PLANT IMPROVEMENT, GOOD SEED 31 



grass, quack or couch grass, red field sorrel, Canada thistle, 

 and toad flax. Examples of bad weeds with fleshy under- 

 ground parts are: wild onions, garlic, curled or yellow dock, 

 dandelion, and many others. 



Fighting Bad Perennial Weeds. There are several 

 methods of fighting bad perennial weeds such as those men- 

 tioned in the preceding paragraph. 



1. In most cases the best method of fighting persistent 

 weeds is to practice very frequent tillage to prevent exposure 

 of the green leaves to the sunlight. This method is eco- 

 nomical when there is a crop on the land which is benefited 

 by frequent tillage, as corn, cotton, and garden crops. 



2. In some cases a dense growth of grain, millet, alfalfa, 

 or other close-growing crop may be effective in choking down 

 or smothering the weeds 



3. Smothering of small patches of weeds is sometimes 

 accomplished by means of straw stacks placed over them. 

 Tar paper may be used in some cases. 



4. Sheep in pastures will crop down many weeds and keep 

 them under control. Hogs confined in small areas will root 

 out many bad kinds of weeds and completely destroy them. 

 In small poultry yards weeds are kept in complete subjec- 

 tion by fowls eating off their tops closely. 



5. Frequent mowing of pastures, meadows, and yards 

 will aid materially in checking certain kinds of bad weeds. 

 It makes the grass grow better and retards asters, chicory, 

 plantains, hawkweed, dock, and many others. 



6. Chemicals are sometimes used on the crowns and roots 

 of weeds in yards, walks, roads, or where only a few weeds 

 have started. Chemicals used for this are salt, copper sulfate, 

 iron sulfate, kerosene, carbolic acid, and others. Salt on the 

 bad weeds in pastures often causes the cattle and sheep to 

 eat them down to get the salt. 



Spraying Weeds. Annual weeds, such as wild mus- 

 tard, corn cockle, and others that are bad in grain fields are 



