Differentiate between fumigation and spraying.

(i) What are the harmful effects of pesticides and fertilizers over a long period of time on soil?

(ii) Define Humus.

State two disadvantages of fertilizers.

(i) Write any two exotic (foreign) breeds of cow.

(ii) Write the names of any two popular varieties of marine (salt water) fish.

(iii) Name one indigenous and one exotic breed of fowl.

Describe the role of fertilizers and irrigation in improving crop yield. Mention any one effect of each if it used in excess.