WAEC Agricultural Science 2023 Theory Past Questions

Model answer

(a) Credit is a refundable loan given to a farmer with the aim that the farmer will repay it over a period of time while Subsidy is a non-refundable aid/assistance given to farmers in order to boost agricultural production. (b) Agricultural inputs subsidised by government: Fertilizer; Improved seeds; Irrigation equipment; Improved breeds of animals; Veterinary services/vaccines/drugs; Farm machinery/tractor/bulldozer/farm implement; Agrochemicals/herbicides/pesticides/insecticides. (c) Periodic maintenance practices on a tractor: Tighten loose bolts and nuts; Change oil filter cartridge; Weld broken metal parts; Replace worn out/damaged parts; Paint the tractor panel to prevent rusting; Lubricate moving parts; Recharge the battery; Inflate tyre pressure when necessary; Change engine oil; Check the fan belt for correct tension; Top up water in the radiator when necessary; Adjust brakes and clutch pivots; Check oil level in the hydraulic system oil tank. (d) Precautions when operating farm machinery: Follow manufacturers' instructions/manuals; Wear protective clothing/reflective jackets; Keep machinery in good working condition; Do not operate farm machinery under the influence of drugs/alcohol; There should always be a first aid kit on the farm; Skilled/trained personnel should operate machinery; Do not operate machinery when tired/sleepy/sick.

Model answer

(a)(i) Agricultural ecology is the study of crop plants and farm animals in relation to their environment. Agricultural ecology is the interaction of crop plants and farm animal with the biotic and abiotic environment. (ii) Ecosystem refers to the interaction of a community of biotic components (plants and animals) with their abiotic components (non-living things). (b)(i) Biotic components of a farm ecosystem: Crops; Protozoa; Microorganism/Virus/Bacteria; Producers/autotrophs; Farm animals; Consumers/heterotrophs; Soil living organisms/Earthworms. (ii) Abiotic components of a farm ecosystem: Temperature; Wind/air/storm; Relative humidity; Sunlight; Rainfall/precipitation; Dust; Rock Minerals; Wild fire; Soil; Water. (c) Precautions for storage of bags of maize in a store: Storehouse should be rain proof; Ensure adequate ventilation in storehouse; Windows should be netted against insects; A simple metal roof should be constructed; Floors and walls should be cemented with no cracks for insects/rats to hide. (d) Examples of bedding plants: Zinnia; Morning glory; Cana lily; Lantana IV; Gloriosa; Amarantus; Crotolaria; Water lettuce; Marigold and so on (any four).

Model answer

(a)(i) Causal organism: Root knot nematode/Meloidogyne spp. (ii) Mode of transmission: Nematodes are soil borne/through the soil. (iii) Symptoms: Enlargement of certain cells of the roots in form of knots; Wilting of plants; Retarded growth; Reduction in yield. (iv) Prevention and control measures: Practising crop rotation; Good farm sanitation; Use of resistant varieties; Soil sterilization; Use of nematicides. (b)(i) Fertilizer application effects: Adds nutrients to the soil/enhances the productive capacity of the soil; Continuous use of nitrogenous fertilisers e.g. sulphate of ammonia increases soil acidity; Excessive use of fertilisers reduces the availability of some essential plant nutrients e.g. potassium and calcium; Prolonged use of fertilizers leads to a reduction in some soil microorganisms; Excessive use of fertilizers leads to ground-water contamination. (ii) Clean clearing effects: Destruction of soil structure/soil compaction; Exposes the soil to erosion; Encourages leaching of soil nutrients; Results in increased rate of evaporation; Leads to increase in soil temperature. (iii) Overgrazing effects: Leads to soil compaction; Exposes the soil to agents of erosion; Increases the evaporation rate of soil water; Results in low soil fertility; Destroys soil structure. (c) Agricultural uses of land: Crop production; Wildlife conservation/game reserve; Livestock production farming; Forestry; Horticulture/snail farming.

Model answer

(a) Steps in planting cassava stem cuttings: Collect healthy cassava stem cuttings of about 25cm long each with a good number of buds/nodes; Plant the stem cuttings in slanting position or at an angle of 45 deg; Bury about 3/4 of the stem cuttings in the soil with the buds facing upwards; Observe the buds above the soil surface which develop new shoots while the buds buried in the soil develop new roots. (b) Uses of cassava tubers: Can be processed into Garri/flakes/chips/flour/tapioca/consumed as food; Cassava flour is used in baking; Cassava meal/chips/peels are used as animal feed; Alcohol can be extracted from the tubers; Can be processed into starch. (c) Spacing = 100cm x 100cm = 1m x 1m = 1 sq.m. Area of farmland = 1.5ha = 1.5x10,000 sq.m = 15,000 sq.m. (i) Expected number of yam plants = Area of farmland/spacing = 15,000/1 = 15,000 yam plants. (ii) Total weight of yam tubers harvested = Average weight of one yam tuber x number of plants = 3.5kg x 15,000 = 52,500 kg. (d) Diet is the amount of feed regularly given or consumed by a farm animal, while Ration is the amount of feed that is given to a farm animal daily/over a 24 hour period.

Model answer

(a) Symptoms: constant cough and production of stringy sputum with blood or pus in pigs -- Disease: Tuberculosis -- Prevention and Control: Isolation of infected animal; Disinfection of animal pens and equipment/good farm sanitation; Treatment of infected animals/use of appropriate drugs; Inspection of animal before and after slaughtering/meat inspection. Symptoms: Ring-like lesions on the skin of farm animals; Constant itching -- Disease: Ringworm -- Prevention and Control: Disinfection of livestock pens and equipment/good farm sanitation; Treatment with fungicides; Avoiding overcrowding. Symptoms: Blood-stained diarrhoea; Pale comb in poultry -- Disease: Coccidiosis -- Prevention and Control: Addition of coccidiostat to feed and water; Avoid wet litter/feed; Avoid contamination of feed and water with droppings; Good farm sanitation. (b)(i) Queen bee: Lays eggs; Secrete chemicals/pheromones/scent that help regulate the unity of the bee colony. (ii) Worker bee: Cleaning of colony; Feeding the queen, drones and larvae; Collecting pollen and nectar; Making wax; Protecting the colony from invaders. (c) Reasons a compost pit should be covered: to retain moisture; to maintain heat/temperature for decomposition; to prevent leaching of nutrients by rain; to prevent excessive drying by sun/wind; to prevent pest/rodent infestation; to hasten the decomposition process.

Model answer

(a) Wellness Farms Profit and Loss Account for the year ended 31st December 2016: Income: Sale of eggs N240,000; Sale of spent layers N100,000; Eggs consumed by farmer N10,000; Closing valuation N600,000. Total Income = N950,000. Expenditure: Opening valuation N400,000; Cost of point-of-lay N200,000; Cost of feed N150,000; Cost of drugs N10,000; Transportation costs N10,000; Wages paid to workers N80,000. Total Expenditure = N850,000. Net Profit = Total Income - Total Expenditure = N950,000 - N850,000 = N100,000. (b) Problems faced by financial institutions in granting credit to crop farmers: High risk of loan default due to crop failure; Lack of collateral security by farmers; High cost of administering small loans to scattered farmers; Poor record keeping by farmers; Unpredictable weather/climate affecting repayment ability; Fluctuating market prices for produce affecting farmers' income. (c) Characteristics of Centrosema pubescens: It is a leguminous cover crop; It is drought resistant; It suppresses weed growth; It fixes nitrogen in the soil; It has trifoliate leaves; It is a perennial climbing/twining plant.