REVIEW QUESTIONS 



77 



(3) the rollers, of which there are the smooth iron roller, 

 the tubular roller, the clod crusher, the subsurface packer, 

 and the common planker; (4) the cultivators, which are 

 classified into the single- and the double-shovel cultivators, 

 the horse and the hand cultivators. In addition to the 

 above we can mention the garden spades, rakes, and hose. 

 All of these implements and tools are for the purpose of 

 putting the soil in the best possible condition as well as 

 maintaining the conditions necessary for plant growth. 



Fig. 24. — An eight-shovel riding cultivator. 



REVIEW QUESTIONS. 



1. What is cultivation? 



2. Is there any difference between cultivation and tillage? 



3. Why is cultivation important? 



4. Is it important to cultivate at a given time? 



5. What are the objects of cultivation? 



6. Discuss how cultivation aids in holding water in the soil. 



7. How does cultivation increase the bacterial action in the soil? 



8. Discuss how cultivation liberates plant food. 



9. What is meant by deep and shallow cultivation? 



