(a) (i) Define the term soil tillage. [2 marks] 
(ii) Distinguish between primary tillage and secondary tillage. [2 marks] 

(b) Outline three roles of each of the following soil management practices: 
(i) Green manuring; 
(ii) Mulching. [6 marks] 

(c) Give six reasons for carrying out irrigation in crop production. [6 marks]