544 



EXPERIMENT STATION RECORD. 



tricity upon vegetation are discussed at some length. It is argued that 

 normal atmospheric electricity is in some way beneficial to vegetation. 

 Lemstrom's experiments in Finnish Lapland and Spitzbergen in 1885, 

 and in Finland in 188G-'87, are quoted as proving that atmospheric 

 electricity applied artificially may exert a powerful influence upon 

 oTowing plants, the character of the influence varying with the species. 

 Some experiments in France in 1888 upon strawberries are brought for- 

 ward as showing that the simultaneous action of electricity and high 

 temperature is injurious to plants. — A. McAdie. 



Field experiments with sweet potatoes, F. H. Burnette {Louis- 

 iana Stas. Bui. 30, M ser., pp. 1052-1089). 



Synopsis. — These consisted of distance experiments in wliich the croi) was larj^est 

 when the plants stood 18 in. apart in 3J ft. rows; tests of best height of rows, 

 resulting in favor of ridges 16 in. high; experiments in moving and pruning 

 the fro win"' vines, by both of which operations the yield was reduced; tests of 

 cuttings from different parts of the vines and of different lengths, result- 

 ing in fiivor of cuttings from the terminal end of the vine and 24 in. in length ; 

 and variety tests. The yields and descriptions of 36 varieties tested are given. 

 The largest yiehl, 1,057.8 bu. per acre, was produced by the variety Providence. 

 Distance experiments (p. 1057).— The average yields for 3 years of 

 sweet potatoes grown at diiferent distances in rows 3J ft. apart were 

 as follows : 



Average yield j^er acre of stveet potatoes groivn at different distances. 



Distance in tlie row. 



Sin 



12 in 



15 in 



18 in 



24 in. (1893) 



Yield per acre. 



Merchant- 

 able. 



Bushels. 

 252. 07 

 258. 31 

 275.01. 



281.82 

 2-19. 08 



Culls. 



Bushels. 

 13.36 

 11.01 

 10. 48 

 11.71 

 15. 9G 



Height of ridges (pp. 1057, 1058).— The average yields for 20 years of 

 sweet potatoes grown on ridges of different heights were as follows: 



Average yield per acre of sweet potatoes grown on ridges of different heights. 



Moving and pruning sweet-potato vines (pp. 1058, 1059). — Vines left 

 undisturbed yielded 335.9 bu. of sweet potatoes per acre; lifted twice 

 per week, 314.5 bu., and pinched repeatedly to a length of 2 ft., 273.7 bu. 



