WAEC SSCE - Agricultural Science - 2017 (Essay)

(a) Economic concepts:

• (i) Scarcity: Scarcity means that the resources (land, labour, capital) available to satisfy people's wants are limited relative to the unlimited wants. Because resources are limited, choices must be made.
• (ii) Scale of preference: A scale of preference is a list of a person's wants arranged in order of their importance, with the most pressing want at the top, so that the most urgent needs are satisfied first with the limited resources.

(b) Four reasons why agricultural insurance is important:

• It pays compensation to the farmer for losses from fire, flood, drought, pests or disease.
• It gives the farmer confidence to invest and expand the farm.
• It makes it easier for the farmer to obtain loans, since the insured farm is used as security.
• It spreads/reduces the risk of farming and keeps the farmer in business after a disaster.

(c) Five fishery regulations in West Africa:

• Use of nets with the approved (large) mesh size to protect young fish.
• Ban on the use of poisons, chemicals and explosives in fishing.
• Closed seasons during which fishing is prohibited to allow fish to breed.
• Licensing/registration of fishermen and fishing boats.
• Prohibition of catching immature/undersized fish and fishing in restricted zones.

(d) Five reasons why beekeeping is important:

• It produces honey used as food and medicine.
• It produces beeswax used in industry (candles, cosmetics, polishes).
• Bees pollinate crops and so increase crop yield.
• It provides income and employment to farmers.
• It requires little land and capital to start.

(a) Maize smut disease:

• (i) Causal organism: A fungus, Ustilago maydis (also called Ustilago zeae).
• (ii) Mode of transmission: By wind-borne spores (teliospores) and by soil, infected seeds and crop residues carrying the spores from one plant/season to another.
• (iii) Two symptoms:
  • Large greyish-white galls/swellings (boils) on the cob, tassel, leaves and stem.
  • The galls later burst to release a mass of black, powdery spores, and infected plants become stunted with distorted grains.
• (iv) Two cultural control measures:
  • Practise crop rotation and plant certified, disease-free seeds/resistant varieties.
  • Remove and burn infected plants (galls) and practise good field sanitation.

(b) Four forest management practices in West Africa:

• Afforestation and reforestation (planting of trees).
• Selective/controlled felling of mature trees only.
• Establishment and protection of forest reserves.
• Prevention and control of bush fires, pests and diseases.

(c)(i) Four classes of farm animals based on their uses and (ii) an example of each:

(a) Five non-government agricultural organizations in West Africa:

• West Africa Rice Development Agency (WARDA/AfricaRice)
• International Institute of Tropical Agriculture (IITA)
• Food and Agriculture Organization (FAO)
• Sasakawa Global 2000
• International Fund for Agricultural Development (IFAD)

(b) Four ways in which agriculture and industry are interrelated:

• Agriculture supplies raw materials (cotton, cocoa, oil palm, rubber) to industries for processing.
• Industry supplies farm inputs (fertilisers, machines, chemicals) to agriculture.
• Agriculture provides food for industrial workers.
• Both provide market for each other's products and provide employment and income.

(c) One function of each part of a disc plough:

(d) Four disadvantages of animal power:

• Animals are slow and cover only a small area of land per day.
• They tire easily and cannot work for long hours.
• They need feeding, housing and veterinary care, which cost money and time.
• They can be affected by diseases and may die, and cannot be used on all types of land.

(a) Five factors to consider in choosing an irrigation system in West Africa:

• The source and availability of water (rivers, dams, boreholes).
• The topography (slope and nature) of the land.
• The type of soil and its infiltration/drainage.
• The type of crop to be grown and its water requirement.
• The cost of installation and the capital available to the farmer.

(b) Four problems associated with irrigation in West Africa:

• High cost of installing and maintaining the system.
• Salinization/salt build-up and water-logging of the soil.
• Inadequate/irregular water supply and silting of channels.
• Spread of water-borne diseases such as bilharzia and pests/weeds.

(c) Area of the farmland in hectares:

Convert the length to metres: \(0.4\ \text{km} = 0.4 \times 1000 = 400\ \text{m}\).

\[ \text{Area} = \text{length} \times \text{breadth} = 400\ \text{m} \times 2400\ \text{m} = 960{,}000\ \text{m}^2 \]

Since \(1\ \text{hectare} = 10{,}000\ \text{m}^2\):

\[ \text{Area} = \frac{960{,}000}{10{,}000} = 96\ \text{hectares} \]

(d) Tillage implements:

• One primary tillage implement: Plough (disc or mould-board plough).
• Three secondary tillage implements: Harrow, ridger and cultivator.

(a) Anthrax disease:

• (i) Causal organism: A bacterium, Bacillus anthracis.
• (ii) Mode of transmission: By ingestion of feed, water or pasture contaminated with the spores; through contact with infected animals, their carcasses or products; and through wounds and biting insects.
• (iii) Two symptoms:
  • Sudden death, often with high fever before death.
  • Discharge of dark, tarry, unclotted blood from natural body openings (nose, mouth, anus) and swellings on the body.
• (iv) Two prevention and control measures:
  • Vaccinate healthy animals regularly against anthrax.
  • Burn or bury deeply (with quicklime) the carcasses of infected animals; never open them, and isolate/quarantine affected herds.

(b)(i) Four sources of plant protein in livestock feeds:

• Groundnut cake
• Soya bean meal
• Palm kernel cake
• Cottonseed cake (or brewer's dried grain)

(b)(ii) Three examples of forage legumes in West African rangelands:

• Centrosema (Centrosema pubescens)
• Stylosanthes (Stylosanthes gracilis)
• Pueraria (Pueraria phaseoloides)

(c) Five characteristics of labour as a factor of agricultural production:

• Labour is human effort (physical and mental) used in production.
• Labour cannot be separated from the labourer.
• Labour is perishable; time lost when a worker is idle cannot be recovered.
• Labour is mobile; it can move from one place or job to another.
• Labour has feelings and needs rewards (wages), rest and good treatment to work well; its supply and efficiency vary.