WEEDS AND THEIR CONTROL 



227 



.solution used is a two per cent, solution of Copper Sul- 

 phate (10 pounds to 50 gallons of water per acre). 

 These chemicals may be applied with either a hand or 

 power sprayer. Some men claim that Iron Sulphate 

 solution will kill all Mustards, Cow Cockle, Dandelion, 

 Canada Thistle, 

 Bindweed, Plan- 

 tain, Ragweed 

 and some other 

 weeds ; other in- 

 vestigators are 

 much less opti- 

 mistic regarding 

 the efficacy of 

 chemical sprays. 

 In any case the 

 'practice of 

 s p r a y in g for 

 weed control is 

 expensive and 

 has not yet 

 therefore come 

 into general use. 



Pasturing. — 



When pasture is short, sheep aid in controlling Mustard, 

 Plantain, Thistles, Lamb's Quarters, Shepherd's Purse 

 and many other weeds but they seldom touch Stinkweed 

 or Blue Burr. 



Smothering. — Leafy crops on spring plowing aid in 

 the control of Quack Grass by smothering. It is a fact 

 also that many young weed plants are prevented from 

 developing by the crowding and shading of a good stand 

 of any crop. This is why we find so many weeds where 



Fig. 79. — Dandelion. 



A typical tap-rooted perennial. A bad weed in 



lawns and waste places in Manitoba. 



