WAEC SSCE - Agricultural Science - 2003 (Practical)

(a) Identification of specimens

• Specimen L: Urea (a nitrogenous fertilizer).
• Specimen N: Lime (quicklime / slaked lime).
• Specimen Q: Wood ash.

(b) Three agricultural uses of each of specimens N and Q

Specimen N (Lime):

1. It is used to correct soil acidity.
2. It supplies calcium for root development and improves the structure of clay soils.
3. It is used to correct water acidity and reduce turbidity in fish ponds by flocculating fine clay particles.

Specimen Q (Wood ash):

1. It is used to correct soil acidity.
2. It provides potassium for plant growth and is a good component of compost.
3. It serves as a natural pesticide for controlling insect pests of seedlings and vegetables (and increases phytoplankton growth in fish ponds).

(c) Two crops each that require the specimens in large quantities for good yields

(d) Three methods of applying specimen L (urea) on a farm

1. Ploughing or drilling it into the soil.
2. Ring method (placing it round the plant) and covering it with soil.
3. Side dressing and covering, or broadcasting it evenly over the field.

Specimens: B (SAND), C (CLAY), D (LOAM), O (WATER)

(a)(i) Physical properties of the dry specimens

(a)(ii) After adding water (specimen O) and mixing

(b) Specimen of greater value to farmers: D (LOAM)

Two reasons:

1. It has a good balance of sand, silt and clay, giving it good water-holding capacity together with good drainage and aeration.
2. It is rich in humus and plant nutrients and is easy to work, so it supports most crops well.

(c) Three ways of improving each of the other two specimens

Sand (B):

1. Add organic manure or compost to improve water and nutrient retention.
2. Add clay and apply mulch to reduce water loss.
3. Practise cover cropping and grow leguminous crops to build up humus.

Clay (C):

1. Add coarse sand and organic matter to improve aeration and drainage.
2. Apply lime to improve its structure (flocculation) and reduce stickiness.
3. Provide good drainage channels and practise deep ploughing to loosen it.

Specimens: G (BONE), P (DRIED ANIMAL BLOOD), T (FISH)

(a) Main nutrient(s) obtainable

• G (Bone): mineral (calcium and phosphorus).
• P (Dried animal blood): protein.
• T (Fish): protein and mineral (calcium/phosphorus); also oil/fat.

(The two main nutrients from T are protein and minerals.)

(b) Three functions of each of the two main nutrients from T

Protein:

1. Builds new body tissues for growth.
2. Repairs worn-out tissues in the body.
3. Forms enzymes, hormones and antibodies, and is used for egg/milk formation.

Minerals (calcium and phosphorus):

1. Form and strengthen bones and teeth (and egg shells in poultry).
2. Aid blood formation and clotting and muscle/nerve function.
3. Help in metabolic processes and maintain the body's acid-base balance.

(c) One feed ingredient prepared from each specimen

• G (Bone): bone meal.
• P (Dried animal blood): blood meal.
• T (Fish): fish meal.

(d) Two disadvantages of using blood meal (from P) in compounding livestock feed

1. It is unpalatable and has a strong odour, so animals may reject feed containing much of it.
2. It is deficient in some amino acids and can easily spoil or become rancid, and may spread disease if not properly processed.

Specimens: F (HOE), H (RAKE), K (PLIERS)

F (HOE)

Three functions:

1. Used for tilling/loosening the soil for planting.
2. Used for weeding and clearing between crops.
3. Used for making ridges, heaps and seed beds.

Two methods of maintenance:

1. Clean off soil and wash after use, then dry to prevent rusting; oil the metal part.
2. Sharpen the blade regularly and keep the handle firm; store in a dry place.

H (RAKE)

Three functions:

1. Used for gathering weeds, dry leaves and refuse on the farm.
2. Used for levelling the soil surface and seed beds.
3. Used for covering broadcast seeds lightly with soil and loosening the surface.

Two methods of maintenance:

1. Clean off soil and debris after use, dry the metal head and oil it to prevent rust.
2. Tighten and repair any loose teeth or handle, and store in a dry shed.

K (PLIERS)

Three functions:

1. Used for gripping and holding objects firmly.
2. Used for cutting and twisting wires (for example in fencing).
3. Used for pulling out or fixing nails and staples.

Two methods of maintenance:

1. Clean and wipe dry after use, and oil the joint/pivot to keep it moving freely and rust-free.
2. Keep the jaws and cutting edges sharp and store in a dry tool box.