780 Summary of Agricultural Experiments, [dec, 



Destruction of Hedge Mustard (Biedermann' s Zentralblatt filr Agri- 

 kulturchemie, October, 191 1). — Calcium cyanamide, sulphate of iron, 

 and three patent preparations, were compared as to their relative effec- 

 tiveness in destroying hedge mustard which had strongly infested a 

 field of oats. 



Sulphate of iron was found to be the most effective material as well 

 as the cheapest. The quantity used for spraying was 53 gallons per 

 acre of a 22 per cent, solution. Calcium cyanamide was strewn over 

 the field at the rate of 80, 90, and 180 lb. per acre, the best results 

 being given by the largest quantity. 



Horticulture. 



Varieties and Pruning of Apples (Warwickshire C.C. Educ. Com., 

 Fruit Plot, No. 1, Ann. Rept., 1909-10). — Thirty-six varieties of apples 

 have been grown on the plot, and the crops of each in the four years 

 1906-9 are classified under the headings, "very heavy," "heavy," &c. 

 The pruning experiments are considered to have shown sufficiently 

 clear results to indicate the most suitable methods of dealing with 

 numerous varieties, when grown as bush trees on the Broad-leaved 

 Paradise stock, and directions are given for six methods of pruning 

 found most suitable for certain groups of varieties. 



Miscellaneous. 

 Effect of Atmospheric Impurities upon Vegetation near an industrial 



Town (Charles Crowther and A. G. Ruston, Jour. Agric. Science, 

 •vol iv., Pt. 1, May, 191 1 : Cambridge University Press). — This inves- 

 tigation comprises a three-years' series of analyses of rain collected 

 at Garforth, a twelve-months' series of analyses of rain collected in 

 Leeds, and researches into the effect of atmospheric impurities upon 

 vegetation. An extensive series of analyses of rain falling at Rotham- 

 sted has already been published, and these results are probably typical 

 of the essentially rural parts of the country, fairly remote from the 

 sea. The Garforth farm, however, is situated six miles from Leeds, 

 in the neighbourhood of coalfields, and the results obtained there may 

 probably be taken as applicable to the large tracts of agricultural land 

 situated in the smoke-infested localities so extensive in area in many 

 parts of the country. The Leeds samples were collected at ten different 

 stations, ranging from markedly industrial to purely residential sub- 

 urban districts. The following table shows in pounds per acre per 

 annum the dissolved impurities in the Garforth rain and in that of 

 the station in Leeds which had on the whole the most impure rain, 

 and the Rothamsted results are added for comparison : — 



Free 



Nitrogen. Sulphur. Chlorine. acid. 



Rothamsted 3*84 I7'4-I 14*87 



Garforth 8*37 957 20*89 20 



Leeds (Station 2) 15-5 215*0 198*0 90 



The nitrogen includes that brought down as nitrates and nitrites, 

 and not that in the form of organic matter, which amounted in 

 addition, to 1*56 lb. per acre at Garforth, 2*9 lb. at the Leeds station, 

 and 4*7 lb. at another station in Leeds. Estimations were also made 

 of the suspended matters (ash, tar, and soot) in Leeds rain, and the 

 amount varied at the different stations from 90 lb. to 1,886 lb. per 

 acre. The investigators observe that the outstanding feature of the 



