WAEC SSCE - Agricultural Science - 2016 (Essay)

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This question tests knowledge of agricultural extension communication channels, the value of teaching farmers in organised groups, one of the recognised functions performed in agricultural marketing, and the identification and control of two important field-crop diseases. Each part is answered directly below.

(a) Three print and three electronic media for disseminating extension messages

Print media carry the message in a written or drawn form that the reader sees on paper:

• Newspapers
• Agricultural magazines, journals or bulletins
• Posters, leaflets, handbills or pamphlets

Electronic media carry the message as sound or moving pictures through electronic devices:

• Radio broadcasts
• Television programmes
• Mobile phone or internet services (including films and video shown on projectors or screens)

(b) Four advantages of the group method of agricultural extension

1. It reaches many farmers at the same time, so the agent's time, effort and money are used economically.
2. Farmers learn from one another, exchanging ideas, questions and practical experience during the session.
3. Peer influence and group discussion build confidence and speed up the adoption of new practices, because a farmer is more willing to try an innovation that fellow farmers accept.
4. Fewer extension agents are needed to cover a large number of farmers, easing the shortage of trained personnel.

(c) Assembling as a marketing function

Assembling is the marketing function of collecting the small quantities of produce that individual farmers grow in many scattered locations and bringing them together into large, economic lots at a central point such as an assembly market or collection depot. This bulking makes later marketing functions such as grading, storage, transport in full loads and sale to wholesalers cheaper and easier than dealing with each farmer's tiny quantity separately.

(d) Symptoms and control measures of the two crop diseases

Examination note: In part (a) keep print and electronic media strictly separate, a poster is print while a film shown on a screen is electronic. In part (d) always name a visible symptom, not the pathogen, and pair vector control (spraying the insect that carries the virus) with sanitation (removing infected plants), because both viral diseases here are insect-transmitted.

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(a) Three systems of mating in livestock management

Stud (hand) mating: A proven sire is kept in a stud, and each dam that comes on heat is brought to him for a controlled, supervised service; the dam is then taken away. The farmer decides exactly which male serves which female, so parentage and records are accurate.

Pen mating: One selected male is placed in a pen together with a group of females that are on heat, and he is allowed to serve them freely within that pen. It is easier to manage than hand mating while still keeping the sire known.

Flock (pasture) mating: Both the sires and the dams are turned out together on the range or pasture and allowed to move about and mate freely at will. It needs little labour, but the exact parentage of the offspring is uncertain.

(b) Labelled digestive tract of a hen

Food passes through the alimentary canal of the hen in the following order:

beak (mouth) → oesophagus → crop → proventriculus (true stomach) → gizzard → small intestine (duodenum and ileum) → caeca → large intestine (rectum) → cloaca → vent.

The liver, gall bladder and pancreas are associated glands that pour their secretions into the small intestine to aid digestion. The diagram below shows these parts fully labelled and in their correct order.

(c) Five reasons why ornamental plants are important

1. They beautify the environment - homes, offices, gardens and roadsides - and are widely used in landscaping.
2. They are a source of income and employment through the florist and horticultural trade (sale of flowers, bouquets, wreaths and potted plants).
3. They are used to demarcate boundaries and, when planted as hedges, serve as windbreaks and shelter belts.
4. They provide shade, help purify the air and reduce noise pollution around buildings and roads.
5. They have educational, recreational and medicinal value, and some promote tourism and earn foreign exchange for the country.

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(a) Staking in yam cultivation

Staking is the practice of providing stakes or poles to which the growing yam vines are tied so that they can climb and spread. This exposes the leaves fully to sunlight for efficient photosynthesis, which leads to bigger tubers and higher yield.

(b) Nursery practices in cocoa cultivation

1. Prepare a nursery site near a source of water and provide overhead shade.
2. Fill polythene bags with fertile topsoil.
3. Select viable, pre-germinated seeds and sow one seed per bag.
4. Water the seedlings regularly and keep the nursery weed-free.
5. Apply manure or fertilizer and control pests and diseases.
6. Harden off the seedlings by gradually removing the shade before transplanting after about four to six months.

(c) Five reasons for parboiling paddy rice

1. It makes milling easier and reduces breakage of the grains.
2. It hardens the grain.
3. It loosens the husk from the grain.
4. It improves the nutritional (vitamin) content of the milled rice.
5. It improves the keeping or storage quality and kills insects and micro-organisms.

(d) Taungya farming: three advantages and two disadvantages

Advantages:

1. Farmers grow food crops among the young forest trees, making full use of the land.
2. It provides food and income to the farmers.
3. It reduces the cost of establishing the forest because farmers weed and tend the tree seedlings.

Disadvantages:

1. The food crops compete with the tree seedlings for nutrients, water and light.
2. Farming operations may damage the tree seedlings and expose the soil to erosion.

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(a) Farm surveying

Farm surveying is the process of measuring and mapping out the boundaries, dimensions, area, shape and relative position of a piece of farmland.

(b) Four disadvantages of electrical power

1. It cannot be easily stored in large quantities.
2. It is dangerous and can cause electric shock, electrocution or fire.
3. Its installation is costly.
4. Supply is often irregular and it is not available in many remote rural areas.

(c) Four reasons why farm machines should be maintained

1. To prolong their lifespan and durability.
2. To ensure efficient performance and reduce breakdowns.
3. To reduce the cost of major repairs.
4. To prevent accidents and ensure the safety of the operator.

(d) Land as used in agriculture

Land is the natural or physical resource, including the soil and all the free gifts of nature on and under the surface, that is used for agricultural production. It is a factor of production provided by nature.

(e) How the factors affect land availability for agriculture

• (i) Population pressure: A high population increases the demand for land for houses, roads and settlement, leaving less land for farming and leading to fragmentation and over-cultivation.
• (ii) Mining: Mining takes over and destroys large areas of land and degrades the soil, so that such land can no longer be used for crop or animal production.
• (iii) Topography: Rugged, hilly, steep or waterlogged land is unsuitable for farming, so only the gentle or flat land is easily available for cultivation.

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(a) Agricultural insurance

Agricultural insurance is a contract in which a farmer pays a regular sum of money called a premium to an insurance company, and in return the company agrees to compensate the farmer against losses arising from stated risks such as fire, flood, drought, pest and disease outbreak or death of animals. It spreads the risk of farming so that a single disaster does not ruin the farmer.

(b) Types of insurance policies

1. Specific enterprise insurance: covers only a particular named farm enterprise, for example a poultry unit, a fish pond or a cocoa plantation. The farmer is compensated only for losses affecting that stated enterprise.
2. Fire disaster insurance: protects the farmer against losses caused by outbreak of fire that may destroy farm buildings, stored produce, machinery or standing crops. The company pays the agreed value of the property destroyed by fire.
3. Life assurance: covers the life of the farmer or key farm worker. On the death of the assured person, or on reaching an agreed age, the insurance company pays the agreed sum to the beneficiaries or to the assured.

(c) Process of egg formation in a hen

1. The ovary releases a mature ovum (yolk) into the funnel-shaped infundibulum, where fertilisation takes place if sperm are present.
2. The yolk moves into the magnum, where the thick albumen (egg white) is added over several hours.
3. It then passes into the isthmus, where the two shell membranes are formed around the albumen.
4. In the uterus (shell gland) water and mineral salts are added and the hard, calcareous egg shell together with its shell pigment is deposited; this is the longest stage.
5. Finally the completed egg passes through the vagina and cloaca and is laid through the vent, usually blunt end first.

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(a) Five differences between subsistence and commercial agriculture

(b) Two solutions to each problem

(i) Inadequate land

1. Introduce land reform and land-use laws to make land available.
2. Discourage fragmentation by consolidating small holdings, and practise intensive farming.

(ii) Inadequate finance

1. Provide agricultural credit and loans through banks.
2. Give government subsidies and encourage cooperative societies to pool funds.

(iii) Incidence of diseases

1. Use disease-resistant crop varieties and animal breeds.
2. Carry out regular spraying and vaccination and establish quarantine.

(c) Agricultural ecology

Agricultural ecology is the study of the relationship or interaction between crops and farm animals and their environment (both the living and the non-living components).

(d) Five sources of pollution of agricultural lands and fish ponds

1. Industrial waste and effluents.
2. Oil spillage.
3. Agrochemicals (pesticides and herbicides).
4. Excess inorganic fertilizers washed into water.
5. Sewage and domestic refuse.