WAEC Agricultural Science 1988 past questions and answers

A lease lets the farmer use land for an agreed period in return for rent; the owner keeps ownership.

Free use and control of inherited land is an advantage of inheritance, not a problem; the others are its usual drawbacks.

Texture is about the proportions of particle sizes (sand, silt, clay); arrangement of particles is structure.

Repeated expansion on heating and contraction on cooling cracks rocks into fragments (physical weathering).

Biotic factors are living things; a parasite is living, the others are non-living (abiotic) factors.

Granite forms when molten magma cools and solidifies, so it is an igneous rock.

The A-horizon (topsoil) holds most organic matter, roots and soil organisms.

Nitrogen deficiency shows first on older leaves as yellowing and then browning that starts at the tip and moves back along the midrib (a V shape in maize). Phosphorus deficiency gives dark green or purplish leaves instead.

A mulch covers the soil, shading it and cutting down evaporation of soil water.

Sand particles are 0.02–2.0 mm across; silt and clay are finer and gravel is coarser.

Nitrogen promotes leafy vegetative growth, which is what leafy vegetables are grown for.

Earthworm burrows and casts loosen and aerate the soil and bind particles into crumbs, improving structure.

Igneous rocks form when molten magma cools and hardens.

Rhizobium in legume root nodules gets food from the plant and fixes nitrogen for it, so both benefit (symbiosis).

Energy from the sun is called solar energy.

After clearing, the first tillage operation is ploughing; harrowing and ridging come after it.

Oil and grease keep air and moisture off metal; water causes rusting.

A spade is a digging tool, not a surveying instrument.

Moulds are fungi that grow on damp stored grain; the other diseases attack growing plants.

A garden is a small, intensively cultivated plot for vegetables.

Stylo (Stylosanthes) is a forage legume, not a grass.

Planting trees renews (regenerates) the forest.

Mulching conserves soil moisture and controls weeds; it is not a pest-control method.

There is no chemical cure for plant viruses, so growing resistant varieties is the surest prevention.

Removing excess seedlings to leave the right number per stand is thinning.

Hay is made by cutting the forage, drying it in the sun and then baling it.

Cutting only chosen (specified) trees is selective exploitation.

Maize rust is caused by the fungus Puccinia.

Sex (reproductive) cells are gametes; they fuse to form a zygote.

Okra is a dry fruit that splits along several lines when ripe, which makes it a capsule.

Birds such as weaver birds and quelea feed on cereal grains like rice, sorghum and millet.

In controlled pollination, man transfers selected pollen by hand to make chosen crosses.

Ginning separates the cotton lint (fibre) from the seeds.

Groundnut rosette virus is carried from plant to plant by aphids.

Poultry have two caeca; the mammals listed have a single caecum.

The tapeworm's head, which carries the hooks and suckers, is the scolex.

Rumen microbes digest cellulose, make microbial protein and B vitamins and produce gas; belching the gas out (eructation) is done by the animal.

Eggs hatch without light; temperature, humidity, ventilation and turning are essential.

Kuri cattle are found around Lake Chad in Borno.

Layers need extra calcium and phosphorus for eggshells, supplied by bone meal.

Forage crops are grown mainly to feed livestock.

Anthrax is caused by a bacterium (Bacillus anthracis); the others are viral.

Fingerlings are young fish, about the size of a finger.

Progeny testing judges a parent by how well its offspring perform.

Brucellosis (contagious abortion) is known mainly for causing abortion in cows.

Heat signs include mounting, restlessness, noise and mucus from the vulva, not from the rectum.

Pigs have no horns, so dehorning is never done.

Bulky, high-fibre feeds are roughages; concentrates are low in fibre.

Newcastle disease attacks the respiratory and nervous systems, causing gasping and paralysis.

Fish is commonly preserved by salting and smoking, which remove moisture and stop decay.

Turkey eggs take about 28 days to hatch, so 27 days is the closest option (21 days is for chickens).

Groundnut cake is a protein-rich oilseed by-product; the others mainly supply energy.

Liver flukes are flat, leaf-shaped brownish worms living in the liver and bile ducts.

A new farmer should start with what he knows well; spreading into many enterprises at once spreads scarce resources too thin.

Extension workers carry research findings and new knowledge to farmers.

Mortgage banks lend mainly for housing, not farming.

Sales happen after production; they do not change how efficiently crops and animals are produced.

Without storage facilities, farmers are forced to sell soon after harvest, even at low prices.

Farmers adopt a new practice best when they see it work in a demonstration.

Any eight, each named and briefly explained:
Land tenure/land shortage: fragmented holdings and insecure ownership prevent large farms
Lack of finance/credit: farmers lack collateral and interest rates are high
Inadequate or costly farm inputs: improved seeds, fertilizers, agrochemicals are scarce or late
Poor storage and processing facilities: heavy post-harvest losses
Poor transport and road network: produce cannot reach markets cheaply
Poor marketing system: unstable prices, exploitation by middlemen
Illiteracy and inadequate extension services: slow adoption of new methods
Low level of mechanisation: drudgery limits the area farmed
Pests and diseases: reduce yield and quality
Lack of rural amenities: rural–urban drift reduces farm labour
Inconsistent government policies and unfavourable weather

Name the factor, then give one sentence on how it holds back large-scale farming.

(a) Mechanisation is the use of machines and power-driven implements (tractors, ploughs, harrows, planters, harvesters, processors) in place of human and animal labour on the farm
(b) Advantages: larger areas cultivated; operations done quickly and on time; reduces drudgery; higher output and efficiency; encourages large-scale/commercial farming
Disadvantages: displaces labour (unemployment); compacts and damages soil structure; high cost of machines and maintenance; pollution from fuel; may encourage erosion
(c) Any four, discussed: small and scattered holdings; high cost of machines and spare parts; lack of skilled operators and mechanics; land tenure system; unsuitable topography/tree stumps/rocky land; seasonality of farm work leaving machines idle; poor finance/credit

Give a definition, then balance advantages against disadvantages before the limitations.

(a) Bush burning: destroys organic matter and soil organisms; exposes soil to erosion; loses nitrogen and sulphur; adds potash (ash) and may raise pH; kills weed seeds and some pests
(b) Fertilizer application: adds nutrients and raises fertility and yield; excess or wrong type can make soil acidic, harm soil organisms and pollute water
(c) Grazing: dung and urine add nutrients; overgrazing removes plant cover, compacts soil by trampling and causes erosion
(d) Crop rotation: maintains fertility (legumes add nitrogen); different rooting depths use nutrients from different layers; breaks pest and disease cycles; controls weeds and erosion

For each practice give both the good and the bad effects on the soil.

(a) Any six: crop farming; grazing/livestock; forestry/forest reserves; wildlife/game reserves; residential housing; industry; roads, railways, airports; mining; recreation; schools and public institutions
(b) Any five, discussed: population pressure; land tenure system; topography (steep, swampy land); soil type/fertility; climate; government policy (e.g. Land Use Act, reserves); urbanisation and industrial use; erosion and other land degradation; economic factors such as cost of land

Uses are a simple list; factors need a short explanation each.

(a) Any ten with correct botanical names, e.g. grasses: elephant grass – Pennisetum purpureum; guinea grass – Panicum maximum; giant star grass – Cynodon plectostachyus; carpet grass – Axonopus compressus; spear grass – Imperata cylindrica; Gamba grass – Andropogon gayanus; Bahama grass – Cynodon dactylon. Legumes: centro – Centrosema pubescens; stylo – Stylosanthes gracilis; kudzu – Pueraria phaseoloides; calopo – Calopogonium mucunoides; cowpea – Vigna unguiculata
(b) Any three, discussed: rainfall (amount and distribution); temperature; soil type and fertility; topography; grazing pressure/management; pests, diseases and bush burning; light intensity

Write the common name and the two-part botanical name for each species.

Example: oil palm (Elaeis guineensis); groundnut or coconut also acceptable
(a) Rainfall about 1500–2500 mm well distributed; temperature 24–32 °C; deep, well-drained loamy soil rich in humus, pH about 4.5–6
(b) Transplant at start of rains (about March–May/June); about 140–150 seedlings per hectare; spacing about 8–9 m triangular
(c) Pre-nursery in boxes/small bags, then nursery in polythene bags; watering, shading, weeding, pest control; seedlings transplanted at about 12 months
(d) First harvest 3–5 years after planting; ripe bunches (reddish, loose fruits dropping) cut with a chisel or harvesting knife
(e) Bunches fermented, fruits stripped, boiled and pounded/pressed to extract oil, oil clarified by boiling and stored in clean airtight drums; kernels dried and cracked for palm kernel oil

Name the crop first; marks need figures (rainfall, spacing, years to harvest).

Any four:
Carbohydrates: carbon, hydrogen, oxygen; maize, cassava, guinea corn, molasses, grass; supply energy
Proteins: carbon, hydrogen, oxygen, nitrogen (some sulphur, phosphorus); fish meal, groundnut cake, soya bean meal, blood meal; growth, repair, production of eggs and milk
Fats and oils: carbon, hydrogen, oxygen; oilseeds, palm kernel cake, cotton seed; concentrated energy, body heat, carry fat-soluble vitamins
Minerals: elements such as calcium, phosphorus, sodium, iron; bone meal, oyster shell, salt lick, limestone; bones, teeth, eggshell, blood formation, body regulation
Vitamins: organic compounds (A, B, D, E, K); green forage, fish oil, premix; protect against deficiency diseases and regulate body processes
Water: hydrogen and oxygen; drinking water, succulent feed; transport of nutrients, temperature control

For each nutrient give composition, one or two sources and its main function.

(a) Ovary releases the yolk (ovum) into the infundibulum, where fertilisation takes place (about 15–30 minutes)
Magnum: thick albumen (egg white) added (about 3 hours)
Isthmus: inner and outer shell membranes added and egg shaped (about 1¼ hours)
Uterus (shell gland): thin albumen and water added, shell and pigment laid down (about 19–20 hours)
Vagina/cloaca: egg passes out and is laid; whole process about 24–26 hours
(b) Any six: oestrogen brings on heat and female secondary sex characters; progesterone prepares the uterus and maintains pregnancy; testosterone/androgen develops male characters and sperm production; FSH stimulates follicle growth/sperm formation; LH causes ovulation; oxytocin causes uterine contraction at birth and milk let-down; prolactin starts milk secretion

Follow the egg down the oviduct in order, naming what each part adds.

(a) Land: all natural resources (soil, water, minerals) used in farming; reward is rent
Labour: human effort, physical or mental, family or hired; reward is wages
Capital: man-made assets used in production – tools, machines, buildings, money; reward is interest
Management/entrepreneur: organises the other factors and bears the risk; reward is profit
(b) Any four: planning; organising; decision making; coordinating/supervising; record keeping; marketing produce; controlling/evaluating; staffing

Each factor needs a meaning and an example; functions can be listed.

(a) Marketing/commodity boards: government bodies that buy export crops (cocoa, palm produce, groundnut), fix prices, grade and control quality, store and export produce, stabilise farmers' income
(b) Co-operative societies: farmers pool resources to buy inputs and sell produce in bulk, get better prices, give credit and education to members
(c) Middlemen/wholesalers: buy in bulk from farmers, store, grade, transport and sell to retailers or processors; bridge producer and consumer but may raise prices and exploit farmers
(d) Producers: farmers who grow the produce; may sell directly at farm gate or local markets, prepare produce (clean, grade) for sale

Say what each does in the marketing chain and how it helps or affects the farmer.