WAEC Agricultural Science 2025 Theory Past Questions

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(a) Causes of food shortage in West Africa (any six): - Poor storage facilities - Pest infestation - Disease outbreak - Rural-urban migration - Desert encroachment/desertification - High population growth - Environmental degradation/erosion - Climate change/global warming - War/conflict/political instability/insecurity - Natural disaster/bush fire/wildfire/drought/flooding/earthquake/landslide (b) Governmental organizations (any four): - River Basin Development Authority - National Agricultural Insurance Company - Agricultural Development Bank - National Agricultural Land Development Authority - Agricultural Development Projects/programmes (c)(i) Field operations powered by the tractor: - Ploughing - Harrowing - Ridging - Planting - Fertilizer application (ii) Reasons it is difficult for farmers to acquire tractors (any five): - High cost of purchase/high import duties - High cost of maintenance/high cost of fuelling - Inadequate capital/poverty/credit facilities - Inadequate spare parts - Inadequate technical know-how

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(a) Ways nutrients are depleted from the soil (any four): - Leaching: encourages percolation of mineral salts from the topsoil to the subsoil, making nutrients unavailable to plants. - Plant uptake/removal: nutrients removed by harvested crops or grazing animals are permanently lost from the soil. - Bush burning: causes volatilization of nutrients; humus and microorganisms are also depleted. - Oxidation and reduction reactions: result in the loss of organic minerals and gaseous elements from the soil. - Soil erosion: fertile topsoil is carried away by wind or water, removing most of the available nutrients. - Continuous cropping: without replenishing lost nutrients leads to nutrient depletion. (b)(i) Advantages of applying green manure (any three): - Adds primary nutrients such as nitrogen and phosphorus/improves soil fertility - Improves soil aeration - Helps bind soil particles together - Adds organic matter to the soil - Increases the population of soil microorganisms - Helps check soil erosion - Improves soil structure - Helps fix nitrogen in the soil - Encourages microbial decomposition/enhances microbial activities - Reduces soil temperature (ii) Disadvantages of applying green manure (any three): - May lead to weed infestation - Requires much labour/labour-intensive - Could lead to pest infestation - Takes a long time to prepare - Weather dependent (c) Reasons deforestation should be discouraged (any four): - Prevents global warming/climate change/greenhouse gas emissions - Prevents desert encroachment/desertification - Maintains balance in the ecosystem/prevents destruction of the ecosystem - Checks soil erosion - Prevents drought - Prevents extinction of forest trees/plants/animals and protects biodiversity - Prevents flooding of the environment

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(a) Completed table: Maize smut - Causal organism: Fungus (Ustilago maydis); One symptom: Large galls on the ear; One preventive/control measure: Plant resistant varieties. Damping off of tomato - Causal organism: Fungus (Pythium spp.); One symptom: Stunted growth/stems at soil level become weak, seedlings collapse resulting in death of plants; One preventive/control measure: Treat seeds with fungicides/use disease-free seeds, practice crop rotation, ensure good drainage in the nursery, avoid over-watering, soil sterilization, use resistant varieties. (b)(i) Ways wind affects crop production (any four): - Affects the rate of transpiration/evaporation in crops - Facilitates pollination of crops - Necessary for seed dispersal/dispersal of weed seeds - Transmits diseases - Facilitates pest infestation, e.g. grasshopper (ii) Ways light affects crop production (any four): - Supplies energy needed for photosynthesis - Affects the growth rate of crops - Determines the species of crops that grow in areas with different day length/photoperiodism - Enhances the ripening of fruits - Responsible for phototropism in crops (c) Human activities that promote deforestation (any four): - Logging/timber exploitation - Mining/oil exploration - Urbanization/industrialization - Road construction - Farming activities/agriculture

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(a) Cultivation of cotton: (i) Planting material: By seeds; By cuttings. (ii) Spacing: 30cm x 90cm; 45cm x 90cm; 60cm x 100cm. (iii) Two varieties (any two): Gossypium hirsutum; Gossypium barbadense; Gossypium arboreum; Gossypium herbaceum. (iv) Harvesting: Handpicking of lint; Mechanical harvesting with a cotton harvester/cotton picker. (v) Two pests (any two): Cotton stainer; Flea hopper; Thrip; Grasshopper; Bollworm. (vi) Two uses (any two): Used in the textile industry for garment making; Cotton seed oil is used for cooking; Cotton seed cake is used in compounding livestock feeds; Cotton seed oil is used for margarine and soap making; Hulls are used for fertilizer and synthetic rubber. (b) Advantages of introducing a new variety of banana (any five): - May introduce variability not present in existing crops - Produces new plant species - Produces superior varieties - Easy to perform - Quick and economical - The new crop adapts to the local environment - May enhance productivity/increase yield of banana (c) Routine management practices for layers in the battery cage (any four): - Feeding - Watering - Deworming - Isolation of sick birds - Vaccination - Culling of unproductive birds - Debeaking - Quarantine

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(a)(i) Reasons for fencing (any three): - Restricts the movement of animals - Prevents entry of intruders/predators/thieves, ensures farm safety - Used to divide pasture into paddocks/proper pasture utilization - Prevents overgrazing of pasture - Prevents introduction of parasites (ii) Reasons for adequate stocking (any three): - Ensures the required number of animals graze a pasture based on its carrying capacity - Ensures optimal productivity of the pasture - Reduces/minimizes competition among animals - Prevents overgrazing of the pasture - Prevents soil erosion/compaction (b)(i) Culling: The removal of weak/sick/diseased/unproductive/unthrifty/cannibalistic animals from a flock/herd. Culled animals are not returned to the flock/herd; this improves the overall productivity of the flock/herd. (ii) Dehorning: The process of removing the horns of livestock, done using a saw, hot iron, or caustic soda. It reduces space required and reduces injury to other animals and to the farmer/veterinarian. (iii) Castration: The removal/destruction of the testicles of male animals not required for breeding. It can be open/surgical or closed castration. Castrated animals become more docile/less aggressive and it improves the quality of meat. (c) Steps in propagation of oil palm in a nursery: - Selection of viable seeds - Soak seeds in water - Pack the soaked seeds in plastic bags - Place the plastic bags in a germinator for 80 days - Resoak the seeds in water for 3-8 days - Dry the seeds under shade - Pack the seeds in polythene bags for germination to occur - Plant germinated seedlings in the main nursery - Carry out nursery care such as watering, fertilizing and pest control

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(a)(i) Farm inventory: A complete listing of all the assets on a farm with their value in monetary terms (land, machinery, farm buildings, crops, livestock). It involves identification, physical counting and assigning monetary value to farm assets, and is carried out at the beginning and end of the farming season/accounting year. (ii) Depreciation: The reduction in the value of an asset as it is used over time; it also refers to the wear and tear of a farm asset with use. Fixed assets depreciate slowly while current assets depreciate quickly. (iii) Liability: The debt owed by a farm business to outside parties (creditors), including loans, mortgages, deferred revenue, bank overdrafts, accrued expenses and debts payable; liabilities may be long-term or short-term. (iv) Salvage value: The value of an asset or capital after its useful life, usually lower than its purchase/cost price. It is important in calculating the depreciation of a farm asset. (b)(i) Law of supply: All things being equal, the higher the price of a farm produce, the higher the quantity supplied, and vice versa. (ii) Factors affecting supply of farm produce (any three): Price of produce; Price of other produce/substitutes; Technology used in production/technological change; Changes in weather/climate; Natural disaster; Goal of the farmer; War/conflict/political instability. (c) Effects of weeds on farm animals (any five): - May be toxic when consumed by farm animals/could result in death - Could destroy the hide/skin of animals - May cause injury to animals, e.g. entangle the horns - Could taint/contaminate milk or reduce milk quality - Harbour disease pathogens - Harbour insect pests/predators