300 THE PRINCIPLES OF AGRICULTURE 



how necessary the moisture is and how it may 

 be caught and saved. In common speech, the 

 word cultivation is used for the stirring of the 

 soil; but it is better to use the word tillage, 

 since this is a specific technical word with no 

 other meaning. 



The present chapter has three co-ordinate 

 parts: (1) what tillage is; (2) what tillage does; 

 (3) how tillage is performed. 



Explain what you mean by the word tillage. Why is tillage 

 performed? Distinguish the two kinds of tillage (85>, Under 

 what conditions are these kinds practiced? What is meant by 

 deep and shallow tillage? By surface tillage? 



Note that tillage improves the land in three general ways. 

 (Read the first clause in the paragraphs ^7, 88, ^9.) How does 

 tillage improve the physical condition of the soil? What in- 

 fluence has it in saving moisture? What influence has it on the 

 chemical actions taking place in the soil? Of what importance is 

 air to the soil (89a)? In what sense is it true that "tillage is 

 manure"? 



Note that there are three general ways of performing tillage 

 with respect to the kinds of tools that are used. What are they 

 (§3a, 3b, 3ei? Give seven reasons why we plow. Explain how 

 plowing pulverizes the soil; tlie relation it Iims to green-manur- 

 ing; how it increases the depth of the soil; what relation it has 

 to hard-pnn or subsoil; how it modifies the temperature and 

 moisture of the soil; what relation it has to weathering. Explain 

 what subsoiiing is and what it does. Define the words furrow 

 and furrow-slice '91a). Describe what might be considered to 

 be an ideal general -purpose plow. 



Name the important surface-working tools. Give five im- 

 portant influences that surface-working has on the soil. What is 

 meant by the "earth-mulch?" What is it for? How deep should 

 it be? How is it made? How may it he destroyed? How is it 

 repaired? How often should it be repaired? If the earth-mulch 



