200 FUNDAMENTALS OF AGRICULTURE. 



places if allowed to grow up to weeds often harbor 

 insects and plant diseases, as well as furnishing a sup- 

 ply of seed for the fields adjoining. A great deal of 

 care should be exercised in regard to the quality of the 

 seed sown. Often our worst weeds are scattered 

 from one part of the country to another in grain and 

 other farm seeds. All seed should be examined for 

 purity before being sown. 



EXERCISE. Name some weeds common to your locality. Name 

 those weeds which are easy to get rid of. Set aside a small plot 

 of ground which has some weeds growing on it and apply a saturated 

 solution of common salt. Have the pupils note the effect of the 

 salt on the weeds. If there is any wild mustard growing in your 

 neighborhood apply a 20 per cent, solution of iron sulphate to a plot 

 six feet square. The iron sulphate can be obtained at any drug 

 store. 



REFERENCES FOR COLLATERAL READING. 



FARM CROPS. 

 ROTATION OF CROPS : 



Yearbooks of the U. S. Dept. of Agriculture : 



1902 Practices in crop rotation. 



1908 Intensive methods and systematic rotation of crops in 



tobacco culture 

 Farmers' Bulletins, Nos. : 



144 Rotation of crops. 



337 Cropping systems for New England dairy farms. 

 Experiment Station Bulletin, No. : 



60 Delaware Cover crops as green manure. 

 CORN : 



Farmers' Bulletins, Nos. : 



81 Corn culture in the South. 



199 Corn growing. 



229 The production of good seed corn. 



253 The germination of seed corn. 



292 The cost of filling silos. 



303 Corn-harvesting machinery. 



313 Harvesting and storing corn. 



317 Shrinkage of corn in cribs. 



366 Corn breeding. 

 Experiment Station Bulletins, Nos. : 



204 North Carolina Some factors involved in successful 

 corn growing. 



Bulletins of the Middle West Experiment Stations. 

 COTTON : 



Farmers' Bulletins, Nos. : 



36 Cotton seed and its products. 



48 The manuring of cotton. 



