WAEC Agricultural Science 2010 past questions and answers

Under freehold the individual owns the land outright and can sell, lease or pass it on.

The key gives religious beliefs; ignorance, poor marketing and population size are the usual factors listed as limiting agricultural development.

Labour is supplied by the farmer and his workers, not by government.

Game reserves conserve wild animals so that species do not die out.

Disease-resistant varieties reduce losses and raise yields.

A parasite lives on or in the animal and feeds on it, lowering its productivity.

Raindrops hit bare soil and splash particles out of place: splash (raindrop) erosion.

Cotton, millet and groundnut suit the drier savanna; cocoa, kola, oil palm and rubber need the forest zone.

Metamorphism of sandstone produces quartzite.

Water breaks rocks physically (running water, freezing) and chemically (hydrolysis, solution, hydration).

Clay's pores are tiny, so air and water move through it poorly (low porosity in the sense of drainage), but water rises well by capillarity.

Maize streak is a virus disease spread by leafhoppers.

Respiration releases carbon dioxide back into the air.

Crop rotation keeps the land covered and improves soil; the others leave soil bare.

Sprinklers can water large areas, including uneven land; they are costly to install.

Most farm work is done by people, animals and machines; wind, solar and electricity are little used.

The curved mouldboard lifts and turns over the slice cut by the share.

Disease-resistant varieties come from plant breeding, not machines.

A theodolite measures both horizontal and vertical angles.

Water near the farmstead cuts costs and helps irrigation and processing; erosion of buildings is a danger, not a reason.

Harrowing, filling-in gaps (supplying) and mulching are all routine field practices in crop husbandry.

Staking spreads the leaves out to the sun, so they make more food.

In grafting a shoot (scion) of one plant is joined onto the stem and roots (stock) of a related plant.

Coconut gives copra, oil and coconut candy; jam is made from fruits.

Drilling puts fertilizer in a shallow furrow along each row, close to the roots.

Weed seeds stay alive (viable) for a long time, which helps weeds survive.

Coffee, especially Arabica, prefers the cool climate and well-drained soils of highlands.

Rotation and mixing break pest life cycles; growing one crop all the time does the opposite.

Oil palm is planted about 9 m apart in a triangle, giving about 143 palms per hectare.

Stylosanthes is a legume; the others are grasses.

Moulds are fungi that thrive on damp grain.

They have nodes and buds, which shows they are stems, not roots.

Ginning separates cotton fibre (lint) from the seeds.

The larvae live inside the stems, so infested stalks are destroyed by burning.

A resistant variety can withstand attack by disease organisms.

Butter-fat content matters in dairy cattle, not beef cattle.

Oxytocin makes the udder muscles squeeze milk out.

Microbes in the large caecum break down fibre.

Colostrum (first milk) carries antibodies from the mother.

Ewes carry their lambs for about 5 months (about 147–150 days).

A maintenance ration only keeps the animal alive at the same weight.

Cassava must be processed (peeled, soaked, dried) to remove cyanide before animals eat it.

When a cock mates a hen he treads on her back, so it is called treading.

Anthrax is caused by the bacterium Bacillus anthracis.

Tilapia lives in rivers, lakes and ponds; sardine and herring are sea fish.

Anthrax, brucellosis and trypanosomiasis can all infect humans; rinderpest cannot.

Identifying where a disease came from is part of diagnosis after an outbreak, not prevention.

Lice live on the outside of the body; the others live inside.

Manure can be brought in; water, soil and land shape decide whether a pond is possible.

Smoking dries the fish with heat and removes most of the water.

Sudden death with dark, unclotted blood from body openings is typical of anthrax.

At ₦40, supply is 110 and demand is 20, so the surplus is 110 − 20 = 90 units.

At ₦20, quantity demanded (60) equals quantity supplied (60).

Money lenders charge very high interest and demand quick repayment.

Accounts payable are debts the farm owes; the others are assets.

All three (seasonal supply, poor transport and lack of credit) hinder marketing.

Only people who can read benefit from newspapers.

(a)(i) Monoculture: the same single crop is grown on the same land year after year. Monocropping: one crop is grown on a piece of land in a season (the crop may change from season to season).
(ii) Shifting cultivation: the farmer cultivates land until it is exhausted, then abandons both the land and his settlement and moves to a new area. Land rotation: the farmer moves to new plots in turn but keeps his permanent home and returns to the first plot after a fallow.
(b) Any four: high capital needs and lack of credit; land tenure problems/fragmentation; high cost of machines, spare parts and inputs; lack of skilled manpower; poor marketing, storage and processing facilities; poor infrastructure; pests and diseases; unfavourable government policies.
(c) Any four: pulling implements such as ploughs, harrows and ridgers; transporting inputs and produce with a trailer; powering stationary machines (pumps, shellers, grinders) through the PTO; lifting implements with the hydraulic system; spraying, planting and harvesting with attached machines.
(d) Any four: clearing with cutlass/machete; felling trees with axe; burning the bush; stumping; hoeing/tilling with hoes; making mounds or ridges by hand.

Each distinction must say what is different between the two systems.

(a)(i) Education and extension teach farmers improved methods and new varieties, so they adopt modern practices and production rises; they also attract youths into farming.
(ii) Environmental degradation (erosion, deforestation, overgrazing, pollution, desertification) destroys soil fertility and farmland, so production falls.
(b) Any three: land cannot be used as collateral for loans; fragmentation into small plots; insecurity of tenure discourages permanent investment and tree crops; disputes over land; hinders mechanisation and large-scale farming.
(c) Any four: thermostat; thermometer; hygrometer/humidity tray; egg trays; heater/heat source; fan/ventilator; egg turner; counter.
(d)(i) Yam barn; (ii) airtight containers/silo/crib/rhumbu (cowpea); (iii) refrigerator/freezer/cold room for fresh fish.

Explain "how" in (a): say what each factor does to production.

(a) Chemical weathering is the breakdown of rocks by chemical reactions between the minerals and water, oxygen, carbon dioxide or acids, which changes the minerals into new substances.
(b) Any four explained: hydrolysis – water reacts with minerals such as feldspar, replacing their ions with H⁺; hydration – minerals take up water and swell (e.g. haematite to limonite) so the rock weakens; oxidation – oxygen reacts with iron minerals, forming rusty oxides; carbonation – carbonic acid (CO₂ in rain) dissolves limestone to soluble calcium bicarbonate; solution – soluble minerals (e.g. rock salt) dissolve in water; reduction – minerals lose oxygen in waterlogged soils.
(c) Any four: controls seed germination; affects root growth and nutrient uptake; affects activity of micro-organisms and rate of decomposition; affects water evaporation; affects rate of chemical reactions in soil; extremes kill seedlings.

For each process give what reacts and what is formed.

(a)(i) To find green pasture/feed; to find drinking water; (also to escape the heat and tsetse-free dry-season conditions).
(ii) Tools are cheap and affordable; farms are small and fragmented; tools are easy to use and repair without special skill; machines and spare parts are scarce/costly.
(b) Problems and solutions (any four pairs): destruction of crops – create grazing reserves/ranches; clashes with farmers – laws, dialogue and demarcated routes; spread of animal diseases – vaccination and quarantine; overgrazing and soil degradation – controlled stocking and rotational grazing; loss of weight and death of animals on the way – ranching and feed supplements; theft of animals – ranching and security.

Each problem in (b) must have its own matching solution.

(a) Any six: beautify homes and surroundings; provide shade; act as windbreaks; check erosion; serve as fences/hedges; provide income when sold; reduce noise and dust; some are medicinal; give recreation and fresh air.
(b) Any four: mosaic pattern of yellow and green on leaves; leaf curling and distortion; reduced leaf size; stunted plants; small or few tubers.
(c)(i) Selective exploitation: only mature trees of the wanted species and size are felled, leaving young ones to grow.
(ii) Regeneration: renewing a forest after felling, naturally (seeds, coppice) or by planting seedlings.
(iii) Taungya: farmers grow food crops between young forest trees, tending the trees while they farm until the tree canopy closes.

Keep the explanations in (c) short and precise.

(a) Any four: some are used as food or vegetables; some are medicinal; serve as livestock feed; act as cover to reduce erosion; add organic matter when they rot; some are ornamental; serve as mulch.
(b) Biting and chewing insects – grasshopper, beetles, caterpillars, termites; piercing and sucking insects – aphids, cotton stainer, mealybug, mosquito; boring insects – stem borer, weevils, pod borer.
(c) Any three: grazing on natural or established pasture; cut-and-carry (zero grazing/soilage); conserved as hay; conserved as silage.

Two examples are needed for each of the three groups.

(a)(i) Pests: animals that harm livestock or reduce their productivity, e.g. by attacking or disturbing them.
(ii) Pathogens: disease-causing organisms (bacteria, viruses, fungi, protozoa).
(iii) Vectors: organisms that carry disease organisms from one animal to another.
(iv) Parasites: organisms that live on or in a host and feed on it, harming it.
(b) Pest – rat/tick/fly; pathogen – Bacillus anthracis/virus of rinderpest; vector – tsetse fly (or tick); parasite – tapeworm/liver fluke/tick/louse.
(c) Cut the green forage at the right stage; chop it into short pieces; fill the silo and compact it to remove air (add molasses if needed); seal it airtight and leave it to ferment for about 3–6 weeks.

Silage steps: cut, chop, compact, seal.

(a) Any four: Leghorn; Isa Brown; Harco; Nera Black; Black Olympia; Rhode Island Red; Hy-line; Bovans.
(b)(i) Water: regulates body temperature; transports nutrients and wastes; aids digestion.
(ii) Minerals: build bones and teeth; form eggshells; needed for blood (iron) and body processes.
(iii) Antibiotics: prevent/control bacterial infections; improve growth and feed use.
(iv) Protein: growth and repair of tissues; production of eggs, milk and meat; forms enzymes and hormones.
(c) Any four: higher productivity per animal; better disease and parasite control; efficient use of feed and land; easy record keeping and management; protection from thieves and predators; animals do not destroy crops; manure collected easily.

Two functions for each of the four diet components.

(a) Any three: planning farm activities; organising and supervising workers; decision making on what and how much to produce; keeping records; marketing produce; controlling and coordinating resources.
(b)(i) Appreciation: increase in the value of a farm asset over time (e.g. land, growing animals).
(ii) Salvage value: the value (price) of an asset at the end of its useful life when it is sold or scrapped.
(iii) Farm budget: an estimate of the expected costs and returns of a farm plan for a future period.
(iv) Farm inventory: a complete list of the farm's assets and their values at a given date.
(c) Any five: good knowledge of agriculture; good communication skills/speaks local language; patient and friendly; honest and trustworthy; respects farmers' culture; hardworking and dedicated; resourceful and a good organiser.

Definitions in (b) should be one clear sentence each.

(a)(i) When more and more units of a variable input are added to a fixed input, the extra output from each additional unit eventually begins to fall.
(ii) Some factor (e.g. land) is fixed, so each extra unit of the variable factor has less of the fixed factor to work with.
(b)(i) Salvage value = selling price at end of use = ₦30,000.00.
(ii) Total depreciation = ₦100,000 − ₦30,000 = ₦70,000.00.
(iii) Annual depreciation = ₦70,000 ÷ 10 years (1990–2000) = ₦7,000.00 per year.
(c) Any seven: too few extension workers; poor transport/mobility; illiteracy of farmers; poor funding; inadequate teaching aids; poor remuneration of agents; language barriers; farmers' conservatism; poor research–extension linkage; lack of credit and inputs to apply new methods.

Show the working in (b): cost minus salvage value, then divide by the years of use.