54 WEEDS OF FARM LAND 



seeds with some deep-rooted plants such as chicory, burnet 

 and kidney vetch, since the latter send down large, strong 

 roots which open and aerate the land. Great success re- 

 warded the attempt. At the end of six years th^ plots of 

 grass from Elliott's mixture were ploughed up, and after 

 the most careful search hardly a single onion was to be 

 found, while the adjacent plots were so smothered with bulbs 

 and green tops that they gave the land a distinctly white ap- 

 pearance. Further experiments were made on the infested 

 area to compare the effect of a cheaper grass mixture, contain- 

 ing only Italian ryegrass and red clover, with that of the 

 more expensive " Elliott's mixture ". When the land was 

 ploughed up in 1916 l it was found that the cheaper mixture, 

 .in which deep-rooted plants were absent, had been far less 

 effective in eradicating the wild onion, while the Elliott's mix- 

 ture had brought about a complete clearance. 



When land is laid down to grass for the purpose of weed 

 eradication it is necessary to keep the pasture down for a 

 sufficient number of years in order that the underground parts 

 of the perennial weeds may have time and opportunity to 

 rot away. Such a clearance is not effected in a year or so, 

 but if it is to be thorough takes some considerable time. 

 Meanwhile the land will be producing hay crops and so will 

 not be running at a loss. 



() Eradication by Spraying and Manuring. Chemical 

 Means. During the past few years many attempts have been 

 made to combat weeds by various chemical means, the great 

 object being to find some application which will destroy the 

 weeds without injuring the crop. A considerable measure of 

 success has attended the experiments, but the natural con- 

 servatism of farmers has up to the present prevented the new 

 methods from being widely adopted, though some headway is 

 being made. 



The great factor that makes for success in this chemical 

 treatment lies in the difference between the habit of most 

 weeds and that of such crops as cereals. The long, narrow 

 upstanding leaves of cereals, which are often covered with 

 " bloom," tend to throw off rapidly any moisture that falls 

 upon them, with the result that even if they are treated with 

 a poisonous or corrosive substance injury does not necessarily 

 follow. The majority of weeds, however, have broad leaves 



^oelcker, J. A., "Occasional Notes" (February, 1918), Roy. Ag. Soc., 

 No. 4, pp. 1-3. 



