PLANT FOODS 149 



Problems 



1. How many pounds of each of the three impor- 

 tant fertilizers in a crop of wheat that yields 20 bu. 

 per acre? 25 bu. per acre? 



2. A corn crop of 50 bu. per acre ? 60 bu. ? 75 bu. ? 



3. An oat crop of 40 bu. per acre ? 50 bu. ? 60 bu. ? 



4. A barley crop of 40 bu. ? 45 bu. ? 50 bu. ? 



5. A potato crop of 110 bu. per acre? 120 bu. ? 

 150 bu. ? 



6. A clover hay crop of 3y 2 tons per acre? 4 tons? 

 5 tons? 



7. A meadow hay crop of 2 tons per acre? 2 l /2 

 tons ? 3 tons ? 



8. A tobacco crop of 1,500 Ibs. per acre? 1,800 

 Ibs.? 



9. Compare the results and notice which crop is 

 hardest on the soil. 



10. Pupils should furnish data for similar prob- 

 lems. Tell how many acres of corn, wheat, hay, etc., 

 were raised on the farm at home, the number of bush- 

 els or tons per acre, and find the amount of the three 

 essential fertilizers taken off with the crop. 



LESSON XLVIII 



FERTILIZERS 



During this month we shall begin the work of fertiliz- 

 ing on our farm. We shall mix the commercial fer- 

 tilizers in our farm laboratory. Barnyard manures and 

 other fertilizers must be spread upon the orchards, 



