ELECTROCULTURE 17 



Plant-house experiments were also made on the effect of an electric 

 charge on the transpiration rate and the water requirement of plants. 

 The effect observed was well within the errors of experiment. 



The use of electrocultural methods in their present state of develop- 

 ment as a practical means of increasing the yield of crops in this country 

 is not recommended. 



REVIEW OF OTHER INVESTIGATIONS IN ELECTROCULTURE 



Electrocultural experiments may be divided into two main classes: 

 (1) Those in which the soil is the medium of conduction and (2) 

 those in which the air is the medium of conduction. Experiments of 

 the first class cover the use of soil currents resulting (1) from an 

 externally applied electromotive force, (2) from the galvanic action 

 of the soil moisture on zinc and copper plates buried in the ground, 

 and (3) from the use of metallic uprights designed to collect and 

 carry atmospheric electricity to the soil. Experiments of the second 

 class are those in which the normal air-earth current is increased by 

 means of a highly charged network over the plants or decreased by 

 inclosing the plants in a grounded cage made of metal screen. 



EXPERIMENTS WITH SOIL CURRENTS 



Among the first experiments with soil currents on a large scale 

 were those by Ross, prior to 1S44, (44) m New York. He buried a 

 copper plate 5 feet by 14 inches perpendicularly in the earth with 

 the 5-foot edge horizontal, and at a distance of 200 feet a zinc plate 

 of the same dimensions was similarly buried. The two plates were 

 connected above the ground, forming a galvanic cell. Potatoes were 

 drilled in rows between the plates and also in a similar plat without 

 plates. At the end of the experiment some of the potatoes from both 

 plats were measured, those from the treated plat averaging 2J^ 

 inches in diameter, while those from the control averaged only half 

 an inch. The total weights at harvest are not given, and conclusive 

 assurance that the two areas were of equal fertility at the outset is 

 lacking. The supposed beneficial effect is rendered doubtful through 

 the subsequent discontinuance of so simple a treatment. 



About this time Solly (46) conducted in England 70 small tests 

 similar in principle to those of Ross, the plates being 4 by 5 inches 

 and spaced only 6 inches apart. Grains, vegetables, and flowers 

 were planted between the electrodes. On comparing the appearance 

 of the treated and untreated plants a beneficial effect was recorded 

 in 19 cases, a harmful effect in 16 cases, and no effect in 35 cases. 

 Solly concluded that electricity has practically no effect on plant 

 growth. 



Fitchner (16) has recorded large increases from treatment with 

 galvanic currents. From his figures alone the experiments would 

 indicate increases of 16 to 127 per cent due to treatment. The 

 statement was made, however, that the treated plats were provided 

 with drains but that the control plats were not. Such conditions do 

 not constitute good experimental practice and leave the results open 

 to question. This same objection holds for accompanying experi- 

 ments on the decomposing action of the galvanic current on soil. 



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