WAEC SSCE - Agricultural Science - 2020

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The crop that is dicotyledonous from the given options is Vigna unguiculata, also known as cowpea. Dicotyledonous plants, also called dicots, are plants that have seeds with two cotyledons or embryonic leaves. These plants generally have broad leaves with veins that are arranged in a branched or net-like pattern. On the other hand, monocotyledonous plants, or monocots, have seeds with a single cotyledon or embryonic leaf. These plants typically have long, narrow leaves with veins that are parallel to each other. Among the given options, Zea mays (corn), Oryza sativa (rice), and Elaeis guineensis (oil palm) are monocotyledonous plants, while Vigna unguiculata (cowpea) is a dicotyledonous plant. Cowpea is an important legume crop that is widely cultivated for its high protein content and ability to fix nitrogen in the soil. It is commonly grown in tropical and subtropical regions of the world and is used for food, feed, and forage purposes.

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Digestion in ruminants, such as cows and sheep, is mainly microbial and enzymatic. Ruminants have a four-chambered stomach that allows them to digest tough plant materials like cellulose. The first chamber, the rumen, is where microbial fermentation occurs. Bacteria, protozoa, and fungi in the rumen break down the cellulose and other complex carbohydrates in the food into simpler compounds that can be absorbed by the animal. Enzymes produced by the animal and microbes in the rumen also break down proteins and fats into simpler compounds that can be absorbed. The rumen also acts as a storage chamber, allowing the animal to regurgitate and re-chew their food (mastication) before swallowing it again for further digestion. The other three chambers of the ruminant stomach (reticulum, omasum, and abomasum) continue the enzymatic and microbial breakdown of the food before it moves into the small intestine for absorption of nutrients. In summary, digestion in ruminants is mainly microbial and enzymatic. The rumen, with its complex microbial community, plays a crucial role in breaking down complex carbohydrates in the diet, while enzymatic digestion of proteins and fats occurs throughout the digestive tract.

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The yield of cowpea from a farm depends on the area of the farm and the yield per hectare. Given that the yield of cowpea is 750kg per hectare, we can calculate the total yield from a 20-hectare farm by multiplying the yield per hectare by the total area of the farm. Therefore, the yield of cowpea from a 20-hectare farm would be: Yield = Yield per hectare × Area of the farm Yield = 750kg/hectare × 20 hectares Yield = 15,000kg So, the answer is 15,000kg.

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The illustrated equipment is called a ranging pole. A ranging pole is a long, straight stick or rod used to measure distances or to determine the position of something. It can be used in surveying, construction, or any other field where precise measurements are needed. The pole is held vertically and its shadow is used to determine the angle of the sun or other reference points, allowing the user to make accurate measurements. The ranging pole is a simple and effective tool that has been used for centuries to help people measure and map the world around them.

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To calculate the area of the farmland, we need to know the dimensions of the land. However, as we are only given the area of the land in hectares, we cannot determine the length and width of the land directly. Hectares are a unit of area commonly used to measure land. One hectare is equal to 10,000 square meters or approximately 2.47 acres. Therefore, to calculate the area of the farmland in square meters, we can multiply the given area in hectares by 10,000. For example, if the given area is 0.32 hectares, we can calculate the area in square meters as follows: Area in square meters = 0.32 hectares x 10,000 square meters/hectare Area in square meters = 3,200 square meters Similarly, we can calculate the area in square meters for each given option and compare them to determine which one is the largest. The largest area in square meters corresponds to the largest option in hectares.

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The part labeled "C" in a graph is the "equilibrium point". This is where the quantity of a good or service that consumers are willing and able to buy (i.e. the quantity demanded) is equal to the quantity that producers are willing and able to sell (i.e. the quantity supplied). In other words, it's the point where there is balance between the amount of a product that is being bought and sold, and there is no surplus or shortage.

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NPK 5-10-15 is a type of fertilizer that contains three important nutrients for plant growth: nitrogen (N), phosphorus (P), and potassium (K). The three numbers on the label, separated by hyphens, indicate the percentage of each nutrient present in the fertilizer. In this case, NPK 5-10-15 means that the fertilizer contains 5% nitrogen, 10% phosphorus, and 15% potassium. To determine the ratio of these nutrients, we need to divide each percentage by the lowest percentage to get the simplest whole number ratio. In this case, the lowest percentage is 5%, so we divide each percentage by 5%. 5% nitrogen ÷ 5% = 1 10% phosphorus ÷ 5% = 2 15% potassium ÷ 5% = 3 Therefore, the ratio of nutrients in NPK 5-10-15 is 1:2:3, which means that for every 1 part of nitrogen, there are 2 parts of phosphorus and 3 parts of potassium in the fertilizer. This ratio is important because different plants require different amounts of nutrients, and fertilizers with different ratios can be used to target specific nutrient needs.

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Teak is the tree species that is suitable for making electric poles. Teak wood is known for its strength, durability, and resistance to decay and insects. These qualities make it a popular choice for outdoor structures such as electric poles. The wood is also able to withstand extreme weather conditions, making it a reliable option for supporting power lines. Additionally, teak is relatively easy to work with, making it a popular choice for construction projects. So, if you need to choose a tree species for making electric poles, teak is a great option to consider.

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To find the percentage change in quantity demanded, we need to calculate the difference between the initial quantity demanded and the final quantity demanded, divide that difference by the initial quantity demanded, and then multiply the result by 100%. The initial quantity demanded is 12,000kg, and the final quantity demanded is 8,000kg. Therefore, the difference is: 12,000kg - 8,000kg = 4,000kg To calculate the percentage change, we divide the difference by the initial quantity and multiply by 100%: (4,000kg / 12,000kg) x 100% = 33.33% Therefore, the answer is 33%. The percentage change in quantity demanded is a decrease of 33.33%. To further explain, the question is asking for the percentage change in the quantity of maize demanded. From the information given, we know that 12,000kg was demanded at N20 per kg and 8,000kg was demanded at N30 per kg. This means that the demand for maize decreased from 12,000kg to 8,000kg, which is a difference of 4,000kg. To find the percentage change, we divide this difference by the initial quantity demanded (12,000kg) and multiply by 100% to get the percentage change, which is 33.33%. This means that the quantity of maize demanded decreased by 33.33% due to the change in price.

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Igneous rocks can be identified by their texture and mineral composition. If the rock has a smooth, glass-like surface, it has a "glassy appearance." If the rock has a rough, uneven surface with large crystals, it has a "coarse texture." If the rock has visible layers, it has a "stratified" appearance. If the rock contains fossils, it is not an igneous rock, as fossils form in sedimentary rocks, not in rocks formed from molten magma.

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The fencing and partitioning of a pastureland into paddocks is meant to control grazing and ensure the regeneration of pasture. By dividing the pasture into smaller areas or paddocks, farmers can control the movement of livestock and prevent overgrazing. This allows the pasture to recover and regrow, ensuring a sustainable source of food for the animals. Additionally, paddock grazing can improve soil health and reduce soil erosion, as livestock are concentrated in smaller areas for shorter periods of time. Ultimately, paddock grazing can lead to a healthier and more productive pasture, benefiting both the farmer and the animals.

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Tapeworms, liver flukes, and roundworms are all types of parasites that can infect both animals and humans. These parasites can cause various health problems and even death in severe cases. Fortunately, there are several methods to control these parasites: 1. Flushing: Flushing involves cleaning out the digestive system of an animal to remove any parasites. This can be done by giving the animal a special diet or medication that will cause them to excrete the parasites from their system. 2. Drenching: Drenching involves giving an animal medication orally to kill any parasites in their system. This medication can come in the form of a pill or liquid. 3. Dipping: Dipping involves immersing an animal in a solution that kills any parasites on their skin. This method is typically used for external parasites, such as ticks or lice. 4. Fumigation: Fumigation involves using chemicals to kill parasites in an enclosed environment, such as a barn or stable. This method is not typically used for controlling parasites in animals. In summary, the most effective methods to control tapeworms, liver flukes, and roundworms in animals are flushing and drenching. Dipping is useful for external parasites, while fumigation is not typically used for controlling parasites in animals. It's important to consult a veterinarian to determine the best method for controlling parasites in your animals.

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The statement "the apiary should not be fenced to allow for proper ventilation" is not a correct precaution measure in beekeeping. While proper ventilation is important for the health of bees, fencing an apiary is an important precaution measure to protect both the bees and people who may be near the apiary. Fencing can help prevent people from accidentally disturbing the bees and protect them from potential predators. On the other hand, wearing protective clothing and placing warning signs near an apiary are indeed important precautions for beekeeping. And locating apiaries far from human dwellings can also help reduce the risk of bee-human interactions.

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The crop that is not a fiber crop is onion. Fiber crops are plants grown specifically for their fibers, which can be used to make textiles, ropes, paper, and other materials. Cotton, jute, and sisal are all examples of fiber crops. Cotton is one of the most commonly used fiber crops and is widely used to make clothing, towels, and sheets. Jute is a plant that produces strong and durable fibers, which are used to make burlap sacks and rope. Sisal is another plant that produces fibers that are commonly used for rope and twine. On the other hand, onion is a vegetable crop that is primarily grown for its edible bulbs. While onion leaves and stems can be used to make fibers, they are not typically grown or harvested for this purpose. Instead, onion fibers are usually considered a byproduct of onion production, and are not used on a large scale. Therefore, onion is not considered a fiber crop.

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Rhizobium is not directly involved in the nitrogen cycle. The nitrogen cycle is the process by which nitrogen is converted between different forms in the environment, such as from atmospheric nitrogen gas (N2) to ammonium (NH4+) and nitrate (NO3-) ions that plants can use for growth. This cycle involves a variety of microorganisms that play different roles in the process. Bacillus, Nitrobacter, and Nitrosomonas are all involved in the nitrogen cycle. Nitrosomonas converts ammonium to nitrite, and Nitrobacter converts nitrite to nitrate. Bacillus, on the other hand, plays a role in the decomposition of organic matter and the release of ammonium into the soil. Rhizobium is a soil bacteria that forms a symbiotic relationship with legume plants, helping them to convert atmospheric nitrogen into a form that the plant can use. While this process indirectly contributes to the nitrogen cycle, it is not directly involved in the conversion of nitrogen between different forms in the environment.

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The statement that is not true about farming in West Africa is "mechanisation is fully adopted." Farming in West Africa is predominantly manual, and farm labour is highly inefficient. This is because most farmers in the region lack access to modern farming technologies, such as tractors, harvesters, and irrigation systems. As a result, they rely on traditional farming methods, which are time-consuming and labor-intensive. Farm workers in West Africa are often poorly paid, and getting reliable labour is difficult. Many farmers in the region cannot afford to pay their workers a decent wage, and this, coupled with the lack of access to social protection programs, makes it difficult for farm workers to make ends meet. However, contrary to the options given, mechanisation is not fully adopted in West Africa. The high cost of modern farming equipment and limited access to credit facilities means that many farmers cannot afford to purchase modern farm equipment. This is compounded by the fact that the terrain in many parts of West Africa is not suitable for mechanised farming. In summary, while farm labour is highly inefficient, farm workers are poorly paid, and getting reliable labour is difficult, mechanisation is not fully adopted in West Africa.

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The agricultural system that combines crop production with forest establishment is called "taungya farming." In taungya farming, farmers grow crops like maize, beans, or vegetables alongside the establishment of a forest. The forest is established by planting trees in between the crops, which helps to improve soil quality, reduce erosion, and provide shade for the crops. Once the crops have been harvested, the trees continue to grow, providing timber and other forest products. This system is commonly used in tropical regions where there is a high demand for food and timber but limited land available for cultivation.

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A pack contains 10 crates of eggs, and each crate contains 30 eggs. To find the total number of eggs in 2 packs, we need to multiply the number of crates in 2 packs by the number of eggs in each crate. So, 2 packs contain 2 x 10 = 20 crates of eggs. Multiplying the number of crates (20) by the number of eggs per crate (30), we get: 20 x 30 = 600 Therefore, there are 600 eggs in 2 packs assuming a pack contains 10 crates of eggs.

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Threshing is the process of separating rice grains from the panicle. This is usually done by beating the panicles to loosen the grains. So, the statement "Rice grains are separated from the panicle" is true and corresponds to option (A) and (D). During the threshing process, there is a possibility of breakage of some grains. This is because the grains are subjected to a lot of force, and some of them may be damaged. Therefore, the statement "Breakage of some grains could occur" is also true and corresponds to option (A) and (D). However, the statement "The grains are polished" is not true. Polishing is a separate process that is done after threshing to remove the outer layer of the grain. This is done to give the rice a shiny appearance and improve its texture. Therefore, option (B) and (C) are not correct. In conclusion, the correct options are either (A) or (D), which are I and II Only, or I, II and III.

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The factor that is monitored with the use of wet and dry hygrometer in a brooder house is relative humidity. Relative humidity refers to the amount of moisture present in the air, expressed as a percentage of the maximum amount of moisture that the air could hold at a given temperature. In a brooder house, maintaining the correct relative humidity is essential for the health and well-being of the young birds being raised. A wet and dry hygrometer is a simple instrument used to measure relative humidity. It consists of two thermometers, one of which has a wet wick wrapped around its bulb. The wet wick is exposed to the air, and as the water evaporates, it cools the thermometer, causing the temperature to drop. The difference in temperature between the wet and dry thermometers is used to calculate the relative humidity. In a brooder house, the wet and dry hygrometer is used to ensure that the relative humidity is within the appropriate range for the age and type of birds being raised. Too high a humidity can lead to respiratory problems and the growth of harmful bacteria and fungi, while too low a humidity can cause dehydration and other health issues. By monitoring relative humidity with the wet and dry hygrometer, the caretakers of the brooder house can make adjustments to ventilation, heating, and other environmental factors as needed to maintain the optimal conditions for the birds' health and growth.

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The crop that can conveniently replace maize in the table is millet. Millet is a small, drought-resistant grain that grows well in hot, arid climates. It is a good source of nutrients such as protein, fiber, vitamins, and minerals. Millet can be cooked in a variety of ways, including boiling, steaming, roasting, or grinding into flour for use in baking. Millet is a great substitute for maize because it is a versatile crop that can be used in many of the same ways as maize. For example, millet can be used to make porridge, bread, cakes, and even beer, just like maize. Millet is also more tolerant to drought and can grow in areas where maize may struggle to thrive. Overall, millet is a nutritious and versatile crop that can be a suitable replacement for maize in many contexts.

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The statement that is not a reason for feeding farm animals is "production of inorganic manure." Feeding farm animals is necessary to provide them with the nutrients they need for energy, growth, and maintenance of body tissues. It is also important to protect them from diseases. However, the production of inorganic manure is a byproduct of the digestion process in animals, and it is not the primary reason for feeding them. Feeding farm animals has various benefits, including increasing their productivity, improving their health, and ensuring the quality of the products they produce, such as meat, milk, and eggs. Inorganic manure, on the other hand, is a secondary benefit that farmers can obtain from their animals, which can be used as fertilizer for crops. Therefore, while the production of inorganic manure is a positive outcome of feeding farm animals, it is not the main reason for doing so.

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A farmer whose production exceeds point C will experience a surplus to the market. In economics, point C represents the equilibrium point where the supply of a product matches the demand for that product. If a farmer's production exceeds this equilibrium point, it means that they are producing more than what is demanded in the market. This surplus will result in a decrease in the price of the product, as the farmer tries to sell the excess supply. This decrease in price could lead to a decrease in revenue generated for the farmer. However, if the farmer can find alternative markets or ways to store the excess supply, they can still make a profit from the surplus. In some cases, a surplus could also lead to a decrease in the cost of production, as the farmer tries to reduce their expenses to maintain profitability. Nonetheless, a surplus to the market is generally considered better than a shortfall in supply, as it means that there is an abundance of the product available for consumers.

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A cost-effective way of disseminating urgent information to a large number of farmers at the same time is through mass media. Mass media refers to various channels such as television, radio, newspapers, and social media that can reach a large audience at once. These channels can be used to broadcast urgent information, such as weather alerts, disease outbreaks, market prices, and new farming practices to farmers in different locations. By using mass media, farmers can receive information quickly and simultaneously, without the need for costly travel or physical demonstrations. This makes it an efficient way to disseminate information and promote adoption of new technologies, practices or policies that can improve farming productivity and livelihoods.

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A pest that attacks stored maize grain is a rodent. Rodents such as mice and rats are attracted to stored grains like maize because they provide a source of food and shelter. These pests can cause significant damage to stored maize grain by feeding on the kernels and contaminating the grain with their feces and urine, which can lead to mold growth and spoilage. Infestations can also result in significant economic losses for farmers and food storage facilities. Therefore, it is important to implement effective pest control measures to prevent and manage rodent infestations in stored maize grain.

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The factor of production that has the characteristics of being a free gift of nature, limited in supply, and immobile is land. "Free gift of nature" refers to the fact that land is a natural resource that is not created by humans. It includes all the gifts of nature such as water bodies, forests, mineral deposits, and soil. "Limited in supply" means that there is a finite amount of land available, and it cannot be produced or manufactured by humans. Therefore, the supply of land is fixed. "Immobile" means that land cannot be moved from one place to another. It is fixed in location, and its location is an essential factor in determining its value. Taken together, these characteristics make land a unique factor of production. Unlike other factors of production, such as labor or capital, land is not produced or manufactured by human effort. It is a fixed and finite resource that is essential for many economic activities, including agriculture, mining, and construction. Therefore, land is a critical resource for economic development, and its scarcity and immobility make it a valuable and limited resource. Thus, land is the factor of production that has the given characteristics.

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The water which rises above the water table in the soil and is held in fine medium pores between soil particles by surface tension is called "capillary water". Capillary water is able to rise above the water table because of the combined forces of adhesion (attraction between water and soil particles) and cohesion (attraction between water molecules). These forces enable water to move upwards through narrow pores against the force of gravity. In simpler terms, imagine a sponge dipped in water. The water rises up the sponge through capillary action because the tiny spaces between the sponge's fibers are able to hold the water due to surface tension. Similarly, in soil, the capillary action causes water to move upwards against gravity and be held in the spaces between soil particles. This capillary water is important for plant growth as it is the water that is available to plants for uptake through their roots.

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The correct option to correct nitrogen deficiency in maize plants is sulphate of ammonia. Nitrogen is an essential nutrient for plant growth and plays a key role in the formation of chlorophyll and the production of proteins. When a maize plant lacks nitrogen, its leaves may turn yellow and stunted growth may occur. Sulphate of ammonia is a fertilizer that contains nitrogen in the form of ammonium sulphate. When applied to the soil, the ammonium sulphate breaks down and releases nitrogen, which is taken up by the roots of the maize plant. This helps to correct the nitrogen deficiency and improve the overall health and growth of the plant.

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Of the given options, drip irrigation is the most efficient method of irrigation in terms of water conservation. Drip irrigation involves the slow and steady release of water directly onto the roots of the plants. This method reduces water waste, as the water goes exactly where it is needed and minimizes evaporation. Additionally, because the water is delivered directly to the roots, there is less runoff and less chance of water being lost to erosion. In comparison, flood irrigation involves flooding a field with water, which can lead to water loss through runoff and evaporation. Furrow irrigation and border irrigation are similar to flood irrigation in that they involve the flooding of fields, but they are less efficient than drip irrigation. Therefore, for efficient water conservation, drip irrigation is the best method out of the given options.

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To determine the percentage of humus in the soil sample, we need to first calculate the mass of the humus that was present in the original soil sample. Humus is the organic matter in soil that remains after the decomposition of plant and animal residues. The mass of the humus in the original soil sample can be calculated by subtracting the mass of the burnt soil from the mass of the oven-dried soil: Mass of humus = Mass of oven-dried soil - Mass of burnt soil Mass of humus = 8 g - 1.6 g Mass of humus = 6.4 g Therefore, the mass of humus in the soil sample is 6.4 g. To calculate the percentage of humus in the soil sample, we need to divide the mass of humus by the mass of the original soil sample and then multiply by 100: Percentage of humus = (Mass of humus / Mass of original soil sample) x 100% Percentage of humus = (6.4 g / 8 g) x 100% Percentage of humus = 80% Therefore, the percentage of humus in the soil sample is 80%. So, option D is the correct answer.

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The crops which grow and mature within a few weeks of their cultivation are called ephemeral crops. These crops have a very short life cycle and complete their growth and development quickly. They typically require less time and effort to cultivate and can provide a quick harvest. Examples of ephemeral crops include lettuce, radishes, and spinach, which can be harvested in as little as 4-6 weeks after planting. Ephemeral crops are typically grown in cooler months or in regions with mild climates, as they can be sensitive to extreme heat and moisture. In contrast, annual crops complete their life cycle within a year, biennial crops take two years to mature, and perennial crops can continue to grow and produce for several years.

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(a) Cultivation of Citrus spp

(i) Method of propagation: Citrus is propagated both sexually (by seeds) and, more commonly for commercial orchards, vegetatively by budding (T or shield budding) onto a resistant rootstock such as rough lemon or sour orange. Budding is preferred because it keeps the desirable qualities of the parent, ensures early fruiting and gives uniform trees.

(ii) Spacing in the field: Citrus is planted at about 6 m x 6 m to 8 m x 8 m (approximately 150 to 280 trees per hectare), depending on the species and soil fertility. Wide spacing allows light penetration, air circulation and easy movement for spraying and harvesting.

(iii) Nursery practices:

• Prepare fine, well drained nursery beds and sow rootstock seeds.
• Provide partial shade and water regularly.
• Weed, and apply fertilizer to raise vigorous seedlings.
• Bud the seedlings when the stems reach pencil thickness.
• Harden off seedlings before transplanting to the field.

(iv) Pests: Aphids, citrus leaf miner, fruit flies, mealy bugs, scale insects and citrus psyllid.

(v) Diseases: Citrus canker, gummosis (foot rot caused by Phytophthora), citrus greening (HLB), tristeza virus and sooty mould.

(b) Definitions

(i) Surface irrigation: The application of water to farmland by allowing it to flow over the soil surface by gravity, for example through furrows, basins or borders, so that it infiltrates into the root zone.

(ii) Surface drainage: The removal of excess water from the top of the land surface by means of open channels, ditches or graded slopes so that waterlogging is prevented.

(c) Advantages

(i) Surface irrigation:

• It is cheap and simple, requiring little equipment or technical skill.
• It does not require pumping energy where gravity flow is available.
• It can cover large areas and helps leach out harmful salts from the soil.

(ii) Surface drainage:

• It removes excess water and prevents waterlogging, improving soil aeration.
• It reduces soil erosion and the incidence of water-borne diseases.
• It allows earlier cultivation and prevents root rot, improving crop yield.

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(a) Completed disease table:

(b) Five advantages of the battery cage system in poultry production:

1. Efficient use of space through high stocking density.
2. Eggs are clean and easily collected with little breakage.
3. Diseases and parasites are easily controlled since birds do not touch their droppings.
4. Individual birds are easily observed and poor layers are readily culled.
5. Feed wastage, broodiness and cannibalism are greatly reduced.

(c) Five reasons why some extension programmes are not successful in West Africa:

1. Inadequate funding of extension services.
2. Too few and poorly trained extension agents (a low agent-to-farmer ratio).
3. Poor roads, transport and communication infrastructure.
4. Illiteracy of farmers and their resistance to change.
5. Inconsistent government policies and weak research-extension linkage.

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(a)(i) Area of the rectangular farmland

Area of a rectangle = length x breadth. The two measurements must first be in the same unit. Converting the length to kilometres, length = 0.2 km and breadth = 2,200 km.

\[ \text{Area} = 0.2\,\text{km} \times 2{,}200\,\text{km} = 440\,\text{km}^2 \]

(If the breadth is taken as 2,200 m, then converting length 0.2 km = 200 m gives Area = \(200\,\text{m} \times 2{,}200\,\text{m} = 440{,}000\,\text{m}^2 = 44\ \text{hectares}\). The key principle is to keep both dimensions in the same unit before multiplying.)

(a)(ii) Two importance of a balance sheet to a farm manager

• It shows the financial position (assets, liabilities and net worth) of the farm business at a particular date.
• It helps the manager to obtain credit or loans, since lenders assess the farm's solvency from it, and it guides sound financial planning and decision making.

(b) Five sources of agricultural loans in West Africa

• Commercial banks.
• Agricultural development banks (for example the Bank of Agriculture in Nigeria).
• Cooperative societies and thrift/credit unions.
• Government agencies and special credit schemes.
• Money lenders, friends and relatives.

(c) Three reasons wood shavings are preferred to sawdust on a deep litter floor

• Wood shavings absorb moisture well yet remain loose and do not cake, keeping the litter dry.
• Sawdust is fine and dusty and can be eaten by the birds or inhaled, causing respiratory problems and impaction; shavings avoid this.
• Wood shavings allow better aeration and are easier to turn and manage, reducing dampness, ammonia and disease.

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(a) Life cycle of the variegated grasshopper (Zonocerus variegatus)

The variegated grasshopper undergoes incomplete metamorphosis with three stages:

1. Egg stage: The female lays batches of eggs in egg pods buried in moist soil. The eggs remain in the soil and hatch after the dry season, usually with the onset of rains.
2. Nymph stage: The hatched young ones (nymphs) resemble the adults but are smaller and wingless. They feed on vegetation and pass through several moults (instars), gradually developing wing buds.
3. Adult stage: After the final moult the nymph becomes a fully winged adult with the characteristic variegated (multi-coloured) body. Adults mate, and the females lay eggs, so the cycle continues.

(b) Five ways diseases are spread on crop farms

• By insect vectors (for example aphids and whiteflies transmitting viruses).
• Through infected planting materials such as seeds, cuttings and tubers.
• By wind carrying fungal spores.
• By irrigation and rain water carrying pathogens from plant to plant.
• Through contaminated farm tools, implements and the hands of farm workers.

(Also by soil harbouring pathogens, and by man and animals moving through the field.)

(c) Six characteristics of a good layer

• It has a bright red, well developed comb and wattles.
• It has a soft, large and moist vent.
• It has a wide space (three to four fingers) between the pelvic bones.
• It is alert, active and has bright eyes.
• It has a soft, pliable and expanded abdomen.
• It has bleached (pale) shanks and beak, showing that pigment has gone into egg production, and it lays many large eggs.

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(a)

(i) Soil texture refers to the proportion of sand, silt, and clay particles in the soil. The texture affects the soil's water-holding capacity, aeration, and nutrient retention capacity.

(ii) Soil profile refers to the vertical section of soil, showing different layers or horizons, with varying physical and chemical properties. These layers are formed over time due to weathering and biological processes and are important for understanding the soil's characteristics and potential for crop production.

(b)

(i) Three advantages of grafting are:

• Increased resistance to pests and diseases
• Improved plant vigor and yield
• Ability to grow different varieties on the same rootstock for efficient use of space and resources.

(ii) Two crops that could be propagated by grafting are fruit trees (such as apples, peaches, and plums) and grapevines.

(c) Four cultural practices that could be used to replenish nutrients in the soil are:

• Crop rotation: growing different crops in sequence to reduce soil depletion of specific nutrients
• Cover cropping: planting non-cash crops to add organic matter to the soil and fix nitrogen
• Green manuring: intentionally growing and then plowing under specific crops to improve soil fertility
• Addition of organic matter: applying compost, manure, or other organic materials to the soil to improve its nutrient content and structure.

(d) Four measures that could be adopted by farmers to control pests in grain stores are:

• Proper storage: using clean and dry containers with tight-fitting lids to prevent entry of pests
• Regular cleaning: sweeping, vacuuming, and removing debris to eliminate hiding places for pests
• Fumigation: using chemicals to kill pests in stored grains
• Monitoring: regularly checking for signs of pest infestation and taking immediate action to prevent further spread.

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(a) Two solutions to each problem of agricultural development in Africa:

(i) Poor transportation:

• Construct and maintain good rural/feeder roads linking farms to markets.
• Provide adequate means of transport such as vehicles, and develop railways and waterways.

(ii) Environmental degradation:

• Practise soil-conservation measures such as afforestation, cover cropping, terracing and controlled grazing.
• Avoid bush burning and enforce laws against deforestation and pollution.

(iii) Use of crude farm tools:

• Introduce and subsidise modern machines and improved implements for farmers.
• Train farmers in the use and maintenance of modern equipment and provide credit to buy them.

(b) Three precautions when using each type of farm power:

(i) Animal power:

• Do not overload or overwork the animals; give them rest.
• Feed and water them well and keep them healthy.
• Use well-fitting harnesses to avoid injuring the animals.

(ii) Electrical power:

• Avoid touching electrical wires/switches with wet hands.
• Repair faulty wiring and insulate/earth all connections properly.
• Switch off the mains before servicing equipment and avoid overloading circuits.

(c) Six reasons for maintaining farm tools and implements:

• To make them last longer (increase durability).
• To keep them in good working condition and efficient.
• To prevent rust and damage.
• To reduce the cost of frequent repair and replacement.
• To prevent accidents/injury during use.
• To ensure good quality of work and save time and labour.