WAEC SSCE - Agricultural Science - 1993 (Essay)

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a) Rock weathering:

Rock weathering refers to the process by which rocks are broken down into smaller pieces and eventually into soil over time, due to the action of physical, chemical, and biological agents.

b) Four factors affecting soil formation:

1. Parent material: The type of rock from which the soil is formed determines its mineral content and physical properties.
2. Climate: Temperature, rainfall, and humidity affect the rate of weathering and the types of vegetation that can grow in a particular region, which in turn influences the type of soil that is formed.
3. Topography: The slope, aspect, and elevation of a landscape affect the amount of water and sunlight that soil receives, as well as its exposure to erosion.
4. Time: The longer a soil has been forming, the more mature it becomes, with more layers and greater diversity of organisms.

c) Four types of chemical weathering:

1. Hydrolysis: This is the chemical reaction between minerals in rocks and water. Water reacts with minerals in the rock, causing them to break down into smaller, more soluble compounds.
2. Oxidation: This is the reaction between oxygen and minerals in rocks, such as iron, which can result in the formation of rust. This process can weaken the structure of rocks and make them more susceptible to physical weathering.
3. Carbonation: This is the reaction between carbon dioxide in the atmosphere and minerals in rocks, particularly calcium carbonate. This reaction can lead to the dissolution of minerals in the rock and the formation of karst landscapes.
4. Acidification: This is the reaction between acidic substances, such as acid rain or plant roots, and minerals in rocks. Acidification can dissolve minerals in the rock and lead to the formation of caves and sinkholes.

Summary:

In summary, rock weathering is the process by which rocks are broken down into soil over time. Factors that affect the formation of soil include parent material, climate, topography, and time. Chemical weathering includes hydrolysis, oxidation, carbonation, and acidification, each of which can cause the breakdown of minerals in rocks and contribute to the formation of soil.

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(a) Climatic and soil requirements: Tomato is a warm-weather crop that requires a temperature range of 20°C to 30°C to grow. It requires well-drained soils with a pH range of 6.0 to 7.0. The soil should be rich in organic matter and have good water holding capacity.

(b) Land preparation: The land for tomato cultivation should be well prepared by plowing, harrowing, and leveling the field. This ensures that the soil is well aerated and free of clods and weeds.

(c) Nursery practices: Tomato seeds are usually sown in a seedbed or nursery to raise seedlings. The seeds should be sown in trays or pots filled with a seed-starting mix. The seeds need to be watered regularly and kept in a warm, sunny location until they germinate.

(d) Planting and spacing: Once the seedlings have grown to a height of about 10-15cm, they can be transplanted to the main field. The tomato plants should be spaced at a distance of 45cm to 60cm between rows and 30cm to 45cm between plants.

(e) Fertilizer application: Tomato plants require balanced fertilization with nitrogen, phosphorus, and potassium. Fertilizers should be applied before planting and then every 2-3 weeks after transplanting. Nitrogen should be applied in smaller quantities during fruiting to avoid excessive vegetative growth.

(f) Staking: Tomato plants are usually staked to support their growth and prevent them from falling over. The stakes can be made of bamboo, wood, or metal. The tomato plants should be tied to the stakes using soft ties to avoid damage to the stems.

(g) Harvesting: Tomato plants usually start producing fruit 2-3 months after transplanting. The fruits should be harvested when they are fully ripe but still firm. Tomatoes should be picked regularly to encourage further fruit production. The harvested tomatoes should be handled carefully to avoid bruising and damage.

In summary, the production of tomatoes requires suitable climatic and soil conditions, proper land preparation, nursery practices, planting and spacing, fertilization, staking, and harvesting techniques. By following these steps, farmers can ensure the successful growth and development of tomato plants, leading to a healthy and bountiful harvest.

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(a) Bush burning:

Bush burning involves the deliberate setting of fire to natural vegetation to clear land for farming. While this practice helps to clear land quickly, it can have negative effects on the soil. The intense heat from the fire can destroy organic matter, which is an essential component of healthy soil. It can also cause soil erosion and lead to the loss of nutrients, making it difficult for crops to grow.

(b) Overgrazing:

Overgrazing occurs when too many animals graze on a piece of land, leaving the vegetation depleted and the soil exposed. This practice can have detrimental effects on the soil as it leads to soil compaction and erosion. Overgrazing can also reduce soil fertility, making it difficult for plants to grow.

(c) Clean clearing:

Clean clearing involves the complete removal of all vegetation, including trees and bushes, from a piece of land. This practice can have negative effects on the soil as it leaves the soil exposed to erosion and can cause nutrient loss. It can also lead to a decrease in soil fertility, making it difficult for crops to grow.

(d) Fertilizer application:

Fertilizer application is a practice that involves adding essential nutrients to the soil to improve crop growth and yield. While this practice can have positive effects on the soil, such as improving soil fertility, it can also have negative effects if not done correctly. Overuse of fertilizers can lead to soil acidity, nutrient imbalances, and pollution of water sources. It can also lead to the buildup of salts in the soil, making it difficult for plants to grow.

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(a) Finance: One of the major problems of agricultural development in Nigeria is lack of adequate finance. Many farmers in Nigeria lack access to finance, which limits their ability to invest in modern farming techniques, purchase quality inputs, and improve their yields. This makes it difficult for farmers to expand their production and earn higher incomes. The lack of finance also limits the ability of agricultural companies to invest in research and development, which can lead to the development of better farming techniques and inputs.

(b) Farm input: Another factor that contributes to the problems of agricultural development in Nigeria is the lack of quality farm inputs. Many farmers in Nigeria use outdated and low-quality farming inputs, such as seeds, fertilizers, and pesticides. This leads to low productivity and poor crop yields. Additionally, the high cost of quality farm inputs makes it difficult for farmers to access and use them.

(c) Transportation: Transportation is another major problem of agricultural development in Nigeria. The poor state of the transportation system, especially rural roads, makes it difficult for farmers to transport their products to markets. This often results in post-harvest losses, as perishable crops such as fruits and vegetables are unable to reach the markets in time. The high cost of transportation also reduces the profitability of farming, as farmers have to pay high prices to transport their products.

(d) Storage and processing facilities: Lack of proper storage and processing facilities is also a problem of agricultural development in Nigeria. Many farmers do not have access to proper storage facilities, which leads to post-harvest losses due to spoilage and insect infestation. Additionally, the lack of processing facilities limits the ability of farmers to add value to their products, which reduces their profitability. This limits the ability of farmers to earn higher incomes and reinvest in their farming activities.

In conclusion, finance, farm input, transportation, and storage and processing facilities are some of the major factors that contribute to the problems of agricultural development in Nigeria. Addressing these challenges will require significant investments in infrastructure, research and development, and policy reforms to support the growth of the agricultural sector.

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(a) Two functions of a cultivator are:

1. To break up and loosen soil to prepare it for planting by removing weeds, rocks, and other debris. This helps to create a more suitable environment for crops to grow and flourish.

2. To mix in organic matter or fertilizers into the soil, which provides essential nutrients to crops and helps to improve soil fertility over time.

(b) Five tools or implements for each of the following farm processes are:

(i) Land preparation: Plow, disc harrow, rotavator, subsoiler, cultivator.

(ii) Planting: Seed drill, planter, dibber, transplanting machine, broadcast seeder.

(iii) Harvesting: Combine harvester, sickle, scythe, pruning shears, machete.

(iv) Crop processing: Thresher, winnower, grain dryer, rice mill, oil press.

(c) Four reasons why farmers cultivate small holdings are:

1. Food security: Cultivating small holdings can help to ensure that farmers have a reliable source of food for their families and local communities. By growing a variety of crops, farmers can also ensure that they have access to a diverse and nutritious diet.

2. Income generation: Small holdings can provide a source of income for farmers through the sale of crops and other agricultural products. This can help to support their families and improve their economic well-being.

3. Environmental sustainability: Small holdings can be managed using sustainable agricultural practices, which can help to conserve soil, water, and other natural resources. This can help to reduce the impact of farming on the environment and promote long-term ecological health.

4. Cultural heritage: Small holdings can also play an important role in preserving cultural heritage and traditional farming practices. By cultivating small plots of land using traditional methods, farmers can maintain and pass on important cultural knowledge and practices to future generations.

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(a) Cassava mosaic:

Symptoms:

1. Yellowing and mottling of leaves.
2. Stunted growth of the plant.

Control measures:

1. Use virus-free planting materials.
2. Remove and destroy infected plants.

(b) Groundnut rosette:

Symptoms:

1. Stunting of the plant.
2. Formation of rosettes, which are clusters of small, distorted leaves.

Control measures:

1. Plant resistant varieties.
2. Control aphid vectors, which can transmit the virus that causes the disease.

(c) Root-knot of okra:

Symptoms:

1. Galls or knots on the roots of the plant.
2. Yellowing and wilting of leaves.

Control measures:

1. Plant resistant varieties.
2. Rotate crops and use crop rotation practices.

(d) Bacterial blight of cotton:

Symptoms:

1. Water-soaked spots on leaves and stems.
2. Necrosis or death of infected plant tissues.

Control measures:

1. Use disease-free planting materials.
2. Apply copper-based fungicides to infected plants.

In summary, plant diseases such as cassava mosaic, groundnut rosettes, root-knot of okra, and bacterial blight of cotton can cause significant damage to crops. However, control measures such as the use of disease-free planting materials, plant rotation, and the use of resistant varieties, as well as the removal and destruction of infected plants, can help to manage and control the spread of these diseases.

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Agricultural extension plays several critical roles in the development of agriculture in Nigeria. Here are eight of them:

1. Technology transfer: Agricultural extension helps to transfer new technologies, best practices, and innovations to farmers to improve their productivity and income.

2. Education and training: Extension workers provide education and training to farmers on various aspects of agriculture, such as crop production, livestock management, soil fertility, and pest control.

3. Research and development: Extension workers are involved in research and development activities to identify and address the challenges facing farmers and to develop new technologies and practices that can improve agricultural production.

4. Market development: Extension workers assist farmers in identifying market opportunities and developing marketing strategies to increase their income from agriculture.

5. Networking: Extension workers facilitate networking among farmers, input suppliers, agribusinesses, and other stakeholders to promote collaboration and knowledge sharing.

6. Advisory services: Extension workers provide advisory services to farmers on issues related to production, marketing, finance, and other aspects of agricultural development.

7. Policy advocacy: Extension workers advocate for policies and programs that promote agricultural development and support the needs of farmers.

8. Climate change adaptation: Extension workers help farmers to adapt to the impacts of climate change by promoting climate-smart agriculture practices and providing information on climate risk management.

In summary, agricultural extension is critical to the development of agriculture in Nigeria, and its roles are diverse and encompass several aspects of agricultural development.

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(a)

1. Appreciation in agriculture refers to an increase in the value of an asset, such as land, livestock, or machinery. This can occur due to factors such as increased demand for a particular crop, improvements in infrastructure or technology, or natural resource depletion that makes land more scarce and valuable.
2. Depreciation in agriculture refers to a decrease in the value of an asset over time due to wear and tear, obsolescence, or other factors that reduce its usefulness or efficiency. This can be caused by factors such as age, inadequate maintenance, or changes in farming practices that make certain equipment or technology less relevant or useful.
3. Salvage value in agriculture refers to the estimated value of an asset at the end of its useful life. This value is based on factors such as the condition of the asset, market demand for similar assets, and other economic factors. Salvage value is used in calculating the depreciation of an asset over time.

(b)

1. The salvage value of the tractor is the amount for which it was sold when it was no longer useful for the farmer, which is N3,000.00.
2. The total depreciation of the tractor is the difference between its purchase price and its salvage value, which is N12,000.00 - N3,000.00 = N9,000.00.
3. The annual depreciation of the tractor is the total depreciation divided by the number of years the tractor was in use, which is (N12,000.00 - N3,000.00) / 9 = N1,000.00 per year.
4. There is no appreciation in this scenario because the value of the tractor decreased over time, from N12,000.00 to N3,000.00. Appreciation would occur if the value of the tractor had increased due to factors such as inflation or improvements in technology that made it more valuable over time.

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(a) Four methods of harvesting fish include:

1. Seine netting: This involves the use of a large net with weights at the bottom and floats at the top. The net is drawn through the water by boats or pulled onto shore, capturing fish in the process.
2. Trawling: This involves towing a large net behind a boat through the water. The net is designed to catch fish by entrapping them in its mesh as it moves through the water.
3. Longlining: This involves the use of a long line with baited hooks that are set at intervals along the line. The line is then dropped into the water and left to sit for a period of time before being retrieved, along with any fish that have been caught.
4. Gill netting: This involves the use of a net with small mesh size that hangs vertically in the water. Fish swim into the net and become entangled in the mesh.

(b) Four fishery regulations include:

1. Size limits: Regulations that specify minimum or maximum size of fish that can be caught and kept. These limits help to protect young or mature fish from being caught before they have had a chance to breed.
2. Bag limits: Regulations that limit the number of fish that can be caught and kept by an individual or group of individuals. These limits help to prevent overfishing and ensure that fish populations remain healthy.
3. Seasonal closures: Regulations that specify times of the year when fishing is prohibited. These closures help to protect fish during critical periods of their life cycle, such as spawning or migration.
4. Fishing gear restrictions: Regulations that limit the types of gear that can be used for fishing in certain areas. These restrictions help to prevent damage to marine habitats and reduce bycatch of non-target species.

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a) Eight functions of water in livestock management include:

1. Regulating body temperature: Water helps regulate body temperature by enabling sweating and panting, which dissipates heat from the body.
2. Transporting nutrients: Water is a key component of blood and other bodily fluids, which transport nutrients and oxygen to cells throughout the body.
3. Aiding digestion: Water is essential for digestion and helps move food through the digestive tract.
4. Lubricating joints: Water is a component of synovial fluid, which lubricates joints and reduces friction.
5. Flushing waste products: Water helps remove waste products, such as urine and feces, from the body.
6. Maintaining hydration: Water is essential for maintaining proper hydration levels in animals, which is necessary for overall health and wellbeing.
7. Supporting milk production: Lactating animals require more water to support milk production.
8. Supporting growth: Water is necessary for cellular growth and repair, which is especially important for young animals.

b) Eight essential mineral elements required in animal nutrition are:

1. Calcium
2. Phosphorus
3. Magnesium
4. Sodium
5. Chloride
6. Potassium
7. Iron
8. Zinc

c) Four functions of mineral elements in the body of animals are:

1. Structural support: Minerals such as calcium and phosphorus are important for bone formation and maintenance.
2. Enzyme function: Many minerals, such as iron and zinc, are essential components of enzymes, which catalyze biochemical reactions in the body.
3. Nerve and muscle function: Minerals such as sodium and potassium are important for nerve and muscle function, including transmitting nerve signals and contracting muscles.
4. Fluid balance: Minerals such as sodium and chloride help maintain proper fluid balance in the body, which is necessary for cellular function and overall health.