WAEC SSCE - Agricultural Science - 1990

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The function of Nitrosomonas in the nitrogen cycle is nitrification. Nitrosomonas is a type of bacteria that plays an important role in converting ammonia into nitrite during the nitrogen cycle. This process is known as nitrification, and it involves the conversion of nitrogen from one form to another that can be used by plants. Nitrosomonas converts ammonia, which is a waste product of animal and plant metabolism, into nitrite. Nitrite is then further converted into nitrate by another type of bacteria called Nitrobacter. Nitrate is a form of nitrogen that can be taken up by plants and used to make proteins and other important compounds. Therefore, the function of Nitrosomonas in the nitrogen cycle is important for the growth and development of plants.

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The disbanded produce marketing boards in Nigeria were responsible for the marketing and distribution of agricultural commodities. These boards were created to ensure that farmers received fair prices for their crops and to facilitate the marketing of these crops to consumers. Of the options given, yam is the commodity that the disbanded produce marketing boards in Nigeria did not deal with. Yam is an important crop in Nigeria, but it is not typically sold through marketing boards. Other crops like oil palm, rubber, cocoa, and groundnut are typically marketed through produce marketing boards to ensure fair prices and efficient distribution.

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Investments with long life span in agricultural economics are otherwise known as "capital." Capital refers to any asset that can be used in the production of goods or services, including machinery, buildings, land, and other resources. In agricultural economics, capital investments may include purchasing land, buildings, and equipment used in farming operations that have a long life span and can generate income for many years. These investments are often critical to the success of agricultural enterprises and require careful planning and management.

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Crop rotation is the farm practice that does not have a very harmful effect on the soil. Crop rotation involves planting different crops on the same piece of land in a planned sequence over time. This farming method helps to maintain soil fertility, increase soil organic matter, and prevent soil erosion. By rotating crops, the soil is not depleted of specific nutrients since different crops have varying nutrient requirements. This practice also reduces the risk of pest and disease infestations since the pests and diseases specific to one crop cannot thrive on a different crop. Therefore, crop rotation is an effective and sustainable way of maintaining soil health and productivity.

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The leguminous forage crop that is not actually leguminous is "panicum maximum". Panicum maximum is a type of grass commonly used for forage, but it is not part of the legume family. Leguminous forage crops, on the other hand, are plants that belong to the family Leguminosae and have the ability to fix nitrogen in the soil. This means that they are able to take nitrogen gas from the air and convert it into a form that can be used by plants, which can reduce the need for nitrogen fertilizers. Examples of leguminous forage crops include Centrosema pubescens, Vigna sinensis, Stylodsnyhrd htsvilid, and Pueraria phaseoloides.

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Farm records and accounting help the farmer to manage his farm as a business. By keeping track of income and expenses, the farmer can make informed decisions about what crops to grow, when to sell them, and how to allocate resources. This allows the farmer to optimize his profits and minimize losses. Additionally, keeping farm records can help the farmer to identify areas where improvements can be made, such as in crop yields or equipment maintenance. By monitoring his financial performance over time, the farmer can also identify trends and make adjustments to his farming practices accordingly. Overall, maintaining accurate farm records and accounting is crucial for any farmer who wants to run his farm as a successful and profitable business.

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The most common weed of pastures in Nigeria is spear grass. This weed is a type of grass that is often found growing in grazing areas and can be difficult to control. It can compete with desirable forage species and reduce the quality and quantity of available forage for livestock. In addition, spear grass can be dangerous for livestock to consume as it can cause injury to the mouth and digestive tract. Effective weed control measures, such as mowing, grazing management, and herbicide application, can help to manage spear grass and other weeds in pastures.

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The type of soil formed is influenced by several factors, including climate, vegetation, topography, parent material, and time. These factors interact with each other in complex ways, leading to the formation of different types of soils. However, one of the factors that do not affect the type of soil formed is farming systems. Farming systems are human activities that are carried out on the soil after it has been formed. They can modify the properties of the soil, but they do not have a direct influence on the type of soil that is formed. The other factors, such as climate, vegetation, topography, and parent material, all play a crucial role in determining the characteristics of the soil that is formed in a particular location.

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The factor affecting land availability and use that is a socio-economic factor is "population pressure." Population pressure refers to the demand for land resulting from the increasing number of people in an area. As population grows, people require more land for living, agriculture, industry, and other activities. The pressure on land can lead to the conversion of forests, wetlands, and other natural habitats into farms, urban areas, and other developments. This can have a significant impact on the environment, biodiversity, and the sustainability of natural resources. Therefore, population pressure is a socio-economic factor as it is driven by social and economic forces, such as urbanization, migration, and economic growth.

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Soil can be drained by various methods, but one of the options listed above does not aid in the process of drainage. Sprinklers are used for irrigation and are not effective in draining soil. Channels, gutters, ditches, and porous pipes are all examples of drainage systems that help move excess water away from the soil, preventing waterlogging and erosion. Therefore, the correct answer is "sprinklers."

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Glaciation will not contribute to soil formation in Nigeria. Glaciation is the process of forming and moving glaciers, which are large masses of ice that can erode and transport soil and rock materials. This process is not present in Nigeria because the country is located in a tropical region with a hot and humid climate. Nigeria has never experienced glaciation because the temperature in the region is high enough to prevent the formation and movement of glaciers. Soil formation in Nigeria is primarily influenced by other factors such as temperature, rainfall, parent material, and vegetation. These factors contribute to the weathering of rocks and the breakdown of organic matter, which over time, leads to the formation of soil.

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Phosphorus is a macro-nutrient. Macro-nutrients are essential elements required by plants in large quantities for healthy growth and development. These nutrients include nitrogen, phosphorus, and potassium (NPK). Phosphorus plays a crucial role in plant growth, energy transfer, and photosynthesis. It is essential for root development, flowering, and seed formation. Phosphorus is also involved in the synthesis of DNA, which is the genetic material in cells. Since phosphorus is required in large amounts by plants, it is considered a macro-nutrient.

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Newcastle disease of poultry affects the nervous system and respiratory tract of birds. This viral disease can cause respiratory symptoms like coughing, sneezing, and nasal discharge, as well as neurological symptoms like tremors, paralysis, and twisting of the neck. It can also lead to decreased egg production and quality. The disease can spread rapidly and can be fatal in some cases, so it is important to practice good biosecurity measures to prevent its spread.

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Root knot of tomato is caused by a nematode. Nematodes are microscopic, worm-like organisms that can live in soil and feed on plant roots. Root knot nematodes are a type of nematode that can cause significant damage to tomato plants. They infect the roots of the plant and cause the formation of characteristic galls or knots on the roots. These galls can interfere with the plant's ability to take up water and nutrients, leading to stunted growth, reduced yields, and in severe cases, plant death. Controlling root knot nematodes can be challenging, but measures such as crop rotation, soil solarization, and the use of resistant tomato varieties can help manage the problem.

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Maize grows best on loamy soil. This is because loamy soil has a good balance of sand, silt, and clay particles, which allows for good drainage, moisture retention, and nutrient availability. Maize also prefers a slightly acidic soil pH between 6.0 and 6.8, which is common in loamy soils. Sandy soils drain too quickly and don't hold enough moisture, while clayey soils retain too much water and can become waterlogged. Silty-clay soils are heavy and compact, which can make it difficult for maize roots to penetrate and grow. Therefore, loamy soil is the most suitable soil type for maize growth and development.

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Taungya farming is a farming system that involves the combination of crop husbandry and forestry. It is a traditional agroforestry system that originated in Southeast Asia, but it is also practiced in other parts of the world, including Africa. In Taungya farming, farmers cultivate crops such as maize, cassava, or beans between newly planted trees. The farmers plant the trees in rows and cultivate crops in between them during the first few years while the trees are still young and do not have a canopy. The crops provide an additional source of income for the farmers, while the trees provide environmental benefits such as soil conservation, carbon sequestration, and biodiversity conservation. After a few years, the trees grow to maturity, and the farmers can harvest them for timber or non-timber forest products. In summary, Taungya farming involves the combination of crop husbandry and forestry, where farmers cultivate crops in between newly planted trees. This system provides environmental and economic benefits for the farmers and the environment.

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The disadvantage of using organic manure on the soil is the spreading of pests and diseases. Organic manure may contain pests and diseases that can be harmful to plants and crops, and when spread on the soil, it can introduce these pests and diseases into the soil, which can then affect the growth and health of plants. Therefore, it is important to ensure that the organic manure used is properly composted and free of pests and diseases before it is applied to the soil.

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An incubator is a device used to supply heat to fertilized eggs to enable the development of the chicks inside. The eggs are placed in the incubator, which maintains a constant temperature and humidity level. The heat from the incubator is necessary for the chicks' growth and development until they hatch. Incubators are not used to supply heat to day-old chicks, sick fowls, cockerels, or poultry attendants.

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The type of feed that contains all the necessary nutrients required by an animal in the right concentrations and proportions is called a balanced diet. A balanced diet provides the right amount of energy, protein, vitamins, minerals, and other essential nutrients required for the growth and development of an animal. A balanced diet helps to maintain good health and improve the productivity of the animal. It is important to provide a balanced diet to animals to ensure that they remain healthy and productive throughout their life.

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Soil may be exposed to erosion when a pasture is 'overgrazed'. Overgrazing occurs when too many animals graze on a pasture, causing the vegetation to be consumed faster than it can grow back. This results in bare patches of soil being exposed, which can be easily eroded by wind and rain. The roots of the vegetation normally help to hold the soil in place, and when the vegetation is removed through overgrazing, the soil becomes vulnerable to erosion. Erosion can lead to the loss of topsoil, which is the most nutrient-rich layer of the soil and is essential for plant growth. It can also result in the degradation of the soil structure, which can affect water infiltration and retention and ultimately reduce the productivity of the pasture. Therefore, proper grazing management is essential to prevent overgrazing and soil erosion, and maintain a healthy and productive pasture.

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The concept of consumer sovereignty in agriculture implies that the consumer, not the farmer, determines what to produce. This means that farmers will produce what consumers demand or what they are willing to buy. In other words, the farmer will consider what the consumer wants before deciding what crops to plant or what animals to raise. This concept is important because it ensures that farmers are producing goods that are in demand and that consumers will actually purchase. It also helps to create a more efficient and responsive agricultural system that is able to adapt to changing consumer preferences and market conditions.

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The role of government in agricultural production does not include the provision of labor. The government plays an important role in supporting agricultural production through policies and programs that provide farmers with access to credit and loans, building storage facilities for crops, establishing efficient marketing outlets for agricultural products, and providing subsidies to support the production of certain crops. However, the government does not typically provide labor for agricultural production. This responsibility falls on the farmers themselves or on hired workers. The government may have labor regulations that affect agricultural production, but it is not responsible for providing the actual labor needed to grow crops or raise livestock.

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A fish pond in an enclosed body of water is primarily used for rearing fish for consumption. A fish pond is an artificial body of water created to provide a controlled environment for raising fish. The pond is usually enclosed, and the water is managed to maintain optimal conditions for the growth and survival of fish. The primary purpose of a fish pond is to raise fish for food production. In a fish pond, fish are fed with a balanced diet, and their growth is monitored to ensure they reach a desirable size for consumption. While fish ponds can also be used to rear aquatic organisms for feeding fish, keeping ornamental fish and aquatic plants, storing fish, and other organisms, their primary use is for the production of fish for human consumption.

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When farmers receive agricultural credits in the form of cash, they typically use the money to pay for expenses related to their farming business. This could include purchasing seeds, fertilizer, equipment, and other inputs necessary for farming. By using the credit to cover these costs, farmers can make sure that the total cash value of their crops is greater than their expenses, allowing them to turn a profit. The credit is not typically used for disseminating the latest farming techniques, implementing new policies, or investigating the cause of low agricultural production.

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The reason why planting a mixture of grass and legume on a pasture is not economical to the farmer is that the mixture can harbor pests. A mixture of grass and legume is a common practice in pasture management because it provides a balanced feed for livestock and reduces the cost of purchasing additional feed. Additionally, the mixture helps prevent soil erosion and saves on fertilizer costs. However, a disadvantage of planting a mixture is that it can harbor pests, such as insects and diseases, which can negatively impact crop yields and the health of livestock.

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Dissolved oxygen in fish ponds is maintained at a normal level in order to keep fish activities normal. Fish need oxygen to survive, and they obtain it from the water through their gills. The amount of dissolved oxygen in the water can vary depending on factors such as temperature, water movement, and the presence of aquatic plants and algae. If the dissolved oxygen level in a fish pond drops too low, the fish may become stressed and their growth and health may be affected. In extreme cases, low dissolved oxygen levels can lead to fish kills. Therefore, it is important to maintain a normal level of dissolved oxygen in the fish pond to keep the fish healthy and active. There are several ways to maintain dissolved oxygen levels in a fish pond, such as aerating the water with a pump or fountain, adding oxygen-producing plants, or reducing the amount of organic matter in the water. By maintaining the proper level of dissolved oxygen, fish farmers can improve the quality of their fish and ensure a healthy and productive fish farming operation.

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The mosaic symptom commonly associated with viral diseases of crops can be best observed on the leaves. Mosaic symptoms refer to a pattern of light and dark green or yellow patches that can appear on the leaves of infected plants. This pattern resembles a mosaic or patchwork, hence the name. This symptom is a common indicator of viral diseases that can affect a wide range of crops, including tomatoes, potatoes, cucumbers, and tobacco. Since the mosaic pattern is most visible on the leaves, it is the best place to observe and identify the symptom. However, symptoms may also appear on other parts of the plant, such as the stem or fruit, depending on the specific virus and the crop it infects.

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A castrated male fowl is known as a 'capon'. A capon is a rooster that has been surgically castrated before reaching sexual maturity. This is usually done to improve the quality of its meat, as capons tend to have more tender, flavorful, and juicy meat compared to regular roosters. Capons are also larger in size than regular roosters, and their meat has a more delicate flavor and texture. Capons were traditionally raised for meat in many parts of the world, and they are still considered a delicacy in some countries, particularly during festive occasions.

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The group that comprises only oil crops is "coconut, cotton, and sunflower". Coconut and sunflower are well-known oil crops used for cooking and manufacturing purposes. Cottonseed also contains oil that is used in cooking and making soap. Therefore, all three plants have commercially valuable oil that is extracted from their seeds or nuts.

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Palm oil is not a source of minerals in animal nutrition. Palm oil is a type of vegetable oil that is extracted from the fruit of oil palm trees. While it is a source of fat and energy, it does not provide significant amounts of essential minerals such as calcium, phosphorus, and iron, which are important for animal health and growth. On the other hand, green pastures, fish meal, blood meal, and cereal can all be sources of minerals in animal nutrition. Green pastures can provide minerals such as calcium and magnesium, while fish meal and blood meal are rich sources of protein as well as minerals like iron and zinc. Cereals, such as corn and wheat, can also provide essential minerals such as phosphorus and potassium.

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The destructive effects of variegated grasshoppers are most conspicuously observed on maize and cassava crops. These grasshoppers are voracious feeders and can consume large amounts of plant material, causing significant damage to crops. In the case of maize and cassava, these crops are particularly susceptible to damage from variegated grasshoppers because they are staple crops that are grown in large quantities and are a major source of food for many people. The damage caused by variegated grasshoppers can lead to significant losses for farmers and can have a serious impact on food security in affected areas.

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Give and take lines are often used in farm surveying to measure farms with irregular boundaries. Give and take lines are a surveying technique that involves starting from a fixed point and then taking measurements along the irregular boundary of a field or farm, while making adjustments to ensure that the final measurements are accurate and complete. The surveyor starts by measuring a line from a fixed point, and then adjusts the measurements to take into account any obstructions, such as trees or buildings, or any deviations from the expected shape of the boundary. This involves giving or taking measurements to ensure that the final boundary lines up correctly with the starting point. Give and take lines are commonly used in rural areas where farms may have irregular boundaries due to natural features or historical reasons. They are an important tool for accurately measuring and mapping farms, which is essential for land management, planning, and property valuation.

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Subsistence farming can be appropriately described as planting of crops and rearing of livestock for the benefit of the farmer and his family. The main purpose of subsistence farming is to produce enough food and other agricultural products to meet the basic needs of the farmer and their family. Unlike commercial farming, subsistence farming is not primarily focused on earning profits or exporting products for foreign exchange. Instead, subsistence farmers aim to sustain their livelihoods by growing crops and raising livestock for their own consumption and for the local community.

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The option that is not a limitation of farm mechanization is "labour." Farm mechanization can help farmers to reduce the amount of manual labor required for certain tasks, such as plowing, harvesting, and planting. By using machines, farmers can save time, increase efficiency, and improve productivity. However, the other options listed are all common limitations of farm mechanization. Technical know-how refers to the specialized knowledge and skills needed to operate and maintain farm machinery. Capital is required to purchase and maintain the machinery. Small holdings may make it difficult for farmers to afford the equipment or find space to store and use it. Lack of spare parts can make it difficult to repair or replace broken machinery, leading to downtime and reduced productivity.

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Forestry crops are trees that are grown and managed for the purpose of timber production, while other crops like vegetables and fruits are grown for consumption or processing. The crop that is not a forestry crop among the options listed is anarcadium. Anarcadium is the scientific name for cashew, which is typically grown for its edible nuts and not for timber production. In contrast, the other options listed are all tree species that are commonly grown and managed for timber production in forestry operations.

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The Nigerian government has helped farmers in marketing a particular crop through the establishment of marketing boards. These boards are responsible for purchasing the crops from farmers at fair prices and then selling them to wholesalers or exporters. By doing this, the government ensures that farmers have a market for their crops and are incentivized to produce more. The other options mentioned are not directly related to marketing crops, although they may indirectly support agricultural production in other ways.

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Extension agents play an important role in the life of rural farmers by providing them with valuable information and support. Here are eight functions of an extension agent:

1. Technology transfer: Extension agents introduce farmers to new farming technologies, including new crop varieties, improved crop management practices, and new equipment that can help them increase their yields and productivity.
2. Training and education: Extension agents conduct training sessions and provide education to farmers on best practices in farming, such as pest management, crop rotation, and soil conservation.
3. Market information: Extension agents provide information to farmers on market trends and prices, helping them make informed decisions on when to sell their crops and how to maximize their profits.
4. Financial management: Extension agents help farmers to develop sound financial management practices, including budgeting and record-keeping, to ensure that their farming operations remain profitable.
5. Networking and collaboration: Extension agents facilitate collaboration among farmers and between farmers and other stakeholders, such as input suppliers, buyers, and processors.
6. Disaster management: Extension agents help farmers to prepare for and respond to disasters, such as floods, droughts, and pest infestations, by providing them with information on how to mitigate risks and minimize losses.
7. Environmental conservation: Extension agents encourage farmers to adopt sustainable farming practices that help to protect the environment and preserve natural resources.
8. Community development: Extension agents work with farmers to identify and address social and economic issues in their communities, such as food security, health, and education.

In summary, extension agents are essential to the success and sustainability of rural farmers. They provide information, training, and support to farmers, helping them to adopt best practices and increase their yields, profits, and overall quality of life.

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Explanation:

Cocoa, yam, and millet are all important crops in Nigeria, with different climatic and soil requirements, cultural practices, and methods of propagation.

Cocoa requires a warm and humid climate with a well-distributed rainfall of 1500-2000mm per year and an annual temperature range of 21°C to 32°C. The crop is best grown in well-drained, deep, sandy loam or clay-loam soil with a pH of 5.5-7.0. Shade is required, as well as regular pruning and weeding. Propagation is by seeds or vegetative means, such as cuttings, budding or grafting.

Yam requires a warm and humid climate with an evenly distributed rainfall of 1200-1500mm per year and a temperature range of 25°C to 30°C. The crop grows best in deep, well-drained, loamy soil with good water holding capacity, pH range of 5.0-6.5, and rich in organic matter. Cultural practices include land clearing, mound construction, planting of stakes, planting of yam setts, and regular weeding and

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a) i) Farm surveying is the process of measuring and mapping out the physical features of a farm or agricultural land. This involves the use of surveying equipment to take accurate measurements of the land's boundaries, topography, and other features.

ii) The importance of farm surveying includes:

• Proper planning: Farm surveying enables farmers to accurately plan and design their farms for optimal land use and crop production.
• Land valuation: Farm surveying helps in determining the true value of agricultural land for sale or purchase.
• Legal documentation: Accurate survey measurements are required for legal documents such as deeds and titles.
• Conservation: Surveying helps farmers to identify areas that need conservation measures such as erosion control, water management, and soil conservation.
• Precision agriculture: With the help of survey data, farmers can adopt precision agriculture techniques to increase productivity, reduce waste, and maximize profits.

b) Four survey equipment commonly used in the farm are:

• Total Station: This is a modern electronic surveying instrument that uses a combination of lasers, infrared signals, and GPS technology to measure distances, angles, and elevations accurately.
• Global Positioning System (GPS): This is a satellite-based navigation system that provides accurate and reliable location data for farm mapping and crop management.
• Theodolite: This is an optical instrument used for measuring angles between two points on the ground. It is commonly used in boundary surveys and topographic mapping.
• Measuring tapes and chains: These are traditional surveying tools that are still commonly used today for measuring distances and laying out boundaries. They are simple and easy to use, making them ideal for smaller farms and simple survey tasks.

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(a) Rangeland is a type of land where natural vegetation such as grasses, shrubs, and other herbaceous plants grow and serve as a habitat for grazing animals. It is an extensive area of land used for livestock production and wildlife habitat.

(b) The seven practices of management and improvement of rangeland are as follows:

1. Grazing management: This practice involves regulating the number of animals grazing on the rangeland and the length of time they spend on the land to prevent overgrazing, which can lead to soil erosion and loss of vegetation.
2. Water management: Adequate water is necessary for the survival of plants and animals on the rangeland. Thus, the provision of water sources for livestock and wildlife is crucial to ensure the sustainability of the rangeland.
3. Weed control: The presence of invasive plant species can reduce the productivity and biodiversity of rangeland. Weed control practices such as mowing, herbicide application, and grazing management can help reduce the spread of invasive species.
4. Fire management: Fire can play a vital role in the management of rangeland by removing excess vegetation, promoting new growth, and reducing the risk of wildfire. Thus, controlled burning is used as a management tool to improve rangeland health.
5. Soil conservation: Soil erosion can be a significant problem on rangelands, leading to the loss of nutrients and decreased productivity. Conservation practices such as contour plowing, terracing, and conservation tillage are used to reduce soil erosion.
6. Wildlife management: Rangelands are home to a diverse range of wildlife, and managing their populations is essential to maintain ecological balance. Habitat improvement practices such as the provision of nesting sites and food sources are used to support the growth of wildlife populations.
7. Monitoring and assessment: Regular monitoring and assessment of the rangeland are essential to evaluate the effectiveness of management practices and identify potential issues that need to be addressed. This practice involves tracking plant and animal populations, soil health, and other indicators of rangeland health.

Overall, the management and improvement of rangeland require a holistic approach that balances the needs of livestock, wildlife, and the environment to ensure the long-term sustainability of the land.

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(a) Deweeding: Deweeding is the process of removing unwanted aquatic plants from the fish pond. Weeds compete with fish for oxygen, nutrients, and space, and can also harbor predators and disease. By removing weeds, fish can thrive in a healthier and more spacious environment, leading to a higher yield.

(b) Desilting: Desilting involves removing excess sediment or silt from the bottom of the fish pond. Over time, silt accumulates and reduces the depth of the pond, which can lead to overcrowding and poor water quality. By removing the excess silt, the pond can increase its capacity and maintain better water quality, providing a healthier environment for fish to grow and thrive.

(c) Supplementary feeding: Supplementary feeding involves providing additional food to the fish beyond what they can find in their natural environment. Fish that are well-fed grow faster and produce more offspring, leading to a higher yield. It's important to ensure that the supplemental feed is of high quality and appropriate for the type of fish being raised.

(d) Fertilization: Fertilization involves adding nutrients to the water to promote the growth of phytoplankton, which is the base of the food chain in the pond. Phytoplankton serves as food for zooplankton, which in turn is food for fish. By fertilizing the water, you can increase the amount of food available for fish, leading to faster growth and higher yields. It's important to use the right type and amount of fertilizer to prevent overgrowth of algae and other undesirable plant species.

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a) Soil structure refers to the arrangement of soil particles into groups or aggregates. These aggregates can range in size from small crumbs to larger clumps, and they can have different shapes and arrangements depending on the type of soil and the conditions in which it formed. Soil structure is important in agriculture because it affects the movement of air, water, and nutrients through the soil, which can impact plant growth and productivity. Good soil structure can allow for better root development, better water infiltration, and better nutrient availability.

b) Clay soil and sandy soil are two common soil types with different properties. Four properties of each are:

Clay soil:

1. High water-holding capacity
2. Low permeability to water and air
3. High nutrient-holding capacity
4. Sticky texture when wet

Sandy soil:

1. Low water-holding capacity
2. High permeability to water and air
3. Low nutrient-holding capacity
4. Loose texture

These properties are important to consider when choosing crops to plant and managing soil fertility. For example, crops that require a lot of water may not grow well in sandy soil because it cannot hold onto water, while crops that require good drainage may not grow well in clay soil because it can become waterlogged. By understanding the properties of different soil types, farmers can make informed decisions about how to manage their soil for optimal crop growth and productivity.

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a) Two major elements of climate are temperature and precipitation.

b) Climate and vegetation influence soil formation in the following ways:

1. Temperature: High temperatures can lead to faster decomposition of organic matter, while low temperatures can slow down this process. This can affect the amount of nutrients available in the soil. In addition, temperature can influence the rate at which chemical reactions occur in the soil, which can impact soil structure and composition.

2. Precipitation: Precipitation can influence the amount of water available in the soil, which can impact soil structure and composition. In addition, the pH of the soil can be influenced by the type and amount of precipitation that occurs in a particular region.

3. Vegetation cover: The type and density of vegetation cover can affect soil formation by influencing the amount of organic matter that is added to the soil, as well as the amount of water that is held in the soil. For example, forests typically have more organic matter and retain more water than grasslands.

4. Root exudates: Plants release organic compounds into the soil through their roots, which can influence soil structure and nutrient availability. Different types of plants release different types and amounts of exudates, which can impact the soil in unique ways.

5. Litter accumulation: Dead plant material can accumulate on the soil surface and become incorporated into the soil over time. This can contribute to the organic matter content of the soil and influence soil structure and composition.

6. Erosion: Climate and vegetation can also influence the rate of erosion in a particular area. Heavy rainfall and sparse vegetation cover can increase the risk of erosion, which can strip away topsoil and reduce soil fertility.

By understanding these relationships between climate, vegetation, and soil formation, farmers and land managers can make informed decisions about how to manage their soil for optimal crop growth and productivity.

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(a) Agricultural finance refers to the financial activities and services that are provided to support agricultural production and related activities. Agricultural credit, on the other hand, is a type of financing that is specifically designed to meet the needs of farmers and other participants in the agricultural sector. It provides the necessary funds to purchase agricultural inputs, equipment, and other necessities to grow and sell crops or raise livestock.

(b) There are several sources of agricultural credit available to small-scale farmers, including:

1. Banks and other financial institutions
2. Government programs and subsidies
3. Microfinance institutions
4. Cooperatives
5. Agricultural input suppliers that offer credit
6. Community-based organizations and NGOs

(c) There are several problems that can be associated with agricultural credit, including:

1. High interest rates: Agricultural credit can be associated with high interest rates, making it difficult for farmers to repay the loans.
2. Limited availability: In some areas, there may be limited access to agricultural credit, making it difficult for farmers to obtain the financing they need.
3. Lack of collateral: Many small-scale farmers may not have the necessary collateral to secure agricultural credit, making it difficult for them to access the funding they need.
4. Seasonal fluctuations: Agricultural production is often seasonal, which can make it difficult for farmers to repay loans on a regular schedule.
5. Inadequate financial management: Some farmers may lack the financial management skills necessary to effectively manage agricultural credit.
6. Political interference: Agricultural credit may be subject to political interference, which can lead to problems with repayment and other issues.

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(a) The laws of Mendel are the basic principles of inheritance that describe how traits are passed down from one generation to the next. They are as follows:

1. Law of segregation: Each individual has two copies of each gene, which separate during gamete formation so that each gamete carries only one copy of each gene.

2. Law of independent assortment: The inheritance of one gene does not affect the inheritance of another gene, so different traits are inherited independently of each other.

3. Law of dominance: In a pair of contrasting traits, one allele is dominant and the other is recessive. An organism with one dominant allele and one recessive allele will express the dominant trait.

(b) Advantages of introduction and selection in crop improvement:

1. Introduction:

   1. Genetic diversity: Introduction of new plant varieties can increase genetic diversity in a crop population, which can improve crop yield and resistance to pests and diseases.
   2. Adaptation: Introduced plant varieties may be better adapted to local growing conditions, such as climate or soil type, which can increase crop productivity.
   3. Hybridization: Introduced plant varieties can be used in hybridization programs to develop new varieties with desirable traits.

2. Selection:

   1. Improved traits: Selection allows for the improvement of specific traits in a crop population, such as yield, disease resistance, or quality.
   2. Reduced genetic variability: Selection can reduce the genetic variability in a crop population, which can improve the uniformity and predictability of the crop.
   3. Cost-effective: Selection is a relatively simple and cost-effective method of crop improvement that can be implemented by farmers or breeders.

Disadvantages of introduction and selection in crop improvement:

1. Introduction:

   1. Genetic contamination: Introduction of new plant varieties can lead to genetic contamination of local varieties, which can negatively affect the genetic diversity of the crop population.
   2. Adaptation issues: Introduced plant varieties may not be well adapted to local growing conditions, which can result in poor crop performance.
   3. Invasive species: Introduced plant varieties may become invasive and outcompete local plant species, leading to ecological imbalances.

2. Selection:

   1. Narrow genetic base: Selection can reduce the genetic variability in a crop population, which can lead to a narrow genetic base and increase susceptibility to pests and diseases.
   2. Time-consuming: Selection can be a time-consuming process that may require multiple generations to achieve the desired results.

Antwortdetails

1. Poor Infrastructural Development: Agriculture in Nigeria is plagued by inadequate infrastructural development. This includes poor road networks, lack of storage facilities, and unreliable power supply. The solution to this problem is to invest in the development of infrastructure. The government should prioritize the construction and rehabilitation of roads, provide access to storage facilities, and ensure that power supply is consistent.

2. Climate Change: Nigeria's agricultural sector is highly vulnerable to the impacts of climate change. Erratic rainfall patterns and increased temperatures pose a significant threat to crop production. One solution is to promote climate-smart agricultural practices that can help farmers adapt to changing weather patterns. These practices include soil conservation, water harvesting, and planting drought-resistant crops.

3. Land Tenure System: Nigeria's land tenure system is highly fragmented and has been a major constraint to agricultural development. The solution is to create a centralized land registry to simplify land ownership and transfer processes. This will help reduce the incidence of land disputes and encourage more private investment in agriculture.

4. Lack of Access to Credit: Smallholder farmers in Nigeria often lack access to credit, which limits their ability to invest in their farms. One solution is to establish agricultural credit facilities that provide farmers with affordable credit. This can be done through partnerships with banks or microfinance institutions.

5. Poor Market Access: Many smallholder farmers in Nigeria struggle to access markets for their produce. This is due to a lack of transportation infrastructure and poor market linkages. The solution is to establish farmer cooperatives that can aggregate produce and negotiate better prices with buyers. Additionally, the government can invest in market infrastructure such as cold storage facilities and transportation networks.

6. Inadequate Extension Services: Extension services are critical to agricultural development as they provide farmers with technical assistance and advice. In Nigeria, extension services are often inadequate, and this limits farmers' ability to adopt new technologies and practices. The solution is to invest in the recruitment and training of extension workers. Additionally, digital technologies such as mobile phones and the internet can be used to provide farmers with access to extension services.

7. Inefficient Input Delivery System: Access to quality inputs such as seeds and fertilizers is critical to agricultural productivity. However, the delivery system in Nigeria is often inefficient, and farmers have difficulty accessing inputs. The solution is to establish a centralized input delivery system that provides farmers with affordable and high-quality inputs.

8. Pests and Diseases: Pests and diseases are a major constraint to agricultural development in Nigeria. This is due to a lack of effective pest and disease management strategies. The solution is to promote the use of integrated pest management (IPM) strategies that combine the use of biological, cultural, and chemical controls. Additionally, farmers should be trained on how to identify and manage pest and disease outbreaks.

Overall, addressing these challenges will require a concerted effort from the government, private sector, and civil society organizations. However, with the right policies and investments, Nigeria's agricultural sector has the potential to drive economic growth, reduce poverty, and ensure food security for its citizens.