(a) What is meant by allotropy?       (1mk)

(b) Identify the two crystalline allotropes of carbon.       (1mk)

(c) Give one use of carbon black.     (1mk)

(a) Describe six advantages of rotational grazing (6mks)
(b) Explain eight ways in which soil fertility can be maintained (8mks)
(c) Explain six reasons for pruning coffee.(6mks)

(a) Describe paddy rice production under the following sub-headings.
i) Land preparation  (2 mks)
ii) Water control  (2 mks)
iii) Fertilizer application (2 mks)
iv) Weed control (2 mks)

(b) Explain how each of the properties of rainfall and light influence crop production. (8 mks)
i) Rainfall
ii) Light

(c) Explain four factors that should be considered when sitting a vegetable nursery. (4mks)

(a) Explain five factors that should be considered in farm planning. (10 mks)
(b) Describe transplanting of tomatoes seedling. (10 mks)

Below is a graphical representation of a law in agricultural economics. Study the graph carefully and answer the questions that follow.

a) State the law illustrated by the graph (2mks)

b) Explain how each additional unit of fertilizer input relates to the total output of maize in phases II and III .( 2 mks)

Phase II
.....................................................................................................................................................

Phase III 
......................................................................................................................................................

c) State the importance of the law identified in ( a ) above to the maize farmer (1mk)

The diagram below shows a maize cob attacked by a certain disease. Study it and then answer the following questions.

(a) Identify the disease     (1 mk)

(b) Name two causal organism of the disease. (1 mk)

(c) State three cultural methods of controlling the disease. (3 mks)

(a) Distinguish between straight and compound fertilizers. (1mk)

(b) A farmer applied 200kg of C A N (20%N) per hectare maize crop. Calculate the amount of Nitrogen applied on his 5 hectare crop. Show your working (4mks)

The diagram below shows a pest and the damaged crop study it and answer the questions that follow.

a) Identify the pest illustrated above (1mk)

b) Explain two ways of controlling the pest (2mks)

c) State two ways in which the pest economically important. (2mks)

Give four suitable characteristics of plants used as green manure. (2mks)

Give three reasons why primary cultivation should be done early before the onset of the rains(1 ½ )