WAEC Agricultural Science 2011 past questions and answers

Agriculture provides jobs, foreign exchange and raw materials; it does not supply weapons.

Development brings more processing, food and productivity; mechanisation usually reduces the labour needed on farms.

The farmer does not own communal land, so he cannot pledge it as collateral for a loan.

Government helps agriculture through subsidies, development programmes and farm settlements.

Cattle distribution depends on pasture, rainfall and diseases such as trypanosomiasis, not on light.

At field capacity gravitational water has drained away; plants use the capillary water held between particles.

Farming, population growth and urban growth clear forests; game reserves protect them.

The topsoil (A-horizon) has the most organic matter, air and roots, so most organisms live there.

Micro-nutrients (trace elements) are essential but needed only in tiny amounts.

Particle size (texture) and arrangement (structure) decide the pore spaces that hold water.

Well-structured soil with good air and water actually supports more microbes.

Burning destroys organic matter and humus, which harms soil structure and fertility.

Axonopus is a grass; the others are legumes that fix nitrogen.

Basalt, granite and pumice are igneous rocks formed from molten magma.

Ammonium fertilizers make soil more acidic; ash, limestone and basic slag are alkaline.

Being usable only for certain crops is a limitation, not an advantage.

People tire easily and do little work compared with machines.

A compass gives the direction (bearing) of a line.

Tsetse flies spread trypanosomiasis, which kills work animals in the forest zone.

Plough first to turn the soil, harrow to break clods, then ridge.

Staking keeps the fruits off the damp soil, so they do not rot.

Ginger is grown from pieces of its rhizome.

Quarantine is a legal (regulatory) measure that stops diseased material entering a country.

Nitrogen moves from old to young leaves, so lower leaves turn yellow first.

Mealybugs carry the cocoa swollen shoot virus.

Tree belts in dry areas act as shelter belts that stop the desert spreading.

In taungya, farmers grow food crops between young forest trees.

Pineapple is mostly planted from suckers (also slips and crowns).

Sugarcane is a monocot (grass) with fibrous roots; the others have tap roots.

Grafting joins a scion onto a rootstock of a related plant.

Pests lose their host plant when a different crop follows, so their life cycle is broken.

Taking the spacing as 2.5 m × 4.0 m = 10 m² per plant: 20,000 m² ÷ 10 m² = 2,000 seedlings.

Dry, sunny weather lets bolls open and dry out, so the lint does not go mouldy.

All offspring are Tt, and T is dominant, so all are tall.

Tt × Tt gives 1 TT : 2 Tt : 1 tt.

Food is eaten, broken down, absorbed into the blood, then used by the cells.

Oxytocin causes milk let-down.

Newborn piglets cannot keep themselves warm and die of cold without extra heat.

The thermostat switches the heater on and off to keep the temperature steady.

A mature wether is not growing, pregnant or lactating, so it needs only a maintenance ration.

Young rabbits are bunnies (kits); kids are young goats, poults young turkeys and lambs young sheep.

Weight gain = 45 − 25 = 20 kg; FCR = feed ÷ gain = 60 ÷ 20 = 3 : 1.

P needs only 50 ÷ 20 = 2.5 kg of feed per kg gain, the lowest of the four (Q 3, R 4, S 5).

Yolk sac infection, coccidiosis and pullorum attack young chicks in the brooder; fowl pox is more common in older birds.

Piglet anaemia is caused by lack of iron, so iron injections are given.

Ascaris is a roundworm living in the intestine; the others are external parasites.

Tsetse flies carry trypanosomes, which cause trypanosomiasis.

A small bag-shaped net on a long handle used to scoop fish is a scoop net.

A heifer is a young cow that has not yet had a calf.

Oil palm takes years to start yielding, so it needs a long-term loan.

(₦100,000 − ₦25,000) ÷ 100 years = ₦750 per year.

By the law of demand, the price of a good is the main factor deciding how much people buy.

A durable asset gives service over many years.

Interest = 5% of 50,000 = 0.05 × 50,000 = 2,500.

Extension agents teach farmers new and improved farming practices.

(a)(i) Any three: development of insecticides, fungicides, herbicides, nematicides and rodenticides; spraying equipment; breeding of pest- and disease-resistant varieties; biological control agents; irradiation/fumigation of stored produce.
(ii) Any three: weather forecasts to fix planting and harvesting dates; forecasting of pest and disease outbreaks; measurement of rainfall, temperature, humidity and wind; cloud seeding; guidance on choice of crops and drying of produce.
(b)(i) Bulldozer: clearing bush and felling trees; uprooting stumps; levelling land; building farm roads.
(ii) Combine harvester: harvesting (cutting) cereals; threshing; cleaning/winnowing and bagging grain.
(iii) Tractor: pulling implements (ploughs, harrows, ridgers); haulage with trailer; powering stationary machines through PTO; lifting implements hydraulically.
(iv) Sprayer: applying pesticides and herbicides; applying liquid fertilizers or hormones.
(v) Planter: sowing seeds at the right spacing and depth; some apply fertilizer at planting.

"Pesticides" alone is too vague; name the type (insecticide, fungicide…).

(a) Any ten in a table, subsistence vs commercial: mainly for family vs mainly for sale; small capital vs large capital; family labour vs hired/skilled labour; small land vs large land; local varieties/breeds vs improved varieties/breeds; simple tools vs machines; few agro-chemicals vs much use of fertilizers and chemicals; low yield per hectare vs high yield; records rarely kept vs records kept; mainly food crops vs cash crops too; little processing and storage vs modern processing and storage; poor farmers vs rich farmers/companies.
(b)(i) Wind: advantage – free, renewable, clean; disadvantage – unreliable (only when windy), high initial cost, weak for heavy work.
(ii) Internal combustion engine: advantage – powerful and dependable, mobile; disadvantage – fuel is costly, pollutes air, needs skilled maintenance.
(iii) Electricity: advantage – clean, efficient, easy to use for many machines; disadvantage – not available in many rural areas, power failures, risk of shock, costly installation.

Set (a) out in two columns; each row must compare the same feature.

(a) Soil consistency is the way soil particles hold together, i.e. the soil's resistance to being deformed or broken, shown by its stickiness, plasticity, friability or hardness at different moisture levels.
(b)(i) Texture affects water-holding capacity, drainage and aeration, nutrient content, ease of root penetration and workability.
(ii) pH affects availability of nutrients, activity of micro-organisms (e.g. nitrogen fixers) and the kind of crops that grow well; very low pH makes Al and Mn toxic.
(c)(i) and (ii) any four with two ways each: crop rotation – different rooting depths use different layers; legumes add nitrogen; manuring (organic) – adds nutrients and humus, improves structure; fertilizer use – replaces nutrients removed by crops quickly; liming – raises pH and supplies calcium; cover cropping – checks erosion and adds organic matter; mulching – conserves moisture and adds humus; fallowing – lets soil recover nutrients and organic matter; erosion control – keeps the fertile topsoil.

Two ways are needed for each method in (c).

(a)(i) Tillage is the working (loosening, turning) of the soil with tools or machines to make it suitable for crop growth.
(ii) Primary tillage is the first, deep working of the soil that breaks and turns it (ploughing); secondary tillage follows it and breaks clods into a fine tilth and levels or ridges the soil (harrowing, ridging).
(b)(i) Green manuring: adds organic matter/humus; adds nutrients, especially nitrogen from legumes; improves soil structure and water holding; increases soil organisms; protects soil from erosion while growing.
(ii) Mulching: conserves soil moisture; suppresses weeds; reduces erosion; moderates soil temperature; adds organic matter when it rots.
(c) Any six: supplies water during the dry season/drought; allows all-year cropping; supplements irregular rainfall; makes dry land cultivable; softens soil for planting; can carry fertilizers (fertigation); controls soil temperature/frost; leaches excess salts; increases yield.

Show the difference in (a)(ii) by when and how each is done.

(a)(i) Raising new plants from parts of the parent other than seed, e.g. stems, roots, leaves, suckers, tubers.
(ii) Advantages: offspring are true to type; plants mature and fruit earlier; useful for plants that produce no viable seed; desirable traits easily kept. Disadvantages: diseases carried over from the parent; materials are bulky and perish quickly; no new varieties arise; costly to transport and store.
(b) Any four: crop rotation; early planting/harvesting; clean weeding/field sanitation; destroying crop residues; use of resistant varieties; trap cropping; proper spacing; mixed cropping.
(c) Any four: poison humans and animals; residues in food; kill beneficial insects and natural enemies; pollute soil and water; pests develop resistance; high cost; scorching of crops if overdosed.

Vegetative propagation advantages and disadvantages should not repeat each other.

(a) A field pest attacks crops while they are growing on the farm (e.g. stem borer, grasshopper); a storage pest attacks harvested produce in store (e.g. weevils, grain moth, rats).
(b) Any two: to avoid field pests such as weevils and birds; to avoid theft; to avoid rotting/mould in wet weather; to free the land for the next crop; to sell early at higher prices (green maize).
(c)(i) Introduction: bringing in a crop variety from another area or country, testing it and adopting it if it does well (acclimatisation).
(ii) Cross breeding: mating (crossing) two different varieties with desired traits so that offspring combine the good qualities of both; selection follows.
(d) Any six: yield potential; resistance to pests and diseases; maturity period; adaptability to local climate and soil; market demand/consumers' taste; storage quality; availability of planting material; drought tolerance; nutritive value.

Give examples of each kind of pest in (a).

(a) Any four: cheap source of feed (grass and legumes); grazing space for large herds; provides water and shade; serves as source of hay and silage; reduces cost of production; allows exercise and natural mating.
(b) The field is a rectangle 250 m × 114 m with a semicircle (radius 57 m) at each end.
Rectangle = 250 × 114 = 28,500 m²; two semicircles = πr² = 3.142 × 57 × 57 ≈ 10,208 m².
Total ≈ 38,708 m² ≈ 3.87 ha.
Area per animal = 3 m × 3 m = 9 m² = 0.0009 ha.
Carrying capacity = 3.87 ha ÷ 0.0009 ha ≈ 4,300 cattle on 3.87 ha.
(c)(i) Dipping: kills external parasites (ticks, lice); prevents tick-borne diseases.
(ii) Vaccination: protects animals from specific diseases; prevents disease outbreaks and losses.
(iii) Artificial insemination: one good male serves many females; spreads improved genes; prevents spread of sexually transmitted diseases; no need to keep a bull.

In (b) remember the two half-circles at the ends.

(a) Advantages: birds are protected from predators and weather; litter becomes good manure; less labour than free range; records and feeding are easy; good for large numbers. Disadvantages: diseases and parasites spread easily; egg eating and cannibalism; dusty litter; dirty eggs laid on floor; more space than battery.
(b)(i) Castration of goats: makes them docile and easy to handle; prevents unwanted breeding; improves meat quality and removes the strong smell; faster fattening.
(ii) Creep feeding of piglets: supplements sow's milk; faster growth and higher weaning weight; prepares piglets for weaning; reduces stress on the sow.
(c) Any four: White Fulani; Red Bororo; N'Dama; Muturu; Sokoto Gudali; Keteku; Kuri; West African Shorthorn.

Name breeds, not species, in (c).

(a)(i) Farm credit is money or inputs lent to a farmer for farm use, to be repaid later, usually with interest.
(ii) Any five: commercial banks; Bank of Agriculture/agricultural development banks; co-operative societies; government agencies/schemes; money lenders; friends and relatives; esusu/thrift societies; merchants.
(b)(i) Individual (farm and home visits); group methods (meetings, demonstrations); mass media methods (radio, TV, newspapers).
(ii) Mass media method (e.g. radio/television).
(iii) It reaches very many farmers over a wide area at once; it is fast, which matters in an emergency; it is cheap per farmer reached.
(iv) Any three: some farmers have no radio/TV; power failure; language barrier; no chance for questions/feedback; illiterate farmers cannot read print media; message may be misunderstood.

The answer to (b)(ii) is the mass media method; give reasons tied to speed and reach.

(a)(i) Agricultural extension is the service that educates farmers and carries improved farming practices and research findings to them, and their problems back to researchers.
(ii) Any five: mismanagement and embezzlement of funds; poor leadership; illiteracy of members; lack of capital; disloyalty and lack of commitment of members; government interference; late repayment of loans; quarrels among members.
(b)(i) Any three discussed: shortage and high cost of farm labour; farming left to old people, so production falls; food shortage and higher food prices; abandoned farms and slow adoption of new ideas.
(ii) Any three: provide rural amenities (roads, water, electricity, health centres); give credit and inputs to young farmers; mechanise farming to make it attractive; establish agro-industries in rural areas; youth farm schemes and better prices for produce.

Discuss effects on farming, not on cities.