

 vation, of the various soil organisms. Another 

 great discovery was in 18Sb' by Messrs Hellrigel 

 and Wilfarth, who showed that certain bacilli, 

 associated with nodules on the roots of legum- 

 inous plants, could fix nitrogen. Since then 

 other bacteria have been found serving the same 

 purpose without having to be associated with 

 the leguminous plant. Gradually the knowledge 

 of changes undergone by organic matter rea- 

 ching the soil has been rendered more perfect, 

 but without any new point of view emerging. 



By the extra mail which reached Colombo on 

 the :25th November, however, we received infor- 

 mation of a fresh step made and a new factor that 

 has to be taken into account. Nearly twenty- 

 five years ago, it appears, an Alsatian wine- 

 grower injected carbon bisulphide into his 

 soil to destroy phylloxera, and was surprised 

 to find that not only was the pest removed but 

 the productivity of the sod increased. Little 

 attention was attracted by this discovery, al- 

 though recorded ; it was left as inexplicable. 

 The experiments, however, being repeated 

 with in the last year, it was proved beyond the 

 shadow of a doubt that iucreased productivity 

 is secured by heating or treatment with volatile 

 anti septics. A soil heated to water-boiling 

 point for two hours will double the crop that 

 it would bear without such treatment ; and 

 additional benefit is secured for four successive 

 crops. Treatment with carbon bisulphide, 

 chloroform and toluene for two days, on the 

 antiseptic being evaporated, increased the 

 yield 20 to 40 per cent, in nearly all cases of 

 soils and plants tried. The principle of these 

 discoveries was illuminated by the work of Doc- 

 tors Russell and Hutchinson of Rothamsted 

 Laboratory who discovered the distinguishing 

 feature of treated sods, namely, that they pro- 

 duced ammonia much faster from the nitro- 

 genous reserves of the soil. Plants feed on 

 ammonia and when they obtain the extra nitro- 

 gen, they can then get the requisite mineral 

 food from the soil. On the bacteriological side 

 the scientists verified that the heating wipes 

 out the nitrification bacteria which form 

 nitrates from ammonia ; but most other species 



survive in greatly reduced numbers, including 

 spore-producing organisms. The heating re- 

 duces the four to six million bacteria per 

 gramme of sod to a lew hundreds : treatment 

 with antiseptics to between one and two mil- 

 lions. When the soil is remoistened, the sur- 

 viving bacteria multiply at a rate never sebii in 

 untreated soil — up to 30 to 40 millions per 

 gramme in ten days or a fortnight. These bac- 

 teria are makers of ammonia out of the nitro- 

 genous organic matter, so their fertilisation 

 value is evident. The Doctors named thus found 

 that soil must contain a factor limiting the 

 number of bacteria to allow the bacteria free 

 play and that this factor must be put out of 

 action, 'ihe factor was discovered to be orga- 

 nisms of the protozoa class, amoeba, etc., 

 which live on, and are a thousand times larger 

 than, the ordinary bacteria. In the natural soil 

 an equilibrium is preserved ; but heating kills 

 them off entirely, and antiseptic treatment kills 

 almost all. The productivity of soil, therefore, 

 depends on the number of bacteria allowed to 

 have free play, unhampered by larger organisms. 

 Incidentally it is of interest to know that the 

 scientist, Metchnikoff, from whose cure ex- 

 Ceylon residents have recently derived so much 

 benefit at home, holds that the white cor- 

 puscles of blood, much like amoeba, keep us 

 healthy by devouring intrusive bacteria. But 

 the relation between the two powers in the 

 human body has to be reversed in the case of 

 the soil — for the maximum vitality and prolific 

 value to be secured. When the discovery re- 

 ferred to becomes fully utilised in practice, it is 

 impossible to estimate the vast increase in crops 

 that will be obtained thereby. The thanks of 

 agriculturists are due to Mr. J. F. Mason, M.P., 

 whose generosity brought about the Bacterio- 

 logical Laboratory at Rothamsted, and to the 

 Goldsmiths' Co. for a recent endowment which 

 brought Dr. Russell there to work. Meanwhile 

 all planters who are keen on their profession 

 and in the study of soil productivity should 

 obtain, from Messrs. A. M. & J. Ferguson, 

 Colombo, the book by Mr. A. D. Hall, f.k.s.. 

 Director of the Rothamsted Station, on Ferti 

 lisers and Manures. 



ECONOMIC PRODUCTS FROM FIJI. 



A number of mineral and vegetable products 

 have been received recently at the Imperial In- 

 stitute from Fiji for examination and valuation. 

 Several products now reported on are the out- 

 come of experiments. Some of these materials 

 were exhibited at the Franco-British Exhibition 

 last year; samples of all of them are now shown 

 in the Fiji Court of the Imperial Institute. 



Cocoa. 



Cocoa3 grown on two different estates were 

 received : — 



A. "Cocoa from Lami." The beans were 

 rather variable in size, and some were shriv- 

 elled ; the husks were of dull brick-red colour 

 due to " claying." 



B. " Cocoa from Levuka." The beans were 

 variable in size, and many were shrivelled. The 

 husks were pale to reddish -brown in colour, 

 and were not tl clayed. * 



