V. FIELD WORK OR REFERENCE WORK 



Exercise I. Fertilizing 



(See also Experiments 95-98.) 



Visit a farm in early spring or in autumn before the fall 

 plowing is done. What is the reason for fertilizing the soil ? 

 What are the chief substances used for this purpose ? Which 

 ones are of mineral origin? Which are of vegetable origin? 

 What ones are supplied by animals? What is meant by 

 rotation of crops? Of what advantage is this? Find out 

 what crops may be so rotated. 



What crops exhaust the soil most rapidly? What kind 

 of fertilizers are best for corn, wheat, potatoes, tobacco, 

 cotton, and other staple crops ? 



How are the fertilizers applied to the soil ? What precau- 

 tions must be observed in using fertilizers? What chemical 

 elements are supplied by using lime, phosphates, bone fer- 

 tilizer, stable manures, wood ashes, and green clover? What 

 results if commercial fertilizers are used in excessive amounts ? 

 What fertilizers are best for gardens, for orchards, and for 

 lawns ? 



Exercise II. Tilling 



Describe a plow. How is it used? What is the object 

 of plowing? When is deep plowing used? When shallow? 

 How should the soil be turned ? Why should it not be com- 

 pletely inverted ? Find out three reasons for plowing. Why 

 is it best to pulverize the soil as much as possible in plowing? 



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