794 



Electro-Culture . 



At Harper Adams Agricultural College a screen of wire-net- 

 ting, 8 ft. high was fixed between the electrified area and the 

 control area during one season's experiments. 



Current. — The currents varied at the different stations with 

 different crops, and in the different years. Those in 1921 were 

 as follows: — At Lincluden, the discharge was given at the 

 rate of about 0.5 milliamp. per acre; the voltage (crest value) 

 was about 25,000. At Rothamsted two installations were sup- 

 plied from the same transformer, so that the current could 

 be controlled in one only, that over winter oats being selected. 

 With this crop the voltage (crest value) varied between 25,000 

 and 55,000 and the total discharge current was maintained at 

 the rate of 0.5 milliamp. per acre. The discharge given to 

 the clover grass varied from 0.2 milliamp. to 0.6 milliamp. 

 per acre. At Harper Adams Agricultural College also two 

 installations were supplied from the same transformer. With 

 oats the voltage (crest value) varied from 25,000 to 56,000, and 

 the current was kept at about 1.0 milliamp. With the pea 

 and oat mixture the current varied between 0.25 and 1.25 

 milliamp. per acre. 



Period of Discharge. — The periods during which crops were 

 subjected to the overhead discharge varied from 500 to about 

 900 hours. As a rule the period lasted from April to August 

 and the discharge was continued for 6 or 8 hours daily. 



Results of Field Experiments. — The results from different 

 crops in different years and at different stations are fully dis- 

 cussed in the four Interim Reports which should be consulted 

 for details. The accompanying table, however, gives a general 

 summarv of results of field exneriments from 1915 onw^ards 

 (those from 1918 being under the auspices of the Committee). 

 This summary does not include results obtained in 1921, the 

 dry weather of that year being unfavourable for field 

 experimental work. 



The data taken as a whole show that of the fourteen positive 

 results of experiments extending over six years only three are 

 less than 10 per cent., while of the four negative results none 

 reaches 10 per cent. Of the ten positive results with spring- 

 sown cereals only two are less than 10 per cent., and six 

 show an increase of 30 per cent, or over: while of the two 

 negative results both show decreases of less than 10 per cent. 

 The results of field experiments with these spring crops show 

 an average increase of 22 per cent. The effect of electrification 

 in increasing the yield of spring-sown oats and barley has thus 



