WAEC SSCE - Agricultural Science - 2009 (Practical)

Détails de la réponse

(a) Identification of specimens

• Specimen A: Sandy soil.
• Specimen B: Clayey soil.
• Specimen C: Earthworm.

(b) Three physical characteristics of specimens A and B

(c)(i) Specimen B (clayey soil) is recommended for pond construction.

(c)(ii) Clay has a very high water-holding capacity and does not lose water through percolation easily, so it makes the pond water-tight.

(d) Two ways of improving Specimen A (sandy soil) for crop production

1. Mulching to reduce evaporation and conserve soil moisture.
2. Planting cover crops or applying green manure to add organic matter and improve fertility. (Liming and fallowing are also acceptable.)

(e) Two ways Specimen C (earthworm) is of economic importance in agriculture

1. By burrowing it loosens the soil and increases aeration, water infiltration and percolation, giving roots easy penetration.
2. It drags plant remains into the soil and increases its organic matter content, thereby improving soil structure and fertility and raising crop yields.

Détails de la réponse

(a) Identification

• Specimen K: Rhinoceros beetle (adult beetle, order Coleoptera), recognised by the hard black exoskeleton, the prominent horn on the head and the hardened forewings (elytra) covering membranous hind wings.
• Specimen L: Rat (a rodent), recognised by the covering of fur, the long scaly tail, the chisel-like continuously growing incisors and the four clawed limbs.

(b) Three crops commonly attacked by each

Specimen K (rhinoceros beetle):

1. Oil palm
2. Coconut palm
3. Raffia palm (it also attacks yam, cocoyam and banana)

Specimen L (rat):

1. Cassava
2. Groundnut
3. Cereal grains, whether in the field or in store (it also eats vegetables, oil palm, banana, yam and sweet potato)

(c) Three types of damage caused by each

Specimen K (rhinoceros beetle):

1. It bores into the developing spear and growing point of young oil palm and other palms.
2. The bore holes serve as entry points for secondary rot infection and reduce the quality of the produce.
3. Severe crown damage can kill the growing shoot, causing young palms to break, lodge or die.

Specimen L (rat):

1. It eats up young plants, cereals, groundnuts, roots and tubers of crops.
2. Its burrowing destroys crop roots and causes plants to lodge, reducing yield.
3. It contaminates produce with its faeces and urine, and its gnaw wounds admit secondary infection.

(d) Two ways of controlling each

Specimen K (rhinoceros beetle):

1. Cultural and physical control: hand-pick the beetles from the crown and destroy felled palms and stumps by burning to remove the breeding sites.
2. Chemical or biological control: apply an approved insecticide into the leaf axils, or introduce natural enemies such as the Oryctes virus.

Specimen L (rat):

1. Set traps and rat-proof the store, and use repellents.
2. Poison with rodenticides, or use biological control with predators such as cats.

Détails de la réponse

(a) Identification of the specimens

• Specimen O: Animal horn.
• Specimen P: Animal skin (hide).

(b) Three farm animals which do NOT possess specimen O (horn)

• Poultry (domestic fowl)
• Pig (swine)
• Rabbit

(Guinea pig, donkey, horse and camel are also acceptable.)

(c)(i) Two farm animals in which BOTH sexes possess specimen O (horn)

• Cattle
• Goat

(c)(ii) One farm animal in which only ONE sex possesses specimen O (horn)

Sheep (in many breeds only the ram is horned while the ewe is polled).

(d) Two functions of EACH specimen to the animal

(e) Three problems in managing horned animals (specimen O)

1. The animals may injure the owner, herdsmen or one another with the horns.
2. Horns cause problems of space during transportation and require larger housing/pen space.
3. Horned animals bully hornless animals and the young ones, and may use their horns to destroy buildings and other farm structures.

Détails de la réponse

Specimens: H (spade), I (secateurs), J (open-ended spanner).

(a) Two farm tools that perform similar functions to each specimen

• Specimen H (spade): shovel and hand trowel.
• Specimen I (secateurs): pruning saw and pair of shears (sickle).
• Specimen J (open-ended spanner): ring spanner and adjustable (monkey) wrench.

(b) How specimens I and J are used

• Specimen I (secateurs): open the handles to widen the blades, place the opened blades against the stem or branch to be cut, then press the handles together so that the sharp blade cuts cleanly through the material for pruning or harvesting soft twigs and fruits.
• Specimen J (open-ended spanner): fit the open jaw of the correct size squarely over the head of the nut or bolt, then turn the handle clockwise to tighten or anticlockwise to loosen, continuing to turn until the bolt is firmly fixed or freed before releasing.

(c) Description of specimens H and J

• Specimen H (spade): it has a long wooden or metal handle whose upper end widens into a triangular or D-shaped grip for firm handling; the blade is of steel, flat and rectangular, with a sharp lower edge for penetrating the soil.
• Specimen J (open-ended spanner): it is a metallic tool with a flattened elongated handle, having an open jaw at each end shaped to fit the hexagonal heads of bolts of various sizes.

(d) Four advantages of using farm tools for farm work

• They make work easier and minimise drudgery.
• They ensure faster completion of operations and save time.
• They increase the farmer's productivity and the quality of work done.
• They minimise injury to the farmer and are easy to operate and maintain.