This question was not popular with the candidates and the performance of the few that
attempted it was discouraging.

In question 5(a), most ofthe candidates could not define ornamental plants. However, in
question 5(b), many candidates could list the factors that influence the choice of a crop
nursery site.

In question 5{c), most of the candidates were unable to give examples of physical, biological
and cultural methods of weed control. Further to this, most of the candidates could not give
the functions of potassium in crops as demanded in question 5 (d).

The expected answers include:

Meaning of ornamental plants

Ornamental plants are grown for their aesthetics, that is, their beauty, order and attractiveness.

Biological method
- Use of moth/beetle of Cactoblastic cactorum to control prickly pear (opuntia spp.)
- Use of ruminants such as goat and sheep to graze e.g. oil palm plantation
- Planting of leguminous crops such as Centrosema spp and Calapogonium spp on uncropped
land

Functions of Potassium in crops
- It is an essential constituent of plant tissues
- It aids synthesis of carbohydrate
- It activates various plant enzyme reactions
- It promotes the development of young plants
- It is necessary for neutralization of organic acids in plants
- It helps in nitrate uptake from the soil
- It is associated with stomata movement and therefore influences water relationship