WAEC SSCE - Agricultural Science - 2019

Détails de la réponse

The protective function of forests that is not included in the list is serving as a source of firewood. Forests play a crucial role in protecting the environment by conserving soil, acting as a windbreak, and purifying the air. However, they are not specifically designed to serve as a source of firewood. Instead, they provide a habitat for wildlife, regulate the water cycle, and help mitigate climate change by absorbing carbon dioxide from the atmosphere.

Détails de la réponse

Détails de la réponse

The growing of only one type of crop on a piece of land repeatedly year after year is called monoculture. This farming practice involves planting the same crop in the same area each year, without changing the crop species or rotating with different crops. Monoculture has several advantages, such as allowing farmers to specialize in one crop and therefore increasing efficiency and yield, but it also has significant disadvantages, including depleting soil nutrients, increasing pest and disease pressure, and reducing biodiversity. Farmers often use chemical fertilizers and pesticides to compensate for these problems, leading to environmental and health concerns.

Détails de la réponse

To calculate the percentage moisture content of the soil sample, we need to first find out the weight of the water that was present in the original sample. The weight of water in the original sample can be found by subtracting the weight of the dried sample from the weight of the original sample: Weight of water = Weight of original sample - Weight of dried sample = 25 kg - 20 kg = 5 kg Now, we can use the following formula to calculate the percentage moisture content: Percentage moisture content = (Weight of water / Weight of original sample) x 100% Substituting the values we obtained, we get: Percentage moisture content = (5 kg / 25 kg) x 100% = 20% Therefore, the percentage moisture content of the soil sample is 20%.

Détails de la réponse

Animal P is the most efficient feed converter among the four animals. This is because it gained 20kg of weight by consuming only 50kg of feed. In contrast, animal Q consumed 90kg of feed to gain 30kg of weight, animal R consumed 100kg of feed to gain 25kg of weight, and animal S consumed 150kg of feed to gain 30kg of weight. Therefore, animal P requires the least amount of feed to gain weight, making it the most efficient feed converter among the four animals.

Détails de la réponse

Sedimentary rock is a type of rock that is formed from the accumulation of materials that have been transported by water, wind, or ice and then deposited. Over time, these deposits build up and get compressed, which eventually turns them into solid rock. Some examples of sedimentary rock include sandstone, limestone, and shale. This type of rock is important because it often contains important information about the environment and climate of the past.

Détails de la réponse

Détails de la réponse

Commercial farming is the large scale agricultural production for sale. This means that farmers grow crops or raise animals on a big scale with the intention of selling them to others for a profit. The crops and animals are not just grown for the farmer's own family to consume, but rather to be sold to the market. This type of farming is different from a small family farm, where the focus is on producing food for the family's own consumption, and not necessarily for sale.

Détails de la réponse

The hormone responsible for oestrus in farm animals is oestrogen. Oestrus is a term used to describe the period of time when a female animal is sexually receptive and fertile. During this time, the levels of oestrogen in the animal's body increase, which triggers a series of physiological changes, including an increase in sexual behavior and a swelling of the reproductive organs. This signals to male animals that the female is ready to mate, and helps to ensure successful fertilization. So, in simple terms, oestrogen is the hormone that causes the female animal to go into heat and become fertile.

Détails de la réponse

In animal production, immature spermatozoa are stored in the epididymis. The epididymis is a long, coiled tube located at the back of the testes, where spermatozoa mature and are stored. It connects the testes to the vas deferens, which carries sperm to the urethra and out of the body during ejaculation. The urethra is a tube that carries urine and semen out of the body through the penis. It does not play a role in sperm storage. The scrotum is a sac that holds the testes, which produce sperm. It provides the right temperature for sperm production, but it does not store mature sperm. The prostate gland is a small gland located near the bladder, which produces a fluid that nourishes and protects sperm. However, it does not play a role in sperm storage either. Therefore, the correct answer is the epididymis, which is where immature spermatozoa are stored in animal production.

Détails de la réponse

Magnesium is essential for chlorophyll formation. Chlorophyll is a green pigment found in plants that plays a crucial role in photosynthesis, the process by which plants make their own food. Magnesium is a central component of chlorophyll molecules, and without it, chlorophyll cannot be produced. This means that plants with a magnesium deficiency will have stunted growth and yellowing leaves, as chlorophyll is necessary for the plant to perform photosynthesis and produce energy.

Détails de la réponse

The following statements are advantages of mulching: I. Controls weeds II. Conserves soil moisture Mulching involves covering the soil surface around plants with a layer of organic material such as leaves, grass, straw, or wood chips. The organic material acts as a barrier that blocks sunlight from reaching weed seeds, preventing them from germinating and growing. Therefore, mulching can help control weeds naturally without the use of chemicals. Mulch also helps to conserve soil moisture by reducing evaporation from the soil surface. It helps to retain moisture by slowing down water loss from the soil through evaporation. As a result, plants can access the water they need for growth and development, and water is used more efficiently. However, mulching does not increase soil temperature or reduce soil pH. In fact, mulching can help to moderate soil temperature by keeping the soil cooler in hot weather and warmer in cool weather. Mulching does not have a direct impact on soil pH either. Therefore, the correct answer is: I and II.

Détails de la réponse

All of the factors listed are important for successful incubation of eggs, but if we had to choose the least important factor, it would be light. While some species of birds may require specific lighting conditions for successful incubation, many birds do not require any specific lighting at all. Temperature is a crucial factor because eggs need to be kept at a consistent temperature for proper development. Ventilation is also important because it helps to regulate the exchange of oxygen and carbon dioxide, which is necessary for the growth of the embryo inside the egg. Humidity is also crucial because it helps to prevent the egg from drying out and ensures proper moisture levels for the embryo. In summary, while light can be important for some species, it is generally less important than temperature, ventilation, and humidity for successful incubation of eggs.

Détails de la réponse

Détails de la réponse

Sexual propagation of ornamental plants involves the use of seeds. Propagation is the process of creating new plants from existing ones. Sexual propagation is one of the two main methods of plant propagation, the other being asexual propagation. Sexual propagation involves the use of seeds to produce new plants. Seeds are the reproductive structures of plants that contain an embryo and a supply of nutrients for the new plant. They are produced when the male and female parts of a flower come together and fertilization occurs. The resulting seeds can be planted in soil, where they will germinate and grow into new plants. Sexual propagation has the advantage of producing genetically diverse offspring, which can lead to new and unique plant varieties. It is also a natural way for plants to propagate themselves in the wild. In summary, sexual propagation of ornamental plants involves the use of seeds, which are the reproductive structures of plants that contain an embryo and a supply of nutrients for the new plant.

Détails de la réponse

Détails de la réponse

The breed of cattle that is considered "exotic" is the friesian. This breed is considered exotic because it originally comes from the Netherlands and is not commonly found in many countries. It is known for its high milk production and black and white coloring. The other breeds, Sokoto gudali, Ndama, and Muturu are breeds that are native to African countries and are more commonly found in those regions.

Détails de la réponse

Détails de la réponse

Détails de la réponse

The practice of measuring and mapping out the size, position and boundary of a farmland is called surveying. This involves using tools and techniques to accurately determine the boundaries of the land, its size and its location on a larger map. Surveying is an important aspect of farming as it helps farmers to know exactly where their land begins and ends, which can be useful in preventing disputes with neighboring farms or in accurately applying fertilizers and other inputs to the crops.

Détails de la réponse

Détails de la réponse

A biotic factor refers to a living component of an ecosystem that affects other organisms in that ecosystem. In the context of agricultural production, biotic factors can include pests, diseases, and predators. Out of the given options, the biotic factor affecting agricultural production is the predator. Predators such as insects, rodents, and birds can feed on crops and cause significant damage to agricultural production. Farmers have to implement measures such as installing nets or using pesticides to protect their crops from predators. While rainfall, humidity, and temperature are important abiotic factors that can also affect agricultural production, they are not considered biotic factors as they are not living components of the ecosystem.

Détails de la réponse

Détails de la réponse

One disadvantage of farm mechanization is the displacement of farm workers. As farms become more automated and rely on machines to perform tasks that were once done by hand, there is less need for human labor. This can lead to job loss and unemployment in rural communities that depend on agriculture for their livelihoods. Additionally, the loss of jobs can result in a decline in the quality of life for farmers and their families, as they may be forced to move to urban areas in search of work. This can have negative impacts on the social fabric and economic stability of rural communities.

Détails de la réponse

Vegetative growth in fish ponds refers to the growth of plants and algae in the pond water. This type of growth can have several effects on the environment of the pond and the fish living in it. First, the growth of plants and algae can provide shade and shelter for the fish, making their movements easier. The plants and algae also help regulate the acidity of the water, which is important for the health of the fish. Second, the growth of these organisms can increase the turbidity of the pond water, which means that it can become cloudier. This can be beneficial for some species of fish, as it provides them with more hiding places and can reduce the amount of light reaching the bottom of the pond, which can limit the growth of undesirable plants. Finally, the growth of plants and algae in the pond can also moderate the temperature of the water. This is important because fish are cold-blooded animals and their metabolism is affected by changes in water temperature. The plants and algae can help keep the water temperature stable, which is beneficial for the health and growth of the fish.

Détails de la réponse

Détails de la réponse

Détails de la réponse

The vector of leaf curl disease of cotton is the whitefly. A vector is a type of insect that can spread a disease from one plant to another. In the case of leaf curl disease in cotton, the whitefly is the insect that spreads the virus that causes the disease. The whitefly feeds on the sap of the cotton plant, and in doing so, it can spread the virus from an infected plant to a healthy plant. This can lead to the spread of the disease and can cause significant damage to cotton crops.

Détails de la réponse

Détails de la réponse

Détails de la réponse

Corns, rhizomes and tubers are examples of underground stems. Stems are the part of the plant that supports leaves, flowers, and fruits. They also transport water, nutrients and sugars from the roots to other parts of the plant. Some plants have stems that grow underground, which are called underground stems. Corns, rhizomes, and tubers are all examples of underground stems. Corns are thickened underground stems that store food for the plant. They are commonly found in grasses like corn, wheat, and barley. Rhizomes are horizontal underground stems that produce roots and shoots at their nodes. They can grow new plants and help the plant spread quickly. Ginger and turmeric are examples of plants that have rhizomes. Tubers are enlarged, fleshy underground stems that store food for the plant. They often have buds, or "eyes," that can sprout new plants. Potatoes are the most well-known example of tubers. In summary, corns, rhizomes, and tubers are all types of underground stems that allow plants to store food and propagate themselves.

Détails de la réponse

Détails de la réponse

The implement used for primary tillage is a plough. Primary tillage is the first stage of soil cultivation where the soil is broken up and turned over to a significant depth to prepare it for planting. A plough is a farming tool with one or more blades that are used to cut, lift and turn over the soil in preparation for planting. The plough blade is designed to penetrate the soil and cut a furrow, which is then turned over to expose the nutrient-rich soil below the surface. This process helps to loosen and aerate the soil, which makes it easier for plants to take root and grow. On the other hand, cultivators, harrows, and ridgers are all secondary tillage tools that are used after primary tillage to further prepare the soil for planting. Cultivators are used to remove weeds and break up the soil surface to improve water penetration, while harrows are used to level the soil and break up clumps of soil. Ridgers are used to create ridges or furrows in the soil to plant crops. In conclusion, a plough is used for primary tillage, which is the first stage of soil cultivation where the soil is broken up and turned over to prepare it for planting. Other tools like cultivators, harrows, and ridgers are used for secondary tillage to further prepare the soil for planting.

Détails de la réponse

The statement that "it can be relocated" is not correct. Land is a finite and immovable resource, meaning it cannot be relocated. It is a natural resource that is situated in a specific location and cannot be moved to another location. This is why the location of land is so important in real estate, as it affects the value and use of the land.

Détails de la réponse

Bone meal is included in the diet of livestock to supply calcium and phosphorus. Bone meal is made from crushed animal bones that have been finely ground into a powder. This powder is a rich source of calcium and phosphorus, which are both essential minerals for the growth and development of livestock. Calcium is important for strong bones and teeth, while phosphorus is needed for energy metabolism, cell growth, and maintenance of pH balance in the body. By providing these essential nutrients in the diet, bone meal helps to ensure that livestock remain healthy and develop properly.

Détails de la réponse

Determining the equilibrium price of rice depends on the market demand and supply of rice. The equilibrium price is the price at which the quantity of rice demanded by buyers is equal to the quantity of rice supplied by sellers. If the demand for rice is high and the supply is low, the price of rice will increase until buyers are willing to buy less rice or sellers are willing to supply more rice. Conversely, if the supply of rice is high and the demand is low, the price of rice will decrease until buyers are willing to buy more rice or sellers are willing to supply less rice. Without knowing the current market demand and supply of rice, it's impossible to determine the equilibrium price of rice. Therefore, none of the options provided (N1.00, N2.00, N3.00, or N4.00) can be the correct answer. The equilibrium price of rice can only be determined by analyzing the current market conditions of demand and supply.

Détails de la réponse

Détails de la réponse

The soil horizon that is not supportive of the growth of tree crops is the one that is not suitable for the growth and development of the roots of the trees. This can be due to several reasons, such as being too shallow, too rocky, too dry, or having poor drainage. In general, tree crops need a deep and well-drained soil to grow strong and healthy roots. A soil that is shallow or has poor drainage can lead to water-logged roots, which can cause the tree to become stunted or even die. Similarly, soil that is too rocky or dry may not have enough nutrients and moisture for the roots to grow, leading to poor tree growth. Therefore, the soil horizon that is not supportive of the growth of tree crops is the one that does not provide the right conditions for the roots to grow and develop.

Détails de la réponse

Détails de la réponse

Détails de la réponse

Land availability is affected by various socio-cultural factors, such as religion, social norms, and traditional beliefs. For example, in some cultures, land is considered a sacred resource and cannot be bought or sold. This can limit land availability, particularly in areas where these cultural beliefs are prevalent. Therefore, the correct option is religion, as it is a socio-cultural factor that can affect land availability. Soil type, topography, and mining are environmental and economic factors that can affect land availability, but they are not directly related to socio-cultural factors.

Détails de la réponse

Détails de la réponse

Détails de la réponse

Détails de la réponse

A wallow is a muddy area or pool of water that is provided in pig pens. The main purpose of a wallow is to cool down the body temperature of pigs. Pigs do not have sweat glands, so they cannot regulate their body temperature through sweating like humans. They cool themselves by rolling in mud or water, which helps to dissipate heat from their bodies. Therefore, the correct option is that a wallow is provided in the pen of pigs to cool the temperature of pigs. It does not reduce feed intake or increase water intake, nor does it enable pigs to swim.

Détails de la réponse

The area of a rectangular farmland can be calculated by multiplying its length by its width. In this case, the length of the farmland is 50 meters and the width is 25 meters, so the area is 50m x 25m = 1250 square meters. However, the answer is not in square meters but in hectares, which is a unit of area commonly used to measure land. One hectare is equal to 10,000 square meters. To convert the area from square meters to hectares, we divide the area by 10,000: 1250 square meters / 10,000 = 0.125 hectares. So, the answer is 0.125 hectares, or 0.125ha.

Détails de la réponse

To determine the expected maize plant population per hectare, we need to convert the given spacing from centimeters to meters, as the hectare is a unit of area in meters. 100cm x 50cm is equivalent to 1m x 0.5m. So the area required per maize plant is 0.5 square meters. Now, to find the number of plants per hectare (which is 10,000 square meters), we divide the total area by the area required per plant: 10,000 sq m / 0.5 sq m per plant = 20,000 plants per hectare. Therefore, the expected maize plant population per hectare is 20,000.

Détails de la réponse

Roundworms, also known as nematodes, can be found in the gut of livestock. These parasites live in the intestines of animals and feed on their nutrient-rich digested food. They can cause a range of health problems for the affected livestock, including reduced growth, weight loss, and diarrhea. To prevent the spread of roundworms, it is important to implement good hygiene and management practices on farms, such as regular deworming and keeping pasture areas clean.

Détails de la réponse

Détails de la réponse

The major storage pest of cereals in West Africa is the weevil. Weevils are small, brown beetles that lay their eggs in grain kernels. When the eggs hatch, the larvae feed on the grain, causing damage and reducing its quality. Weevils are particularly problematic in warm and humid environments, which are common in West Africa. They can infest a wide range of grains, including rice, maize, and millet. Infested grains can also attract other pests such as rats and birds, which can further damage the stored grains. Therefore, it is important to take measures to prevent and control weevil infestations in cereal storage in West Africa.

Détails de la réponse

(a) Identification of the implement

The implement illustrated is a cultivator (a tractor-drawn tine cultivator). It is recognised by its rigid frame carrying several curved tines that end in narrow shares, mounted on a wheeled frame with a hitch for attachment to a tractor.

(a)(ii) Names of the labelled parts

(b) One function of each labelled part

• I - Frame: It provides the rigid structure that holds and supports the tines, clamps and wheel firmly together.
• II - Clamp / bracket: It fastens each tine securely to the frame and allows the tine to be adjusted or replaced.
• III - Tine (shank): It penetrates the soil and carries the share, stirring and loosening the soil as the implement is drawn forward.
• IV - Share (point): It is the working edge that cuts into and breaks up the soil, uprooting weeds and forming a fine tilth.

(c) Farm operation

The cultivator is used for secondary tillage (cultivation): loosening and stirring the soil, breaking clods, uprooting and controlling weeds after primary ploughing, and preparing a fine seedbed.

(d) Two farm tools that perform similar functions

• West African hoe (used to loosen soil and weed)
• Hand fork / hand cultivator (used to stir and loosen soil)

(The harrow and the spade also perform comparable soil-loosening functions.)

(e) Three ways of maintaining the implement

1. Clean off soil and plant debris after every use and store it in a dry shed to prevent rust.
2. Oil or grease the wheel bearings and moving joints, and tighten any loose bolts and clamps regularly.
3. Sharpen blunt shares and replace worn or broken tines, and paint the frame to protect it from corrosion.

Détails de la réponse

(a) Four roles of government in agricultural development

(i) Pest and disease control

• Establishing quarantine services to check the movement and spread of pests and diseases.
• Providing and subsidising agrochemicals, spraying equipment and free vaccination, and carrying out research into control measures.

(ii) Marketing of agricultural produce

• Setting up marketing boards and providing storage facilities to reduce wastage.
• Building good roads for transport and guaranteeing stable, minimum prices for produce.

(b) Four general problems of the land tenure system in West Africa

1. Fragmentation of land into small, scattered units that cannot be mechanised.
2. Land held by inheritance and communal ownership discourages large-scale farming.
3. Difficulty in acquiring enough land for expansion, worsened by disputes and litigation.
4. Insecurity of tenure discourages tenants from making permanent improvements, and land is hard to use as loan collateral.

(c) Three farm machinery and three farm implements

Farm machinery:

1. Tractor
2. Combine harvester
3. Milking machine

Farm implements:

1. Plough
2. Harrow
3. Ridger

Détails de la réponse

The specimen shows a cocoa pod bearing dark, spreading rot patches, the symptoms of black pod disease.

(a)(i) Disease associated with the observed symptoms

Black pod disease of cocoa (caused by the fungus Phytophthora).

(a)(ii) Three ways of controlling the disease

1. Remove and destroy all infected pods promptly.
2. Prune the lower branches and canopy and weed regularly to reduce humidity around the trees.
3. Apply the recommended fungicide (for example a copper-based fungicide).

(b)(i) Three pests of cocoa

1. Cocoa capsids/mirids.
2. Mealy bugs.
3. Termites (stem borers and shield bugs also attack cocoa).

(b)(ii) Three ways of controlling the pests

1. Spray the trees with the appropriate insecticides.
2. Weed regularly and practise early harvesting to reduce pest breeding sites.
3. Use resistant crop varieties.

(c) Five factors to be considered in siting a crop farm

1. Soil fertility and soil type.
2. Topography of the land.
3. Accessibility and nearness to a good road.
4. Proximity to a source of water.
5. Proximity to the market (availability and cost of labour is also considered).

(d) Three ways of maintaining survey equipment

1. Clean or wash and dry it properly after use before storage.
2. Grease or oil the metal parts to prevent rust, and paint them when necessary.
3. Store it in a cool, dry place and keep the prismatic compass away from magnetic fields.

Détails de la réponse

(a) Crop classification based on life cycle: Crop | Classification based on life cycle ---|--- Mango | Perennial Rice | Annual Groundnut | Annual Cotton | Annual Pepper | Annual or Perennial (depending on variety) Soya bean | Annual Oil palm | Perennial Yam | Perennial Tomato | Annual Rubber | Perennial Ginger | Perennial Cocoa | Perennial Cowpea | Annual Carrot | Biennial (b) Four components of a typical soil and their percentage volume are: Soil component | Percentage volume ---|--- Mineral particles | 45% Organic matter | 5% Water | 25% Air | 25% (c) Three methods of applying inorganic fertilizers to the soil are: 1. Broadcasting: In this method, the fertilizer is uniformly spread over the soil surface. This can be done by hand or using a machine. Broadcasting is a quick and easy method but can result in uneven distribution of the fertilizer. 2. Banding: In this method, the fertilizer is applied in a concentrated band or row directly where the plant roots are located. This helps to ensure that the fertilizer is available to the plants when they need it. Banding requires more effort than broadcasting, but it can result in better fertilizer use efficiency. 3. Foliar application: In this method, the fertilizer is applied as a spray directly to the leaves of the plants. This is a quick and efficient way to provide nutrients to the plants, especially during periods of rapid growth or when the plants are under stress. However, foliar application is not a substitute for soil fertilization and should be used in combination with other methods.

Détails de la réponse

(a) Identification of the parasites

• I: Louse (an ecto-parasite)
• II: Tapeworm (an endo-parasite)

(b) Three external features of parasite I (Louse)

1. A distinct head, thorax and segmented abdomen.
2. Three pairs (six) of legs bearing sharp claws for clinging to the host.
3. A pair of antennae, a pair of compound eyes and biting-and-sucking mouthparts.

(c) Part of the host where parasite II (Tapeworm) is found

It is found in the small intestine of the host.

(c)(i) Four adaptive features of parasite II (Tapeworm) on its host

1. It possesses four suckers with which it attaches itself to the wall of the host's intestine.
2. It possesses two rows of hooks (rostellum) with which it fixes itself firmly in the intestine.
3. Its whole body is covered with a resistant cuticle that prevents it from being digested by the host's enzymes.
4. It has no digestive system of its own and absorbs digested food over its entire body, its great length providing a large surface area for absorption.

(c)(ii) Two intermediate hosts of parasite II (Tapeworm)

1. Cattle
2. Pigs

(d) Three effects of parasite I (Louse) on its host

1. It causes skin irritation, making the host restless, and leads to loss of hair or feathers.
2. It sucks the host's blood, leading to anaemia, loss of appetite and loss of weight.
3. The injuries it causes serve as sites for secondary infection, reducing livestock production and, in severe cases, causing death.

(e) Three effects of parasite II (Tapeworm) on its host

1. It robs the host of digested food, causing loss of weight, weakness and reduced production.
2. When present in large numbers it may block the intestine.
3. It releases toxins that make the host unthrifty and unproductive.

Détails de la réponse

(a)(i) Drainage is the removal of excess (gravitational) water from the surface and sub-surface of the soil so that the soil remains well aerated and workable.

(a)(ii) Reasons why waterlogged agricultural land should be drained:

1. To improve soil aeration so that plant roots and soil organisms can respire.
2. To raise soil temperature, which encourages seed germination and root growth.
3. To improve soil structure and workability, allowing tillage and machinery movement.
4. To remove toxic substances and prevent root-rot diseases, encouraging deeper rooting.

(b) Six factors affecting nutrient availability in the soil:

1. Soil pH (soil reaction).
2. Soil texture and structure.
3. Organic matter (humus) content.
4. Soil moisture content.
5. Soil temperature.
6. Activity of soil micro-organisms.

(c) Causative organisms of the crop diseases:

Détails de la réponse

(a) Completed weed table:

(b) Factors affecting land availability for agriculture:

(i) Physical factors:

1. Relief (topography) of the land.
2. Climate (rainfall and temperature).
3. Soil type and fertility.

(ii) Economic factors:

1. The land tenure system.
2. Availability of capital and the cost of land.
3. Access to markets and transport (and government policy).

(c) Four effects of pollution on agricultural lands and ponds:

1. It kills beneficial soil organisms and reduces soil fertility.
2. It contaminates the soil and water with toxic chemicals.
3. It kills fish and other aquatic life through oxygen depletion (eutrophication).
4. Toxins build up in crops and fish, making them harmful to consumers.

(d) Two ways of minimizing land and pond pollution:

1. Treat and properly dispose of industrial and domestic waste before it is discharged.
2. Use agrochemicals (fertilizers and pesticides) judiciously and only at recommended rates.

Détails de la réponse

(a) Explanation of terms

• Malnutrition: A condition that results from feeding an animal with a diet that is deficient, unbalanced, or in excess of one or more nutrients.
• Weaning: The gradual process of separating a young animal from its mother and changing it from a milk diet to solid feed.
• Heat period: The period (oestrus) during which the female animal is sexually receptive and ready to accept the male for mating.
• Candling: Passing an egg over or before a source of light in a dark room to examine its internal quality, fertility or stage of development.

(b) Maintenance ration and production ration distinguished

(c) Three effects of malnutrition on farm animals

1. It causes retarded or stunted growth.
2. It lowers productivity (less milk, eggs and meat) and causes poor reproduction.
3. It makes animals weak and more susceptible to diseases, and may cause death.

(d) Five effects of deforestation

1. It leads to soil erosion.
2. It causes loss of soil fertility.
3. It can lead to desertification.
4. It destroys the habitat of wildlife and reduces biodiversity.
5. It reduces rainfall and contributes to climate change and flooding.

Détails de la réponse

The three crops shown in the diagram are Cashew (nut with its swollen pseudo-fruit or cashew apple), Oil palm (fruit shown in cross-section revealing the mesocarp, shell and kernel) and Okro (the elongated ridged seed pod).

a) Method of propagating each crop

b) Three varieties of oil palm

• Dura (thick shell, thin mesocarp)
• Tenera (thin shell, thick mesocarp; the high-yielding commercial hybrid)
• Pisifera (shell-less, female-sterile; used as a pollen parent)

Other recognised types include Macrocarya (very thick shell).

c) Three diseases of okro

• Okro mosaic (leaf curl) disease, caused by a virus
• Cercospora leaf spot, caused by a fungus
• Fusarium wilt, caused by a soil-borne fungus

Powdery mildew and damping-off are also common okro diseases.

d) Three pre-planting operations in cultivating okro

• Land clearing to remove weeds, shrubs and debris from the site
• Ploughing, harrowing and ridging (tillage) to produce a fine, well-aerated seedbed
• Seed treatment/selection, that is selecting viable seeds and dressing them against soil pests and diseases before sowing

Other acceptable pre-planting operations are soil testing and the application of organic manure/basal fertiliser.

e) Three uses of cashew

• The cashew nut (kernel) is eaten as food, either raw, roasted or salted, and is a source of edible oil.
• The cashew apple (pseudo-fruit) is eaten fresh or processed into juice, jam and alcoholic/soft drinks.
• The nut-shell liquid is used industrially in the manufacture of paints, varnishes, brake linings and insecticides; the tree also yields timber and gum, and serves as a shade/ornamental and soil-conservation plant.

Détails de la réponse

(a) Calculations

Cost of tractor in 2000 = D 12,000.00; sold in 2009 for D 3,000.00.

(i) Useful life

(ii) Salvage value

The salvage value is the amount realised on disposal = D 3,000.00.

(iii) Total depreciation

(iv) Annual depreciation

(b) Description of terms

• (i) Demand schedule: A table showing the various quantities of a commodity that consumers are willing and able to buy at different prices over a period of time.
• (ii) Supply curve: A graph showing the relationship between price and quantity supplied; it slopes upward from left to right, showing that more is supplied at higher prices.

(c) Four agricultural extension agencies in West Africa

1. Agricultural Development Project (ADP)
2. Ministry of Agriculture
3. Agricultural research institutes
4. Farmers' cooperative societies

(d) Four ways soils are enriched with nitrogen

1. Growing leguminous crops that fix atmospheric nitrogen through Rhizobium bacteria.
2. Application of nitrogenous fertilizers.
3. Application of organic manure and green manuring.
4. Fixation of atmospheric nitrogen by lightning during rainfall.

Détails de la réponse

(a) Explanation of terms

• (i) Flushing: The practice of giving breeding females extra, high-quality feed a few weeks before and during mating to improve ovulation and conception.
• (ii) Castration: The removal or destruction of the testes of a male animal to prevent it from breeding.
• (iii) Culling: The removal of old, sick, unproductive or undesirable animals from a herd or flock.

(b) Two advantages of each

(i) Flushing

1. It increases the ovulation rate, giving more offspring (twinning).
2. It improves the body condition and conception rate of the breeding female.

(ii) Castration

1. It makes the animal docile and easy to handle.
2. It improves meat quality (tender meat without odour) and prevents unwanted mating.

(iii) Culling

1. It removes unproductive animals and cuts feeding costs.
2. It improves the general quality of the herd and provides income from animals sold.

(c) Two uses of each survey equipment

(i) Prismatic compass

1. To measure the bearings or directions of survey lines.
2. To measure horizontal angles during traversing.

(ii) Measuring tape

1. To measure distances and lengths on the field.
2. To measure the boundaries and offsets of a piece of land.

(d) Floriculture and aquaculture differentiated

Floriculture is the cultivation of flowers and ornamental plants, while aquaculture is the rearing or cultivation of aquatic organisms such as fish in water bodies or ponds.

Détails de la réponse

(a)(i) Intensive system and extensive system distinguished

(a)(ii) Five disadvantages of keeping livestock on free-range (extensive) system

1. Animals are exposed to attack by predators.
2. They are easily exposed to diseases and parasites.
3. Breeding cannot be controlled, leading to indiscriminate mating.
4. Growth is slow because feeding is inadequate and irregular.
5. Animals are difficult to supervise and are easily stolen.

(b) Six ways in which ornamental plants are important

1. They beautify and decorate the environment.
2. They provide shade.
3. They serve as windbreaks.
4. They help to check soil erosion.
5. They purify the air by giving out oxygen.
6. They are a source of income when sold and are used for landscaping.

Détails de la réponse

(a) Full meaning of the acronyms

• (i) WARDA: West Africa Rice Development Association
• (ii) IITA: International Institute of Tropical Agriculture
• (iii) FAO: Food and Agriculture Organization (of the United Nations)
• (iv) ILCA: International Livestock Centre for Africa

(b) Six ways agriculture benefits rural communities

1. It provides food for the rural people.
2. It provides employment and keeps people busy.
3. It is a source of income to the farmers.
4. It supplies raw materials for local rural industries.
5. It attracts the provision of infrastructure such as roads, water and electricity.
6. It reduces rural-to-urban migration by keeping people on the land.

(c) Four liming materials used in agriculture

1. Limestone (calcium carbonate)
2. Quicklime (calcium oxide)
3. Slaked or hydrated lime (calcium hydroxide)
4. Wood ash

(d) Four examples of sedimentary rocks

1. Limestone
2. Sandstone
3. Shale
4. Conglomerate

Détails de la réponse

(a) Depreciation in agricultural production

Depreciation is the gradual reduction or loss in the value of a durable (fixed) farm asset such as machinery or a building over time, due to wear and tear, age, or obsolescence.

(b) Distinguish between the pairs of terms

(i) Farm records and farm accounts

(ii) Credit and subsidy

(iii) Assets and liabilities

(c) Five problems of agricultural extension in West Africa

1. Inadequate funding of extension services.
2. Inadequate and poorly trained extension agents.
3. Poor transportation and inaccessible rural roads.
4. High level of illiteracy among farmers.
5. Wide farmer-to-agent ratio, so agents cannot reach all farmers.

(d) Five factors that affect the supply of cassava

1. Price of cassava.
2. Cost of production (inputs and labour).
3. Weather and climatic conditions.
4. Incidence of pests and diseases.
5. Government policy and the number of cassava farmers.

Détails de la réponse

The set-up is a soil sedimentation (mechanical analysis) experiment. Soil has been shaken with water in a tall transparent cylinder and left to stand. Because particles settle in order of size and density, the largest and heaviest fall first and the finest settle last, so the material grades from coarse at the bottom to fine at the top, with organic matter floating on the water surface.

(a)(i) Aim of the experiment

To separate a soil sample into its constituent fractions (gravel, sand, silt, clay and organic matter) according to particle size, and so to determine the texture and composition of the soil by sedimentation.

(a)(ii) Parts labelled I and II

The pointers pick out the two fine bands lying just under the floating organic matter and the clear water, above the coarser sand and gravel at the base. In a settled column the finest fraction rests highest:

• I = Clay (the finest particles, still partly in suspension, forming the uppermost, densely stippled band of settled sediment just below the water).
• II = Silt (the next, slightly coarser band lying directly beneath the clay).

For orientation: the wispy material floating on the surface is decayed organic matter (humus), and below silt lie sand and then gravel/stones at the very base.

(b) How the experiment is carried out

1. Take a sample of dry, crushed soil and pick out large roots and stones.
2. Put the soil into a tall transparent glass jar or measuring cylinder until it is about one-third full.
3. Add clean water (and a little dispersing agent such as sodium carbonate or caustic soda) until the jar is about three-quarters full.
4. Cover the mouth and shake vigorously so that all the clods break up and every particle is suspended in the water.
5. Stand the jar on a level bench and leave it undisturbed for about an hour (or longer).
6. Observe the layers as they settle: gravel and stones at the bottom, then sand, then silt, then clay, with humus floating on top and the water clearing above.
7. Measure the depth of each layer and express it as a percentage of the total settled soil to estimate the proportion of each fraction. For example, if sand is \(4\ \text{cm}\) of a total \(10\ \text{cm}\) of settled soil, \(\dfrac{4}{10}\times 100\% = 40\%\).

(c) Four properties of sandy soils

1. Large particles with wide pore spaces, giving very good aeration and free (rapid) drainage.
2. Low water-holding capacity, so the soil dries out quickly and needs frequent watering.
3. Poor in plant nutrients and low in humus, and nutrients are easily leached (washed) out.
4. Light, loose and gritty; it warms up quickly and is easy to till.

(d) Test for soil acidity using litmus paper

1. Put a little of the soil sample into a clean test tube or beaker.
2. Add distilled (or rain) water, stir well to make a suspension, and allow it to settle so a clear solution forms above the soil.
3. Dip a strip of blue litmus paper into the clear liquid; test a fresh portion with red litmus paper as well.
4. If the blue litmus paper turns red, the soil is acidic. If red litmus turns blue, the soil is alkaline (basic); if neither paper changes colour, the soil is neutral.

Détails de la réponse

(a) Spacing and thinning distinguished

(b) Cultivation of oil palm

• (i) Botanical name: Elaeis guineensis.
• (ii) Two varieties: Dura and Tenera.
• (iii) Method of propagation: By seed (sexual). Pre-germinated seeds are raised in a pre-nursery and nursery before the seedlings are transplanted to the field.
• (iv) Soil requirement: Deep, well-drained, fertile loamy soil that is rich in organic matter and slightly acidic.
• (v) Spacing on the field: About 9 m by 9 m triangular (giving roughly 143 palms per hectare).
• (vi) Diseases: Blast disease, freckle/leaf spot, and vascular (Fusarium) wilt.

(c) Six ways forest resources are important to the economy of West Africa

1. They supply timber for building and furniture.
2. They provide fuel wood and charcoal.
3. They supply raw materials for industries (pulp, paper).
4. They provide employment and income.
5. They are a source of medicinal plants and food (fruits, bush meat).
6. They earn foreign exchange through export of forest products.

(d) Apiculture

Apiculture is the practice of keeping and rearing honey bees in hives for the production of honey and beeswax.