WAEC SSCE - Agricultural Science - 2003 (Essay)

Maelezo ya Majibu

(a) Life cycle of the bean beetle (bean weevil, Callosobruchus maculatus)

1. The adult female lays her eggs on the surface of the bean seeds, either on the field or in store.
2. Each egg hatches into a larva (grub).
3. The larva bores into the bean seed and feeds on the cotyledons inside.
4. Within the seed the larva grows and then changes into a pupa.
5. The pupa develops into an adult beetle.
6. The adult bores its way out of the seed, mates and the female lays eggs again, so the cycle repeats. (Egg to adult in about three to four weeks.)

(b)(i) Four damages done by cotton stainer to cotton plants on the field

1. It pierces and sucks sap from the bolls, buds and young shoots, weakening the plant.
2. It stains the cotton lint yellow or brown, lowering its quality and market value.
3. It introduces fungi and bacteria into the bolls, causing internal boll rot.
4. It causes premature dropping of buds and immature bolls, reducing yield.

(b)(ii) Four alternate hosts of cotton stainer

1. Okra
2. Hibiscus (roselle/soborodo)
3. Baobab
4. Kola (and other Malvaceae plants)

Maelezo ya Majibu

(a) Three factors of production in agriculture

1. Land: the natural resource on which farming takes place. It provides the soil, water and space for crops and livestock, and its reward is rent. Its supply is fixed and its quality varies from place to place.
2. Labour: the human effort, both physical and mental, applied to production, such as clearing, planting, weeding and management. Its reward is wages/salary. Labour may be skilled or unskilled, family or hired.
3. Capital: all man-made assets used to aid production, such as tools, machines, farm buildings, seeds, fertilisers and money. Its reward is interest. Capital increases the efficiency and output of the farm.

(A fourth factor, management (entrepreneur), which organises the other three and whose reward is profit, is also accepted.)

(b) Four functions of a farm manager

1. Planning the farm operations and deciding what, when and how to produce.
2. Organising and coordinating the land, labour and capital of the farm.
3. Directing and supervising farm workers and operations.
4. Keeping farm records and marketing the farm produce (and controlling finances).

Maelezo ya Majibu

(a) Six sources of farm power

1. Human (manual) power
2. Animal (draught) power
3. Mechanical power (tractors, engines, machines)
4. Electrical power
5. Wind power
6. Solar power (and water power is also acceptable)

(b) How five of the sources are utilised on the farm

• Human power: supplies the muscular energy used for operations such as clearing, hoeing, planting, weeding, harvesting and carrying loads with simple hand tools.
• Animal power: draught animals such as oxen, horses and donkeys are yoked to ploughs, harrows and carts to till the soil and to transport farm produce.
• Mechanical power: tractors and engines drive ploughs, harrows, planters, sprayers, harvesters and pumping machines, doing heavy field work quickly.
• Electrical power: runs pumping machines for irrigation, lighting in poultry houses, incubators, grinding and processing machines and refrigeration for storing produce.
• Solar power: provides heat for drying grains and crops, warms brooding houses and, through solar panels, generates electricity for farm use.

(c) Two disadvantages each of any four sources

Source	Disadvantages
Human power	(i) Generates very little power, so work is slow. (ii) Cannot cover large areas and tires quickly.
Animal power	(i) Animals fall sick, tire and cannot work all day. (ii) Cannot work on rocky or heavy soils and need feeding and care.
Mechanical power	(i) High cost of purchase, fuel and maintenance. (ii) Requires skilled operators and causes soil compaction.
Wind power	(i) Unreliable because it depends on the presence of wind. (ii) Equipment is costly to install and only supplies small power.

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(a) Four factors to consider when siting a fish pond

1. Adequate and reliable source of clean water.
2. Suitable soil that can hold water (clayey/loamy soil with good water retention).
3. Gentle slope of the land to allow easy filling and draining of the pond.
4. Nearness to market, road and source of feed, and freedom from flooding or pollution.

(b) Six ways of maintaining a fish pond

• Regular feeding: supply supplementary feed at correct times and amounts for good growth.
• Liming and fertilising: apply lime to correct acidity and fertiliser/manure to promote natural food (plankton).
• Control of water level and quality: maintain the correct depth and change or aerate water to keep oxygen adequate.
• Removal of predators and weeds: clear aquatic weeds and eliminate snakes, birds and predatory fish.
• Control of pests and diseases: observe the fish regularly and treat or isolate diseased stock.
• Repair of pond structures: check and mend the dykes, inlets, outlets and screens to prevent leakage and escape of fish.

Rinderpest and Newcastle disease

Heading	Rinderpest	Newcastle disease
(i) Host organism	Cattle (and other ruminants such as sheep and goats)	Poultry (fowls, especially chickens and turkeys)
(ii) Causal organism	A virus (rinderpest virus)	A virus (Newcastle disease virus)
(iii) Mode of transmission	Direct contact with infected animals; through contaminated feed, water, saliva, faeces and discharges	Direct contact with infected birds; through contaminated feed, water, droppings, droplets and equipment
(iv) Symptoms	High fever, loss of appetite, discharge from eyes and nose, mouth ulcers, severe diarrhoea, dehydration and death	Difficult breathing, gasping, coughing, greenish diarrhoea, twisting of the neck (torticollis), paralysis, drop in egg laying and death
(v) Control	Vaccination, quarantine of new/infected stock, slaughter of infected animals, good sanitation	Vaccination, isolation of sick birds, proper sanitation and disinfection, destruction of dead birds

Maelezo ya Majibu

(a) What is land?

Land is the natural, immovable portion of the earth's surface, together with all the free gifts of nature on and beneath it (soil, water, minerals, vegetation and air), which man uses for agricultural and other productive purposes.

(b) Six uses of land

1. Cultivation of crops (arable and plantation farming).
2. Rearing of livestock and establishment of pastures.
3. Construction of farm buildings, houses and roads.
4. Forestry and establishment of plantations.
5. Fish farming and construction of dams or reservoirs.
6. Mining and quarrying of minerals.

(c) Four ways an agricultural land may appreciate in value

1. Construction of good access roads and provision of infrastructure near the land.
2. Improvement of soil fertility through manuring, liming and good management.
3. Provision of irrigation, drainage or water supply on the land.
4. Development of the land with buildings, fencing and permanent tree crops, or increased demand as the population around it grows.

(d) Five benefits derived from soil organisms in agriculture

1. They decompose organic matter and release nutrients into the soil.
2. They aid in the formation of humus, improving soil structure and fertility.
3. Some (for example Rhizobium) fix atmospheric nitrogen for plant use.
4. They improve soil aeration and drainage by burrowing and mixing the soil.
5. They help in nutrient cycling and in breaking down toxic substances, keeping the soil healthy.

Maelezo ya Majibu

(a) Four marketing agents

1. Wholesalers
2. Retailers
3. Commission agents/brokers
4. Middlemen (assemblers)

(b)(i) Four characteristic features of co-operative societies

1. Voluntary and open membership.
2. Democratic control (one member, one vote).
3. Members contribute capital through shares and share profits/dividends.
4. Formed to promote the common economic interest of members, with limited interest on capital.

(b)(ii) Four advantages of co-operative societies in agriculture

1. They provide credit/loans to members at low interest.
2. They enable members to buy farm inputs in bulk at cheaper rates.
3. They provide a better and larger market for members' produce, ensuring fair prices.
4. They give members access to storage, processing facilities and useful farming information.

(c)(i) Three merits of individual (personal) contact in extension method

1. It allows the farmer's specific problems to be identified and solved directly.
2. It builds trust and a good relationship between the farmer and the extension agent.
3. It is effective in persuading the farmer to adopt new practices.

(c)(ii) Three Agricultural Extension Programmes (in Nigeria)

1. Agricultural Development Projects (ADPs).
2. National Agricultural Extension and Research Liaison Services (NAERLS).
3. Training and Visit (T&V) extension system (and Farmer Field Schools).

Maelezo ya Majibu

Reading the plan. The farm is a trapezium with the two parallel boundaries measuring 70 m (top, BC) and 90 m (bottom, AD), and the perpendicular distance between them AB = 45 m.

(a) Area of the land in hectares

\[ \text{Area} = \tfrac{1}{2}(BC + AD)\times AB = \tfrac{1}{2}(70 + 90)\times 45 \] \[ = \tfrac{1}{2}\times 160 \times 45 = 80 \times 45 = 3600\ \text{m}^2 \]

Converting to hectares, using \(1\ \text{hectare} = 10\,000\ \text{m}^2\):

\[ \text{Area} = \frac{3600}{10\,000} = 0.36\ \text{hectares} \]

(b) Number of planting materials required

Step 1: Share the land between the crops.

\[ \text{Plantain area} = \frac{80}{100}\times 3600 = 2880\ \text{m}^2 \] \[ \text{Pineapple area} = \frac{20}{100}\times 3600 = 720\ \text{m}^2 \]

Step 2: Ground area occupied by one plant.

\[ \text{Plantain: } 4\ \text{m} \times 4\ \text{m} = 16\ \text{m}^2 \] \[ \text{Pineapple: } 2\ \text{m} \times 2.5\ \text{m} = 5\ \text{m}^2 \]

Step 3: Number of plants = crop area ÷ area per plant.

\[ \text{Plantain} = \frac{2880}{16} = 180\ \text{stands} \] \[ \text{Pineapple} = \frac{720}{5} = 144\ \text{stands} \]

Crop	Area (m2)	Spacing	m2 per plant	Plants
Plantain	2880	4 m x 4 m	16	180
Pineapple	720	2 m x 2.5 m	5	144

The farm requires 180 plantain suckers and 144 pineapple suckers.

Maelezo ya Majibu

Rinderpest and Newcastle disease

Heading	Rinderpest	Newcastle disease
(i) Host organism	Cattle (and other ruminants such as sheep and goats)	Poultry (fowls, especially chickens and turkeys)
(ii) Causal organism	A virus (rinderpest virus)	A virus (Newcastle disease virus)
(iii) Mode of transmission	Direct contact with infected animals; through contaminated feed, water, saliva, faeces, urine and nasal/eye discharges	Direct contact with infected birds; through contaminated feed, water, droppings, air-borne droplets, equipment and handlers
(iv) Symptoms	High fever, loss of appetite, watery discharge from eyes and nose, ulcers in the mouth, severe (blood-stained) diarrhoea, dehydration, emaciation and death	Difficult breathing, gasping and coughing, greenish watery diarrhoea, twisting of the neck (torticollis), paralysis of legs and wings, drop in egg production and death
(v) Control	Vaccination of healthy stock, quarantine of new/infected animals, slaughter of infected animals, good hygiene and sanitation	Vaccination of birds, isolation of sick birds, proper sanitation and disinfection, and destruction/burial of dead birds

Maelezo ya Majibu

(a) Three ways each factor affects agricultural development

(i) Poor tools and implements

• They lower productivity because only small areas can be cultivated with crude hand tools.
• They cause drudgery and make farm work slow and tiring, discouraging the youth from farming.
• They lead to poor quality of farm operations and waste of time and energy, keeping output at subsistence level.

(ii) Poor storage facilities

• They cause heavy post-harvest losses through spoilage of produce.
• They expose produce to attack by pests and rodents, reducing quality.
• They force farmers into distress sales at low prices soon after harvest, reducing income and causing food scarcity later.

(b) One solution to the problem of poor tools and implements

Provide improved and modern farm machinery and implements to farmers at subsidized prices (mechanization), supported by training and credit facilities.

(c) Three objectives each

(i) Land Use Act

• To make land easily available and accessible for agricultural and other development.
• To ensure fair and equitable distribution of land among citizens.
• To control land speculation and reduce land disputes and litigation.

(ii) Quarantine programme

• To prevent the introduction and spread of pests and diseases from one place to another.
• To inspect and certify imported and exported plants and animals.
• To isolate, treat or destroy infected plants and animals so as to protect local agriculture.

(iii) Government agricultural loan and subsidy schemes

• To provide farmers with credit and finance for production.
• To reduce the cost of farm inputs through subsidy so that more farmers can afford them.
• To encourage increased production, mechanization and the entry of new farmers into agriculture.

Maelezo ya Majibu

(a) Four functions of each macro-nutrient in plant nutrition

(i) Nitrogen

1. Promotes vegetative growth and the development of leaves and stems.
2. Forms an essential part of proteins, enzymes and protoplasm.
3. Is a constituent of chlorophyll, giving leaves their green colour.
4. Improves the quality and yield of leafy crops.

(ii) Phosphorus

1. Promotes healthy root development and establishment of seedlings.
2. Aids flowering, fruiting and seed formation, hastening crop maturity.
3. Is involved in energy transfer within the plant (as part of ATP).
4. Strengthens the plant and improves resistance to disease and lodging.

(iii) Potassium

1. Strengthens stems and straw, reducing lodging.
2. Aids the formation, movement and storage of carbohydrates and sugars.
3. Improves resistance to diseases and to drought.
4. Regulates the opening and closing of stomata and the water balance of the plant.

(b) Four factors that affect the availability of nutrients to crops

1. Soil pH (acidity or alkalinity).
2. Soil moisture content.
3. Soil temperature.
4. Presence of soil organic matter and micro-organisms (and soil texture/aeration).