WAEC SSCE - Agricultural Science - 2017

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Mulching is an example of a cultural weed control method. Mulching is the practice of placing a layer of organic material, such as leaves or straw, over the soil surface to suppress weed growth. The mulch acts as a physical barrier, preventing light from reaching the weed seeds and preventing them from germinating. Additionally, mulch can help retain moisture in the soil and suppress weeds by suppressing the growth of weed seeds that are already present in the soil. This is an example of a cultural weed control method because it does not rely on the use of chemicals or other external inputs and instead relies on natural processes to control weed growth.

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Akọwa Nkọwa

The social factor that affects land availability and use is the culture of the people. Culture refers to the way of life of a group of people, including their beliefs, customs, and traditions. Different cultures have different practices regarding land ownership, land use, and land distribution. For example, in some cultures, land is communal and is owned by the community as a whole, while in other cultures, land is privately owned and passed down through families. These cultural practices can affect the availability of land for different uses such as agriculture, housing, and recreation. In some cultures, land is primarily used for agricultural purposes, while in others, it may be used for commercial or residential purposes. The culture of the people can also influence the types of crops that are grown, the methods of farming that are used, and the ways in which the land is managed and conserved. Therefore, understanding the cultural practices of a community is crucial in determining how land is used and made available for different purposes.

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At a price of Le 1,000.00, the demand for mangoes is 60 baskets while the supply is only 10 baskets. Therefore, the excess demand over supply of mangoes is 50 baskets. Excess demand occurs when the quantity of a good demanded by consumers exceeds the quantity supplied by producers at a particular price level. In this case, the demand for mangoes at a price of Le 1,000.00 is greater than the amount of mangoes that suppliers are willing and able to sell at that price, resulting in a shortage or excess demand of 50 baskets. This situation can lead to higher prices as consumers are willing to pay more to obtain the desired quantity of mangoes, and producers may increase supply to take advantage of the higher prices. Conversely, if the excess demand persists, some consumers may switch to other substitute fruits, and some producers may switch to producing other fruits, leading to a decrease in the excess demand.

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A raw material that could be obtained from the forest is honey. Honey is a natural sweetener made by bees from flower nectar. Bees collect the nectar from flowers in the forest and then process it into honey. This means that honey is a product that can be obtained from the forest. Margarine and butter, on the other hand, are made from dairy products which are obtained from cows that are usually raised in farms. Mutton is meat from sheep which are also typically raised in farms rather than the forest.

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Akọwa Nkọwa

Akọwa Nkọwa

By-products of livestock used as feed ingredients in poultry ration include blood and bones, feathers and fur, and skin and bones. Blood and bones are a rich source of protein, minerals, and amino acids that are essential for the growth and development of poultry. They are usually obtained from slaughterhouses and are processed into bone meal and blood meal, which are then added to poultry feed. Feathers and fur are also a good source of protein and can be hydrolyzed to release amino acids that can be absorbed by poultry. They are usually obtained from poultry processing plants and are processed into feather meal or poultry by-product meal, which are then added to poultry feed. Skin and bones are another by-product of livestock that can be used as feed ingredients in poultry ration. They are usually obtained from meat processing plants and are processed into meat and bone meal, which are then added to poultry feed. Using these by-products in poultry feed not only helps to reduce waste but also provides a cost-effective source of nutrients for poultry. It also helps to reduce the environmental impact of livestock production by diverting these by-products from landfills and turning them into valuable feed ingredients.

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The statement that is not correct about soil texture is: "Fine-textured soils are warm soils and coarse-textured soils are cool soils." Soil texture refers to the composition of soil in terms of the relative proportion of sand, silt, and clay particles. The four options are related to different properties of soil texture. The first statement is correct; soils with fine particles have a higher water holding capacity than coarse soils. This is because fine-textured soils have more surface area per unit of volume, which allows them to hold more water. The third statement is also incorrect. Leaching is the process by which water moves through the soil and carries nutrients with it. Coarse-textured soils have larger pores, which allow water to move through them more quickly, resulting in a greater loss of nutrients through leaching than in fine-textured soils. The fourth statement is correct; fine-textured soils have a higher nutrient holding capacity than coarse-textured soils. This is because the smaller particles in fine-textured soils have more surface area to which nutrients can attach. In contrast, the second statement is the one that is not correct. Soil texture does not necessarily determine the temperature of the soil. Soil temperature is influenced by many factors, including climate, vegetation cover, and the depth of the soil. Soil color, organic matter content, and moisture also affect soil temperature. Therefore, it is incorrect to assume that fine-textured soils are always warm and coarse-textured soils are always cool.

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The pair of diseases that attack coffee plants is rust and leaf spot. Rust is a fungal disease that appears as yellow-orange spots on the underside of coffee leaves, which can then spread to the upper side of the leaves. Rust can weaken coffee plants and reduce the yield of coffee cherries. Leaf spot is another fungal disease that affects coffee plants. It causes dark spots on the leaves, which can turn yellow or brown over time. Leaf spot can also weaken the coffee plant and reduce the yield of coffee cherries. Mosaic and smut are diseases that do not typically affect coffee plants. Mosaic is a viral disease that affects many crops, including tobacco and maize. Smut is a fungal disease that commonly affects corn, wheat, and sugarcane. Ridge is a bacterial disease that can affect potato plants. Therefore, in summary, the pair of diseases that attack coffee plants are rust and leaf spot.

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The statement that is not a problem associated with land tenure system through inheritance is "Family members have right to free use of land." Explanation: Land tenure system through inheritance has its own set of problems, but the right to free use of land by family members is not one of them. In fact, it is a common practice in many societies that family members have free use of the land that they inherit. The other three options are problems associated with land tenure system through inheritance. Family members having small land holdings can result in fragmentation of land, which reduces the efficiency of farming. Non-family members not being able to inherit land can lead to social inequality and exclusion of certain groups. Farm mechanization being restricted can limit the use of modern farming technologies and decrease productivity.

Akọwa Nkọwa

To determine the area of a farmland in hectares, we first need to calculate its area in square meters. A farmland that measures 50m x 50m has an area of 50m x 50m = 2500m^2. Next, we need to convert square meters to hectares. One hectare is equal to 10,000 square meters. To convert square meters to hectares, we divide the number of square meters by 10,000. So, 2500m^2 / 10,000 = 0.25 hectares. Therefore, the area of the farmland is 0.25 hectares.

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Akọwa Nkọwa

Akọwa Nkọwa

The farming method you're describing is called "crop rotation". It's when farmers grow different types of crops in a specific order, one after the other, on the same piece of land. The idea behind crop rotation is that different crops have different nutrient needs and can also leave different nutrients in the soil. So, by alternating crops, farmers can avoid depleting the soil of specific nutrients and also help to control pests and diseases. For example, one year a farmer may grow corn, which is a heavy feeder that depletes the soil of nitrogen. The next year, they might grow beans, which actually adds nitrogen back to the soil. Then, the following year, they could grow wheat or another crop that doesn't require as much nitrogen. This way, the soil remains healthy and productive. Crop rotation has been practiced for thousands of years and is still used by farmers today as a sustainable and effective farming method.

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To determine the spacing between stands to obtain a plant population of 40,000 plants per hectare, we first need to understand the definition of plant population. Plant population is the number of plants per unit area. In this case, the desired plant population is 40,000 plants per hectare. If the rows of crops are spaced 1.0m apart with one seed sown per stand, then the distance between the plants within a row is not important for determining the plant population per hectare. We can calculate the number of plants per hectare as follows: 40,000 plants/ha = (10,000 m²/ha) x (1 row/1.0 m) x (1 stand/x) Solving for x, we get: x = (10,000 m²/ha) / (40,000 plants/ha) = 0.25 m/stand Therefore, the spacing between stands required to obtain a plant population of 40,000 plants per hectare is 0.25 meters. Hence, the correct answer is 0.25m.

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Akọwa Nkọwa

Based on the digestive tract diagram provided, the farm animal being referred to is a pig. Pigs have a very unique digestive system that is similar to humans in many ways. Their digestive system is divided into several parts including the mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus. In the diagram, you can see that the digestive tract of the animal has a stomach with four compartments, which is characteristic of pigs. This type of stomach is necessary for breaking down the tough fibrous materials found in plants, which makes up a significant portion of a pig's diet. Furthermore, the length of the small intestine in the pig is relatively long, which is necessary for extracting nutrients from the food that is consumed. Pigs are omnivorous animals, which means that they eat both plants and animals, and their digestive system has evolved to be able to handle a wide range of different types of food. In summary, the digestive tract diagram provided belongs to a pig because of its unique four-chambered stomach and relatively long small intestine, which are essential for breaking down plant materials and extracting nutrients from the food that they consume.

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The part labelled III in the diagram refers to the small intestine, which is responsible for the majority of nutrient absorption. The small intestine produces several enzymes to help digest food, including amylase, lipase, and trypsin. Pepsin is not produced in the small intestine (part III). Pepsin is actually produced in the stomach (part II) and is responsible for breaking down proteins into smaller peptides. Once the food is mixed with gastric juices in the stomach, it enters the small intestine where other enzymes take over the process of digestion and absorption of nutrients. Therefore, the correct answer is Pepsin.

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Flood irrigation is used for the cultivation of crops like swamp rice. This type of irrigation involves flooding a field with water and allowing it to slowly drain. The field stays submerged for a certain period of time, providing water and nutrients to the rice plants. This method is commonly used in low-lying areas where rice is grown and water is abundant. The flooded field also helps to control weeds and pests, making it an effective and efficient way to grow rice in these conditions.

Akọwa Nkọwa

The climatic condition that does not affect agricultural production is topography. Topography refers to the physical features of the land, such as its elevation, slope, and shape, which can affect factors such as water drainage and soil quality. While topography can have indirect effects on agriculture, such as by influencing the amount and distribution of rainfall, it is not a direct climatic factor like rainfall, relative humidity, and temperature. Rainfall is important because it provides the necessary water for crops to grow, while relative humidity and temperature affect the rate of evaporation and transpiration, which determine the water requirements of crops. Extreme temperatures and low relative humidity can lead to water stress and reduce crop yields. Therefore, farmers need to understand the climatic conditions in their region to make informed decisions about what crops to plant, when to plant them, and how to manage them throughout the growing season.

Akọwa Nkọwa

Imported plants are expected to go through a process called quarantine. This means that they are kept separate from other plants for a certain period of time to make sure that they are not carrying any diseases or pests that could harm other plants in the local environment. This helps to protect the local plant species and prevent the spread of any harmful organisms.

Akọwa Nkọwa

The parasite illustrated above obtains nutrients from the host through diffusion. Diffusion is the movement of molecules from an area of high concentration to an area of low concentration. In this case, the parasite absorbs nutrients from the host's body fluids by diffusing across the membrane that separates the parasite from the host. The host's body fluids have a higher concentration of nutrients than the parasite, so the nutrients move from the host to the parasite by diffusion. This allows the parasite to obtain the nutrients it needs to survive and reproduce. Osmosis and capillarity are the movements of fluids, and egestion is the elimination of waste from the body, so they are not the correct answer in this context.

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The part labelled I is the "scolex", the part labelled II is the "rostellum", and the part labelled III is the "sucker". Together, these parts form the "head" or anterior end of the parasite, known as the "scolex". The scolex is the part of the parasite that attaches to the host's intestinal wall, while the rostellum and sucker are specialized structures that help the parasite attach and feed on the host's blood or nutrients. The proglottide, on the other hand, is a segment of the tapeworm's body that contains reproductive organs and develops behind the scolex.

Akọwa Nkọwa

The demand for agricultural produce is generally considered to be inelastic, which means that a change in price does not greatly affect the quantity demanded. This is because, in many cases, people need to buy food regardless of its price, and they may not have many alternative options. For example, if the price of wheat increases, people may still need to buy bread, so they will continue to purchase wheat even though it is now more expensive.

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The presence of excess water in the colloids of soil particles is known as waterlogging. When soil has too much water, it can't drain properly, and the excess water fills up the spaces in the soil between particles. This can lead to a lack of oxygen in the soil, which can harm plants and other organisms that depend on the soil. Waterlogging can happen due to factors like heavy rainfall, poor drainage, or a high water table. It's important to manage waterlogging to maintain healthy soil and support healthy plant growth.

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The agent that is not associated with chemical weathering is pressure. Chemical weathering is the breakdown or decomposition of rocks and minerals caused by chemical reactions with substances such as water, oxygen, and acids. Oxidation is the process where oxygen reacts with a substance and changes its chemical composition, resulting in the breakdown of rocks and minerals. Hydrolysis is the process where water reacts with minerals and rocks and causes them to break down. Carbonation is a chemical reaction where carbon dioxide reacts with water to form carbonic acid, which can dissolve minerals in rocks, resulting in their breakdown. However, pressure is a physical weathering agent that causes rocks to break down through physical forces, such as compression or tension, rather than chemical reactions. Examples of physical weathering agents include water, wind, and ice. These agents can cause rocks to break down into smaller pieces without changing their chemical composition. Therefore, pressure is not associated with chemical weathering, but rather with physical weathering.

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The branch of agriculture which deals with the production of fruits is called pomology. Pomology is the study and cultivation of fruit trees and fruits including apples, pears, peaches, plums, cherries, and citrus. Pomologists work to improve fruit quality, yield, and disease resistance. They also develop new varieties of fruit trees that are more resistant to pests and diseases, and can tolerate different climates and soil types. In summary, pomology is the study and cultivation of fruits, and it is a branch of agriculture that focuses on the production of fruit crops.

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The agent that is not involved in agricultural marketing is money lenders. Agricultural marketing refers to the various activities involved in the buying, selling, and distribution of agricultural products from the point of production to the point of consumption. Commodity boards, retailers, and middlemen are all agents involved in agricultural marketing. Commodity boards are organizations that are set up by the government or private sector to regulate the production, marketing, and distribution of agricultural commodities. They help to ensure that farmers get fair prices for their products and that consumers get quality products. Retailers are businesses that sell agricultural products directly to consumers. They include supermarkets, grocery stores, and farmers' markets. Retailers buy products from farmers and middlemen and sell them to consumers. Middlemen are intermediaries who help to connect farmers with buyers. They include wholesalers, brokers, and commission agents. They buy products from farmers and sell them to retailers or processors. Money lenders, on the other hand, are not involved in agricultural marketing. Money lenders provide loans to farmers, but they do not participate in the buying, selling, or distribution of agricultural products.

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The practice of mating closely related animals is called in-breeding. In-breeding is when animals who are closely related to each other, such as siblings or parent-offspring, are bred together. This can increase the likelihood of genetic disorders and other health problems in offspring, as well as reduce overall genetic diversity. It is generally not recommended in animal breeding programs and is only done in certain circumstances, such as when attempting to preserve a rare breed.

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The deficiency symptom that can inhibit both root and fruit formation is a lack of phosphorus in the plant's soil. Phosphorus is an essential nutrient that plays a vital role in a plant's growth and development. It helps in the formation of strong roots and stimulates the growth of fruits and flowers. When a plant lacks sufficient phosphorus, it can lead to stunted root growth and poor fruit development. In contrast, nitrogen is required for leaf and stem growth, while iron is necessary for chlorophyll synthesis, which gives leaves their green color. Chlorine is important for photosynthesis, but its deficiency symptoms typically manifest as yellowing or wilting of leaves, rather than affecting root and fruit formation.

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To determine the laying percentage of the birds, we need to find the proportion of eggs laid by each bird in a day. If we divide the total number of eggs collected (800) by the number of birds (1,200), we get the average number of eggs per bird in a day: 800 eggs ÷ 1,200 birds = 0.67 eggs per bird To convert this to a percentage, we can multiply by 100: 0.67 eggs per bird × 100 = 67% laying percentage Therefore, the laying percentage of the birds is 67%.

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Heat treatment of oil palm seeds before sowing is known to break the embryo dormancy. Dormancy is a period of inhibited growth that helps the seed to survive adverse environmental conditions. However, it can also prevent the seed from germinating even under favorable conditions. Applying heat to the seed allows it to overcome this dormancy and initiate growth. Breaking the dormancy allows the embryo to start using the stored nutrients in the seed, mobilizing them for growth. This helps in the early establishment of the seedling and improves its chances of survival. Heat treatment can also help to improve disease resistance by killing or removing pathogens that may be present on the seed surface or inside the seed. However, heat treatment does not harden the mesocarp, which is the fleshy outer layer of the fruit surrounding the seed. The mesocarp does not play a significant role in seed germination or early seedling growth.

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Land use for agriculture in West Africa is influenced by several factors, including topography, population density, fallowing, and climatic conditions. However, one of these factors does not have a significant influence on land use for agriculture in West Africa, and that is "fallowing." Fallowing refers to the practice of leaving land uncultivated for a period of time to allow it to recover from the depletion of nutrients caused by farming activities. While fallowing can be an essential practice for maintaining soil fertility, it is not a significant factor in determining land use for agriculture in West Africa. On the other hand, topography, population density, and climatic conditions all have a significant influence on land use for agriculture in West Africa. Topography, or the physical features of the land, can impact the type of crops that can be grown and the methods used to cultivate them. Population density affects the availability of land for farming, while climatic conditions such as rainfall and temperature can determine the types of crops that can be grown and the timing of planting and harvesting.

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The correct sequence of pre-planting operations is: clearing, stumping, ploughing, and harrowing. 1. Clearing: This step involves removing any weeds, bushes, or trees from the area where the crops will be planted. This ensures that the soil is free of any obstacles that might interfere with the planting process. 2. Stumping: After clearing, the remaining tree stumps are removed from the soil using a stump grinder or other methods. This helps to level the field and prepare the soil for the next step. 3. Ploughing: In this step, the soil is turned over using a plough. This helps to break up the soil and mix in any organic matter, such as compost or manure, to improve soil fertility. 4. Harrowing: The final step involves using a harrow to break up any clumps of soil, creating a smooth and even surface for planting. This also helps to mix in any added fertilizer, ensuring that it is evenly distributed throughout the soil. By following this sequence, the soil is properly prepared for planting, providing the best conditions for crop growth and development.

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The practice that is not a way of maintaining ornamental plants is "harvesting." Harvesting is the process of collecting crops from plants after they have matured. However, ornamental plants are usually grown for their beauty and not for consumption. Therefore, there is usually no need to harvest them. On the other hand, pruning is important for the overall health and appearance of ornamental plants. Weeding is necessary to remove unwanted plants that compete for resources and nutrients with ornamental plants. Watering is important to keep the plants hydrated, and it is essential to the survival and growth of ornamental plants. Therefore, the correct answer is "harvesting."

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Carbon dioxide is used by crops for photosynthesis. Photosynthesis is the process by which plants use sunlight, water, and carbon dioxide to produce energy in the form of glucose and release oxygen into the atmosphere. The carbon dioxide taken in by the plants is used to build the organic molecules that make up their structure and energy reserves, such as sugars and starches. In this way, plants serve as carbon sinks, removing carbon dioxide from the atmosphere and incorporating it into their biomass. Therefore, carbon dioxide plays a crucial role in the growth and survival of crops and other plants.

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The equipment that could be used in place of the equipment labelled II for the management of chicks is the electric bulb. The electric bulb can be used to provide heat to the chicks, which is essential for their survival and growth during the first few weeks of their life. Chicks need a warm environment, and a temperature of around 95-100°F is required for the first week of their life. The electric bulb can provide this heat and keep the chicks warm and comfortable. On the other hand, the incubator is used for hatching eggs, the feeder is used for providing feed to the chicks, and the egg candler is used to check the quality of eggs by looking inside them with a bright light. Therefore, in summary, the electric bulb is the equipment that can be used in place of equipment II for the management of chicks.

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Akọwa Nkọwa

Farmers use predators to control pests. Predators are animals that naturally eat or kill other animals, and when they are introduced into a crop or garden, they can help to reduce the population of pests that can damage or destroy the plants. This approach is a form of biological pest control, which aims to use natural predators or other living organisms to control pests, rather than relying on chemical pesticides that can harm the environment and human health. By using predators, farmers can reduce their dependence on pesticides and create a more sustainable and eco-friendly approach to farming.

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Akọwa Nkọwa

(a) Economic concepts:

• (i) Scarcity: Scarcity means that the resources (land, labour, capital) available to satisfy people's wants are limited relative to the unlimited wants. Because resources are limited, choices must be made.
• (ii) Scale of preference: A scale of preference is a list of a person's wants arranged in order of their importance, with the most pressing want at the top, so that the most urgent needs are satisfied first with the limited resources.

(b) Four reasons why agricultural insurance is important:

• It pays compensation to the farmer for losses from fire, flood, drought, pests or disease.
• It gives the farmer confidence to invest and expand the farm.
• It makes it easier for the farmer to obtain loans, since the insured farm is used as security.
• It spreads/reduces the risk of farming and keeps the farmer in business after a disaster.

(c) Five fishery regulations in West Africa:

• Use of nets with the approved (large) mesh size to protect young fish.
• Ban on the use of poisons, chemicals and explosives in fishing.
• Closed seasons during which fishing is prohibited to allow fish to breed.
• Licensing/registration of fishermen and fishing boats.
• Prohibition of catching immature/undersized fish and fishing in restricted zones.

(d) Five reasons why beekeeping is important:

• It produces honey used as food and medicine.
• It produces beeswax used in industry (candles, cosmetics, polishes).
• Bees pollinate crops and so increase crop yield.
• It provides income and employment to farmers.
• It requires little land and capital to start.

Akọwa Nkọwa

(a) Maize smut disease

(i) Causal organism:
A fungus, Ustilago maydis (also known as Ustilago zeae).

(ii) Mode of transmission:
The disease is transmitted mainly by wind or air-borne spores which are deposited on maize leaves, ears, tassels or other parts of susceptible plants. Spores may also survive in infected crop residues and soil.

(iii) Symptoms:

• Large galls or swellings occur on the ears/cobs, leaves, stems and tassels.
• The galls later burst and release black, powdery masses of spores; affected plants may become stunted or dwarfish.

(iv) Cultural control measures:

• Use clean, certified disease-free seeds or resistant varieties.
• Uproot and burn infected plants or galls and practise crop rotation.

(b) Four forest management practices in West Africa

• Afforestation and reforestation.
• Natural or artificial regeneration of forest trees.
• Selective exploitation or controlled felling of mature trees.
• Taungya system.

(c)(i) Four classes of farm animals based on their uses and (ii) one example of each

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(a) Anthrax disease:

• (i) Causal organism: A bacterium, Bacillus anthracis.
• (ii) Mode of transmission: By ingestion of feed, water or pasture contaminated with the spores; through contact with infected animals, their carcasses or products; and through wounds and biting insects.
• (iii) Two symptoms:
  • Sudden death, often with high fever before death.
  • Discharge of dark, tarry, unclotted blood from natural body openings (nose, mouth, anus) and swellings on the body.
• (iv) Two prevention and control measures:
  • Vaccinate healthy animals regularly against anthrax.
  • Burn or bury deeply (with quicklime) the carcasses of infected animals; never open them, and isolate/quarantine affected herds.

(b)(i) Four sources of plant protein in livestock feeds:

• Groundnut cake
• Soya bean meal
• Palm kernel cake
• Cottonseed cake (or brewer's dried grain)

(b)(ii) Three examples of forage legumes in West African rangelands:

• Centrosema (Centrosema pubescens)
• Stylosanthes (Stylosanthes gracilis)
• Pueraria (Pueraria phaseoloides)

(c) Five characteristics of labour as a factor of agricultural production:

• Labour is human effort (physical and mental) used in production.
• Labour cannot be separated from the labourer.
• Labour is perishable; time lost when a worker is idle cannot be recovered.
• Labour is mobile; it can move from one place or job to another.
• Labour has feelings and needs rewards (wages), rest and good treatment to work well; its supply and efficiency vary.

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(a) Water cycle

(b) Deficiency symptoms of phosphorus in crops

• Stunted growth and poorly developed roots.
• Leaves, especially older leaves, develop a purplish or reddish coloration, usually beginning from the tips.
• Flowering, seed formation and maturity may be delayed or reduced.

(c) Classification of insect pests according to mode of feeding

Biting and chewing pests	Piercing and sucking pests	Boring pests
Locust Armyworm	Scale insect Cotton stainer Green spider mites Thrips Capsids	Weevil Earworm Yam beetle

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(a) Five non-government agricultural organizations in West Africa:

• West Africa Rice Development Agency (WARDA/AfricaRice)
• International Institute of Tropical Agriculture (IITA)
• Food and Agriculture Organization (FAO)
• Sasakawa Global 2000
• International Fund for Agricultural Development (IFAD)

(b) Four ways in which agriculture and industry are interrelated:

• Agriculture supplies raw materials (cotton, cocoa, oil palm, rubber) to industries for processing.
• Industry supplies farm inputs (fertilisers, machines, chemicals) to agriculture.
• Agriculture provides food for industrial workers.
• Both provide market for each other's products and provide employment and income.

(c) One function of each part of a disc plough:

(d) Four disadvantages of animal power:

• Animals are slow and cover only a small area of land per day.
• They tire easily and cannot work for long hours.
• They need feeding, housing and veterinary care, which cost money and time.
• They can be affected by diseases and may die, and cannot be used on all types of land.

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(a) Five factors to consider in choosing an irrigation system in West Africa:

• The source and availability of water (rivers, dams, boreholes).
• The topography (slope and nature) of the land.
• The type of soil and its infiltration/drainage.
• The type of crop to be grown and its water requirement.
• The cost of installation and the capital available to the farmer.

(b) Four problems associated with irrigation in West Africa:

• High cost of installing and maintaining the system.
• Salinization/salt build-up and water-logging of the soil.
• Inadequate/irregular water supply and silting of channels.
• Spread of water-borne diseases such as bilharzia and pests/weeds.

(c) Area of the farmland in hectares:

Convert the length to metres: \(0.4\ \text{km} = 0.4 \times 1000 = 400\ \text{m}\).

\[ \text{Area} = \text{length} \times \text{breadth} = 400\ \text{m} \times 2400\ \text{m} = 960{,}000\ \text{m}^2 \]

Since \(1\ \text{hectare} = 10{,}000\ \text{m}^2\):

\[ \text{Area} = \frac{960{,}000}{10{,}000} = 96\ \text{hectares} \]

(d) Tillage implements:

• One primary tillage implement: Plough (disc or mould-board plough).
• Three secondary tillage implements: Harrow, ridger and cultivator.