WAEC SSCE - Agricultural Science - 2017 (Practical)

Antwortdetails

The specimens are identified in the question: P (aphid), Q (cowpea seeds) and R (coconut fruit).

(a)(i) Three effects of specimen P (aphid) on crops:

• It sucks plant sap, causing wilting, yellowing and stunted growth.
• It transmits viral diseases from plant to plant.
• Its sugary excreta (honeydew) encourages sooty mould, which reduces photosynthesis and yield.

(a)(ii) Two ways of controlling specimen P (aphid):

• Spray with an appropriate insecticide (contact/systemic).
• Encourage/use natural enemies such as ladybird beetles (biological control) and plant resistant varieties.

(b)(i) Two benefits of including the crop from which specimen Q (cowpea, a legume) was obtained in a mixed cropping system:

• It fixes atmospheric nitrogen through its root nodules and enriches the soil.
• It provides ground cover that reduces soil erosion and weed growth, and gives extra food/income.

(b)(ii) Major storage pest of specimen Q (cowpea): The cowpea weevil / bruchid, Callosobruchus maculatus.

(c) Five uses of specimen R (coconut):

• The white kernel is eaten as food.
• The coconut water is a refreshing drink.
• Oil is extracted from the kernel for cooking, soap and cosmetics.
• The husk (coir) is used to make ropes, mats and brushes.
• The hard shell is used for making cups, ladles, charcoal and ornaments.

(d) Botanical names:

• Specimen Q (cowpea): Vigna unguiculata.
• Specimen R (coconut): Cocos nucifera.

Antwortdetails

The specimens are identified in the question: I (wheelbarrow), J (file), K (palm oil) and L (cotton lint).

(a)(i) Two uses each of specimens I and J:

Specimen I (wheelbarrow):

• For carrying/conveying farm inputs such as manure, seeds and tools.
• For conveying harvested produce and farm refuse within the farm.

Specimen J (file):

• For sharpening the cutting edges of tools such as cutlasses and hoes.
• For smoothing/removing rough edges from metal and wood.

(a)(ii) Two general ways of maintaining specimens I and J:

• Clean them after use and store them in a dry shed to prevent rust.
• Oil/grease the metal parts (and the wheel of the wheelbarrow) and repair or replace worn parts.

(b)(i) Botanical names of the crops:

• Specimen K (palm oil) is obtained from the oil palm, Elaeis guineensis.
• Specimen L (cotton lint) is obtained from cotton, Gossypium hirsutum.

(b)(ii) Steps in the traditional method of producing palm oil (specimen K):

1. Harvest ripe oil-palm fruit bunches and allow them to ferment for a few days.
2. Strip/detach the fruits from the bunches.
3. Boil the fruits in water to soften the mesocarp.
4. Pound the boiled fruits in a mortar (or trample) to separate the fibre, nuts and pulp.
5. Mix with water and squeeze/knead so the oil floats to the surface.
6. Skim off the floating oil and boil it again to remove water, then allow to cool and store.

Antwortdetails

The specimens are identified in the question: T (chicken egg) and U (tilapia fish).

(a)(i) Three breeds of the farm animal (domestic fowl) that produces specimen T:

• White Leghorn
• Rhode Island Red
• Plymouth Rock (or Sussex)

(a)(ii) Four ways in which specimen T (egg) is economically important:

• It is a rich source of animal protein in human diet.
• It is sold to earn income for the farmer.
• It is hatched to produce chicks and increase the flock.
• It is used as raw material in industry (for making vaccines, confectioneries and cosmetics).

(b)(i) Two methods of harvesting specimen U (tilapia) from the pond:

• By using nets (seine/cast/drag nets).
• By draining the pond and hand-picking the fish (or by using hooks/traps).

(b)(ii) Two by-products from processing specimen U:

• Fish meal (from waste and offal, used in animal feed).
• Fish oil (and fish manure/skin).

(b)(iii) Four methods of preserving specimen U (fish):

• Smoking
• Sun-drying
• Salting
• Freezing/refrigeration (or canning)

Antwortdetails

(a) Specimen E (NPK 15:15:15):

• (i) Three major nutrients supplied to crops: Nitrogen (N), Phosphorus (P) and Potassium (K).
• (ii) Three methods of applying specimen E on a farm:
  • Broadcasting (spreading evenly over the field).
  • Band placement/side dressing (placing beside the rows or plants).
  • Ring/spot application (placing around each plant).

(b) Three agricultural uses of each of specimens F and G:

Specimen F (wood ash):

• Used to supply potassium (potash) to the soil.
• Used to reduce soil acidity (as a liming material).
• Used to control storage pests of grains and legumes.

Specimen G (limestone):

• Used to reduce soil acidity (raise soil pH) - liming.
• Supplies calcium and magnesium to the soil.
• Improves soil structure and the activity of soil micro-organisms.

(c) Three ways in which specimen H (cow dung) is important to the soil:

• It adds plant nutrients and improves soil fertility.
• It increases the organic matter/humus content and improves soil structure.
• It improves the water-holding capacity and aeration of the soil and feeds soil organisms.