WAEC SSCE - Agricultural Science - 2014 (Essay)

Answer Details

(a) Elasticity of demand

Elasticity of demand is the degree of responsiveness of the quantity of a commodity demanded to a change in one of the factors affecting demand, especially a change in its price. It is expressed as:

\[ \text{Price elasticity of demand} = \frac{\text{percentage change in quantity demanded}}{\text{percentage change in price}} \]

(b) Terms in agricultural production

• (i) Collateral: a valuable asset or property (such as land, buildings or a certificate of occupancy) that a borrower pledges to a lender as security for a loan, which the lender can take if the loan is not repaid.
• (ii) Farm inventory record: a record that shows a complete list of all the assets (property and stock) on the farm, together with their values, at a particular time.

(c) Three merits and three demerits of the retailer

Merits:

1. Sells produce in small quantities that consumers can afford.
2. Brings goods close to consumers in their localities.
3. Sometimes gives credit and useful information to consumers.

Demerits:

1. Charges higher prices, increasing the cost to the consumer.
2. Handles only small quantities, so the range of goods may be limited.
3. May sell inferior or adulterated produce and add to the number of middlemen who reduce the farmer's share.

(d) Two roles of each hormone in animal reproduction

• (i) Testosterone: (1) brings about the development of male secondary sexual characteristics; (2) stimulates the production of sperm and male sexual behaviour (libido).
• (ii) Progesterone: (1) prepares and maintains the uterus (womb) for pregnancy; (2) maintains pregnancy and prevents further ovulation, and prepares the mammary glands for milk secretion.

(e) Four ways of preserving fish

1. Smoking
2. Drying (sun-drying)
3. Salting
4. Freezing/refrigeration (canning also acceptable)

Answer Details

(a) Explanation of terms

• (i) Farmstead: the part of a farm on which the farm buildings and their immediate surroundings stand, such as the farmhouse, barns, stores, pens and yards where the day-to-day activities of the farm are based.
• (ii) Secondary tillage: the lighter cultivation operations carried out after primary tillage to break the soil into a fine tilth, level it and prepare a good seed bed (for example harrowing, ridging and levelling).

(b) One function of each part of a mouldboard plough

(c) One natural process that takes carbon away from the atmosphere

Photosynthesis: green plants absorb carbon dioxide from the atmosphere and use it, in the presence of sunlight and chlorophyll, to manufacture carbohydrates, thereby removing carbon from the air.

(d) Three ways of replenishing plant nutrients in the soil

1. Application of organic manure (farmyard manure, compost, green manure).
2. Application of inorganic (chemical) fertilisers.
3. Practising crop rotation with legumes and allowing the land to fallow.

(e) Two deficiency symptoms of calcium in crops

1. Death of the growing points (terminal buds) and poor root development.
2. Young leaves become deformed, curled or show scorching/dieback of their tips and margins.

(f) Four soil organisms

1. Earthworm
2. Termite
3. Bacteria
4. Fungi (nematodes and millipedes also acceptable)

Answer Details

(a) Commercial farming

Commercial farming is the large-scale production of crops and/or livestock mainly for sale and profit, rather than for the farmer's own consumption.

(b) Two agricultural produce used by each agro-based industry

• (i) Canning industry: tomatoes and fruits (for example pineapple/orange); fish and vegetables are also acceptable.
• (ii) Beverage industry: cocoa and coffee (also tea).
• (iii) Feed mill: maize and groundnut cake (also soya bean, fish meal, bone meal).

(c) Two aims of each organisation

(i) International Livestock Centre for Africa (ILCA):

1. To carry out research aimed at improving livestock production in Africa.
2. To train personnel and provide information for the development of the livestock industry.

(ii) International Institute for Tropical Agriculture (IITA):

1. To carry out research to improve the yield and quality of tropical food crops.
2. To develop improved crop varieties and better farming systems, and to train agricultural scientists.

(d) Surface irrigation

Surface irrigation is a method of applying water to crops by allowing it to flow over and spread across the surface of the land by gravity (for example through furrows, basins or flooding).

(e) Soil horizons

• (i) Horizon A (topsoil): the uppermost layer; it is dark in colour, rich in humus/organic matter and soil organisms, and is the most fertile layer where most plant roots grow.
• (ii) Horizon D (bedrock/parent rock, R horizon): the deepest layer consisting of solid, unweathered parent rock from which the soil above is formed.

Answer Details

(a) Five roles of agricultural extension in agricultural development in West Africa

1. Transfer of improved technology: Extension carries research findings such as improved seeds, fertilizers and better husbandry practices from research stations to the farmer.
2. Farmer education and training: It teaches farmers modern skills through demonstrations, field days and lectures, thereby raising their competence.
3. Increasing productivity and income: By promoting good practices it helps raise crop and animal yields, improving farmers' earnings and living standards.
4. Feedback link to researchers: It relays farmers' problems and needs back to research institutes so that research is made relevant to real field conditions.
5. Encouraging adoption of innovations and cooperation: It motivates farmers to form cooperatives, obtain credit and adopt new inputs, marketing and processing methods.

(b) Four problems faced by agricultural extension workers in West Africa

1. Poor transport and bad roads make it difficult to reach farmers in remote rural areas.
2. Inadequate funding for salaries, inputs and demonstration materials limits their work.
3. Illiteracy and conservatism of farmers cause resistance to new ideas.
4. Shortage of trained personnel gives too many farmers per extension worker (high farmer-to-agent ratio).

(c) Cultivation of groundnut

(i) Soil requirements: Groundnut thrives on deep, well-drained, loose sandy-loam soil that is loose enough for the pegs to penetrate; a slightly acid to neutral soil (pH about 5.5 to 6.5) rich in calcium is best. Waterlogged, heavy clay soils should be avoided.

(ii) Method of propagation: Groundnut is propagated sexually by seeds (the shelled kernels), sown directly at stake on ridges or flat beds.

(iii) Two methods of storage:

• Storage in the pod (unshelled) in well-ventilated cribs, barns or jute bags in a cool dry store.
• Storage of shelled, well-dried seeds in air-tight containers or treated bags to keep moisture and pests out.

(d) Pests of maize

Two field pests: maize stem borer and army worm (also grasshoppers, birds such as the quelea).

Two storage pests: maize weevil (Sitophilus zeamais) and the grain moth / rust-red flour beetle.

Answer Details

(a) Cultivation of cassava

• (i) Soil requirements: deep, loose, well-drained sandy-loam soil, fairly fertile and free of waterlogging.
• (ii) Spacing: about 1 m x 1 m (one metre between rows and one metre within rows).
• (iii) One disease: cassava mosaic disease.
• (iv) One pest: cassava mealybug (or grasshopper/variegated grasshopper).

(b) Difference between natural and artificial pasture

A natural pasture is grassland made up of grasses and herbs that grow on their own without being deliberately planted by man, whereas an artificial (established) pasture is one that is deliberately planted and managed by man using selected grasses and legumes.

(c) Disease as used in crop production

A disease is any abnormal condition that disturbs the normal structure or functioning of a crop plant, caused by pathogens such as fungi, bacteria and viruses or by unfavourable conditions, leading to reduced growth and yield.

(d) Mendel's law of independent assortment

It states that when two or more pairs of contrasting characters (genes) are considered together, each pair separates and is inherited independently of the others during the formation of gametes.

(e) Regeneration as a forest management practice

Regeneration is the renewal or re-establishment of a forest, either naturally (from seeds and shoots of existing trees) or artificially (by deliberately planting seedlings), to replace trees that have been removed and keep the forest productive.

(f) Five effects of deforestation

1. It leads to soil erosion.
2. It reduces soil fertility (loss of organic matter and leaching).
3. It destroys the habitat of wildlife, reducing biodiversity.
4. It reduces rainfall and alters the climate.
5. It causes desertification and loss of timber and forest products.

Answer Details

(a) Animal nutrition

Animal nutrition is the branch of animal science concerned with the intake, digestion, absorption and utilisation of food nutrients (carbohydrates, proteins, fats, vitamins, minerals and water) by farm animals for growth, maintenance, reproduction and production.

(b) Four functions of oestrogen in animal reproduction

1. It brings about the signs of heat (oestrus) and the sexual receptivity of the female.
2. It promotes the development of the female secondary sexual characteristics.
3. It stimulates growth and repair of the lining of the uterus (endometrium) in readiness for the fertilised egg.
4. It aids development of the mammary (milk) glands and the birth canal for parturition.

(c) Methods of animal improvement

(i) Selection: Choosing and keeping for breeding only those animals with the most desirable traits (high milk, fast growth, disease resistance) while culling inferior ones, so that good genes are passed to the offspring.

(ii) Breeding: Deliberate mating of selected animals to combine or fix desirable characters. It includes in-breeding, out-breeding, cross-breeding and up-grading to produce superior offspring.

(iii) Introduction: Bringing in improved breeds or stock from another area or country to replace or upgrade the local, lower-yielding animals.

(d) Ornamental plants

Ornamental plants are plants grown mainly for their beauty, that is for the decoration of homes, gardens, offices and surroundings because of their attractive flowers, leaves, form or scent, rather than for food.

(e) Four vegetative methods of propagating ornamental plants

1. Stem cuttings
2. Layering
3. Budding
4. Grafting (also division of clumps/suckers)