28 



BULLETIN 1379, U. S. DEPARTMENT OF AGRICULTURE 



These tabulated values are in many ways not subject to biometrical 

 analysis; they represent the results of experiments carried out with 

 varied complexes of soil, season, acreage, crop, and electrical treat- 

 ment. Nevertheless, in the absence of any definite knowledge con- 

 cerning the conditions under which an electrical treatment may be 

 presumed to be most effective there is perhaps no better index than 

 a comparison. 



Of 33 trials shown in Table 28, 21 indicate an increase for treated 

 areas, whereas 12 indicate a decrease. The treated areas return a 

 yield represented by the range 76 to 184 when the untreated areas 

 return a yield represented by 100 and give an average increase of 

 14 per cent. This increase is based upon yields reported for experi- 

 ments regardless of crop or seasonal normality, and Blackman esti- 

 mates the more reliable experiments as indicative of an average 

 increase in yield of about 22 per cent. In either case, such an in- 

 crease would seem sufficient to be of promise from an agricultural 

 standpoint. If an attempt is made to determine from these tabu- 

 lated values the conditions under winch the increases were obtained, 

 serious difficulties are immediately encountered. 



Unfortunately the normal productivity of the electrified and 

 control areas is in most c*ases unknown, and a serious lack of soil 

 uniformity is evident from the yields of different portions of control 

 areas. For example, in the 1919 and 1920 plats with oats at Lin- 

 cluden, which occupied the same areas for the two years, the control 

 yields were as shown in Table 29, in which the relative yields of the 

 corresponding treated areas for the same years, the controls being 

 taken as 100, are also shown for comparison: 



Table 29. — Comparison of the results of electrocidtural experiments with oat crops 

 at Lincluden, England, in 1919 and 1920 



Area 



Acre yields of control 

 plats (bushels) 



Relative yields of elec- 

 trified areas, the con- 

 trols being taken as 

 100 





1919 



1920 



1919 



1920 





45.2 

 43.8 

 28.9 



44.8 

 46.1 

 33.0 



80 

 102 

 184 



80 



II 



94 



III... 



156 







It is obvious that the yields of the third section of the control 

 area were uniformly low compared with the yields of the other 

 control sections and that this fact is almost certainly involved in 

 the high percentage increases arising for the third section of the 

 treated area. It would therefore appear that these particular 

 increases may be attributed to a lack of soil uniformity, and the 

 importance of this unknown factor is indicated. 



The most consistent series indicating favorable response to electrical 

 treatment appears to be the 1918 oat trials at Lincluden. The plats 

 in oats at Lincluden gave the average annual yields shown in Table 

 30. 



The yields from the electrified areas in 1918 seem to have been 

 sq exceptional compared with the electrified areas for the three 

 other years that one may question whether it is justifiable to attri- 

 bute tne increase solely to the electrical treatment. 



