178 



THE AGKICULTURAL NEWS 



Jr.NE 16, 1917. 



Rothamsted was wrongly prepared. The whole story 

 ■of humogen is unsatisfactory, e.Kcept for the fact 

 that impartial and carefully conducted experiments 

 by other workers have failed to obtain the effects 

 which its promoters claim for it. 



In regard to radium or radio-active substances, 

 which we may consider next, it was pointed out in 

 this Joumalf that a recent Bulletin^, issued by the 

 University of Illinois, gives the question of tl;e manurial 

 value of these substances general consideration. Upon 

 careful analysis of known facts, the writer of the 

 .Bulletin comes to the conclusion that radio-active 

 ■.substances cannot be depended on to effect an increase 

 in crop yields. We are scarcely prepared to dismiss 

 'the claims made for radio-active substances to this 

 •extent however, for, as we pointed out in a lengthy 

 summary of the position in this .Journal over 

 a year ago,* experunents in at least four different 

 countries have indicated that radio-active materials 

 stimulate growth: the results of experiments with peas, 

 for instance, have been remarkably uniform. The 

 trouble seems to be the expense of the materials, and 

 until the radium industry develops to such an extent 

 that radio-active by-products appear on the market — 

 substances like carnatite, for example — it is unlikely that 

 radium will ever play an important part in the economic 

 production of crops. Scientifically the subject continues 

 to be of great interest, and it may be mentioned here 

 that it is supposed that radium has the power to supply 

 energy, which can take the place of sunlight, for the 

 manufacture of sugar in the green plant. 



The role of dynamite in crop production is, of 

 course, entirely different to that of humogen or radium. 

 Its action is on the soil direct, and is of a mechanical 

 nature. It has been used principally in connexion 

 with orchard crops with the idea of aerating the soil. 

 The explosions are expected to form fissures in under- 

 lying rock, and to break up a hard-pan so that roots 

 can extend, and water and air may circulate. The 

 failure to obtain generally satisfactory results in 

 the West Indies in the case of cacao, limes and 

 bananas has probably been due to the fact that 

 explosions have been made when the subsoil was 

 .saturated with water. The effect of the explosion 

 under such conditions would be to consolidate rather 

 than to disintegrate. In any case the value of dyna- 

 mite as a soil improver cannot be said to be as great 

 as the promoters and the Press would have one 

 believe. It is unquestionably valuable in the clearing 

 -of forest land and in blasting hard rock that may 



+for Jlav 20. lOlC. p. 172. 



■ftNo. 177. 



♦March 27, i'-Hb (Vol. \IV. p. 111). 



interfere with ploughing, but only in very special 

 cases can it be expected to improve the air or 

 moisture conditions in the subsoil. 



The stimulation or speeding up of plant growth 

 by electric discharges has been left till the last, noc 

 because it is of less interest or importance: on the con- 

 trary, it is the method which holds out greatest pros- 

 pects of practical utilization. 



The latest report on experiments is by Professor 

 V. H. Blacknian and J. Jorgenseo, of the Imperial 

 College of Science and Technology.* The experiments 

 have been conducted principally with oats and clover, 

 and have now been carried on for two years. The 

 overhead discharge was applied by means of a series 

 of wires about 4J- yards apart and 7 feet from the 

 ground. The current applied was 3 amperes at 

 .50 volts, but the intensity of the discharge received by 

 the crop was much greater than in the previous year on 

 account of the closed arrangement of the wires. 



The investigators state that the effect of the 

 discharge on the crop was shown within a month after 

 germination, the treated plants being much higher and 

 of a darker green than those in the control plots. 

 Eventually the electrified area, as compared with the 

 control area, gave an increased yield of 20 bushels 

 (840 lb.) of grain and 2,80o lb. straw: in other words, 

 the increase in strain was -i9 per cent., and the increase 

 in straw was SS per cent. 



'After makmg allowance for the large experimental 

 error, it is clear,' the authors state, 'that oats under the 

 conditions of these experiments respond very markedly 

 by an increased ^-ield both in grain and straw to the 

 action of the overhead electric discharge.' 



It is not possible at present to estimate accurately 

 the financial results of the experiments. However, the 

 increased value of the oat crop worked out at over £6 

 per acre. The cost of the current used was about lis. 

 The cost of an installation on a commercial sale cannot 

 at the present time be predicted, but. as the authors 

 point out, the profit shown above would permit of 

 a heavy e.vpenditure on an installation. 



DEPARTMENT NEWS. 



By a ivcent steamer Mr. (i. A. .Jones, Assistant 

 Curator and Chemist of the Agricultural Department, 

 Dominica, left for England to offer his services in connex- 

 ion with the war. By the same steamer several planters 

 having estates in Dominica also embarked for the same 

 purpose. 



*Jov.rnal of Iht Board nf Agricidtnit (England and Wales), 

 for April 1917. 



