WAEC SSCE - Agricultural Science - 2002

Maelezo ya Majibu

Maelezo ya Majibu

Maelezo ya Majibu

Excessive nitrogen application on maize plants can have different effects depending on the stage of growth and the level of nitrogen applied. However, in general, the most common effect is high vegetative growth with low yield. This is because excess nitrogen encourages the plant to produce more leaves and stems at the expense of grain production. This phenomenon is commonly known as "luxury consumption" and can lead to taller, bushier plants that have a reduced ability to produce grains. Therefore, while nitrogen is essential for plant growth and development, excessive application can lead to negative consequences for maize production.

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Rabbits are usually kept in special cages known as hutches. These hutches are made with wire mesh, wood, or plastic, and are designed to provide a comfortable and safe living environment for the rabbits. Hutches are raised off the ground to prevent predators from attacking the rabbits, and they also provide good ventilation to help regulate the temperature and humidity levels. Additionally, hutches are designed to allow for easy cleaning and maintenance, which helps to promote good health and hygiene for the rabbits.

Maelezo ya Majibu

Maelezo ya Majibu

Animal power, which is the use of animals such as oxen, horses, or donkeys, is often used on the farm for ploughing. Ploughing is the process of turning over the soil to prepare it for planting, and animals can provide the necessary pulling power to operate a plough. While animal power can also be used for other activities such as harvesting, spraying, or planting, ploughing is often the most common use of animal power on the farm.

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The important forage crop in West Africa is giant star grass. Giant star grass is a highly productive perennial grass with high crude protein content and digestibility. It is an excellent forage crop for livestock and is commonly used in West Africa for grazing and cut-and-carry systems. It is also resistant to drought and can tolerate low soil fertility, making it a valuable crop for farmers in the region.

Maelezo ya Majibu

Maelezo ya Majibu

An acidic soil can be neutralized by the addition of wood ash. Wood ash contains calcium, magnesium, and potassium compounds, which can react with the acidic soil and neutralize it. The reaction forms water and salts, which help to increase the soil's pH, making it less acidic. Additionally, wood ash also contains nutrients such as phosphorus and potassium, which are essential for plant growth. However, it is important to note that excessive use of wood ash can lead to an alkaline soil, which is also not ideal for plant growth.

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Subsistence agriculture involves the production of food crops and/or livestock for consumption by the farmer and their family. It is characterized by the use of traditional farming practices and low levels of technology and capital inputs. The main goal of subsistence agriculture is to provide food and other basic necessities for the family, rather than producing for sale or export. It typically relies heavily on family labour, with little or no mechanization. Subsistence agriculture is prevalent in many developing countries and in rural areas of developed countries.

Maelezo ya Majibu

Maelezo ya Majibu

Among the given options, the most flexible and adaptable source of farm power is human power. Human power refers to the use of human labor to perform various farm operations like planting, weeding, harvesting, and transportation of crops. It is flexible because human labor can easily adapt to different farm conditions and tasks. For instance, a person can switch from weeding to planting or harvesting without requiring additional equipment or training. Human power is also adaptable because it can be used in different types and sizes of farms, from small family farms to large commercial farms. Additionally, human power does not require fuel or machinery, making it a cost-effective option for small-scale farmers. Therefore, human power is the most flexible and adaptable source of farm power among the given options.

Maelezo ya Majibu

Maelezo ya Majibu

The source of water that is least useful for irrigation purposes is the sea. This is because seawater has high salinity levels which can damage crops and soil, making it unsuitable for irrigation. The high salt levels can cause the soil to become saline, making it difficult for crops to absorb water and nutrients, and eventually leading to crop failure. Therefore, while seawater can be used for other purposes such as desalination, it is not a suitable source of water for irrigation.

Maelezo ya Majibu

Maelezo ya Majibu

The daily maintenance practice carried out on a disc harrow is cleaning the soil off the disc. This is because during its operation, the disc harrow cuts through the soil, and soil and debris can accumulate on the discs and impede its efficiency. Therefore, it is essential to clean the disc harrow after each use to ensure that the discs are free of soil and debris for optimal performance.

Maelezo ya Majibu

Maelezo ya Majibu

An advantage of mechanization is that it allows for the carrying out of many farm operations with ease. Mechanization involves using machines and equipment to perform tasks that were traditionally done by hand. With mechanization, farmers can cover more ground and complete tasks more quickly, efficiently, and accurately. This can increase productivity and reduce labor costs. Additionally, mechanization can also help to reduce the physical strain on farmers and farm workers, leading to improved working conditions.

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When soils are poorly drained, the air content of the soil is reduced. Poorly drained soils are saturated with water which fills up the pores between the soil particles. As a result, the air content in the soil is reduced, leading to anaerobic conditions that can negatively affect plant growth. Oxygen is required for the respiration of roots and soil microorganisms, and without it, the rate of decomposition can be slowed down. Additionally, anaerobic conditions can lead to the production of toxic substances in the soil that can inhibit plant growth. Therefore, proper drainage is important for maintaining a healthy soil environment for plants to grow.

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Poor management may cause fish diseases in a pond. Poor management practices such as overfeeding, overcrowding, poor water quality management, lack of proper aeration and filtration systems, and improper use of chemicals can lead to stress in fish, making them more susceptible to diseases. The stress may weaken the immune system of the fish, making them more vulnerable to infections and diseases.

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The major problem of grains storage in the rain forest zone of West Africa is high humidity. This is because the high humidity in the environment provides a suitable condition for microorganisms, insects, and pests to grow, thereby leading to spoilage of the grains. The moisture content in the grains also increases due to the high humidity, which can lead to germination and spoilage. Therefore, controlling the humidity level during storage is crucial to prevent spoilage and preserve the quality of the grains.

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The sugar that is most commonly found in the blood of animals is glucose. Glucose is a monosaccharide, which is a type of carbohydrate that provides energy to cells. It is the primary source of energy for the brain, nervous system, and red blood cells. Glucose is produced during digestion of carbohydrates and is transported in the bloodstream to provide energy for various metabolic processes in the body. It is also stored in the liver and muscles as glycogen.

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A sow, which is a female pig, is normally expected to farrow (give birth to piglets) twice a year. This is because the gestation period of a sow is about 3 months, 3 weeks, and 3 days, which means that a sow can have two litters of piglets in a year. However, the number of piglets in each litter can vary depending on various factors such as the breed of the sow, the health of the sow, and the quality of the feed.

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A fixed factor of production in a crop production enterprise refers to a factor that remains constant regardless of the level of output. In this context, the size of the land is an example of a fixed factor of production because it is a fixed resource that cannot be increased or decreased in the short run. For instance, a farmer cannot quickly acquire additional land to produce more crops within a season. As such, the farmer must plan and manage the available land effectively to optimize crop yield and returns on investment.

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When the government provides subsidies in agriculture, it means that the government is giving financial assistance to farmers in the form of reduced prices on farm inputs like fertilizers, seeds, and machinery. This is done to make farming more affordable for farmers and to encourage them to produce more crops. The aim is to increase agricultural productivity and output, which would, in turn, lead to more food being produced for the population. Therefore, option A "farm inputs are made available to farmers at reduced prices" is the correct answer.

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Nitrogen is an essential nutrient for plant growth and development. However, plants cannot directly use atmospheric nitrogen gas. Instead, they take up nitrogen through their roots in the form of nitrate ions (NO3-) or ammonium ions (NH4+). Nitrate ions are the most common form of nitrogen taken up by plants from the soil. They are formed through the oxidation of ammonium by soil bacteria, and can be easily absorbed by plant roots. Therefore, the correct answer to the question is "nitrate ion".

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Maelezo ya Majibu

Parturition in farm animals marks the end of gestation. Gestation refers to the period of pregnancy when the young one is developing inside the mother's womb. Parturition, also known as giving birth, is the process of expelling the young one from the mother's body at the end of gestation. Once the young one is born, the mother starts lactating, and a new cycle begins.

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Selection and hybridization are methods of animal improvement. Animal improvement refers to the techniques or processes used to enhance the genetic makeup of livestock, such as selecting animals with desirable traits and breeding them together to produce offspring with even better characteristics. Selection involves choosing animals with desirable traits and breeding them to pass on those traits to their offspring, while hybridization involves crossing different breeds or species to produce offspring with the best characteristics of both parents. These methods help to improve the productivity, health, and quality of livestock, and can ultimately lead to increased profits for farmers.

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Encouraging afforestation in the arid regions of West Africa is most important to serve as windbreak. This is because the arid regions of West Africa experience strong winds, which can lead to soil erosion, damage to crops, and loss of topsoil nutrients. Afforestation, which involves planting trees and other vegetation, can help to break the force of the wind, reduce soil erosion, and help to retain soil moisture. The trees also provide shade, which can help to reduce the surface temperature of the soil and create a more suitable microclimate for plant growth. Additionally, the trees provide habitats for birds and other wildlife, which can help to maintain ecological balance in the area.

Maelezo ya Majibu

Maelezo ya Majibu

Maelezo ya Majibu

Sudden death without any visible sign of sickness is the symptom that indicates anthrax disease. Anthrax is a bacterial disease caused by Bacillus anthracis, which can affect both humans and animals. It is known to cause sudden death in animals without any visible signs of sickness, making it a dangerous disease that requires immediate attention. The other options listed are not typical symptoms of anthrax disease. Persistent coughing may be indicative of respiratory infections or diseases, abortion in the seventh month of gestation could be caused by several factors, and prolonged diarrhea may be a sign of gastrointestinal disorders.

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To calculate the interest on the loan, we use the formula: Interest = Principal x Rate x Time Where Principal is the amount borrowed, Rate is the interest rate, and Time is the duration of the loan. In this case, the Principal is N120,000.00, the Rate is 9% or 0.09 in decimal form, and the Time is one year. So, Interest = N120,000.00 x 0.09 x 1 Interest = N10,800.00 Therefore, the interest to be paid on the loan is N10,800.00. Option A is the correct answer.

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The process of inducing root development on portions of stems still attached to the parent plant is known as layering. This is a method of propagating new plants from existing plants. In layering, a portion of the stem of a plant is bent down and partially buried in the soil, while still attached to the parent plant. Roots will grow from this buried portion of the stem, and once the roots are well established, the new plant can be separated from the parent plant and grown independently.

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The most important factor that limits agricultural production in West Africa is rainfall. This is because most of West Africa is located within the tropics and experiences a wet-dry climate. The rainy season is relatively short, lasting only a few months, while the dry season is long and severe. Therefore, farmers rely heavily on rainfall for crop production, and when there is insufficient rainfall, crop yield is greatly reduced, resulting in food insecurity. Additionally, unpredictable rainfall patterns, as a result of climate change, further exacerbate the problem of limited agricultural production in the region.

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Weeds which produce light and numerous seeds are normally dispersed by wind. This is because the seeds of such weeds are lightweight and often come equipped with structures that help them be carried by the wind over long distances. As the wind blows, it carries the seeds away from the parent plant and disperses them in different locations, allowing the weed to spread and colonize new areas. This method of seed dispersal by wind is known as anemochory.

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Foot and mouth disease is caused by a virus. The virus can affect cloven-hoofed animals such as cattle, sheep, pigs, goats, and deer, and can cause fever and blister-like sores on the tongue, lips, and hooves. The disease can lead to decreased milk production in cows and weight loss, which can result in economic losses for farmers. It is highly contagious and can spread rapidly among livestock, making it a significant concern for animal health officials.

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Farm accounts are financial records of all the farm income, expenses, and profits. These records help the farmer to manage the farm as a business by tracking expenses and income, identifying areas of profitability and loss, and making informed decisions about production, marketing, and financial management. By keeping records, farmers can identify areas where costs can be reduced and profits increased, and can also make informed decisions on whether to expand or contract their farming operations. Furthermore, by tracking expenses, farmers can budget their resources effectively and adopt modern farming techniques that will maximize their profits.

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Grit is mostly found in the gizzard of poultry. The gizzard is a muscular part of the digestive tract of birds that is responsible for grinding and breaking down food. It contains small stones, or grit, which are swallowed by birds and help to mechanically break down the food as it passes through the gizzard. The proventriculus is a glandular stomach that secretes digestive enzymes, while the cloaca is the common opening through which waste products and eggs are expelled. The rectum is the final part of the digestive tract where feces are stored before being excreted.

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The effect that is not a consequence of 'introduction' in crop improvement is "hampering the growth of local varieties." When a new crop is introduced, it may have various benefits, such as higher yield, improved quality, and faster maturity than local varieties. However, it does not necessarily mean that it will harm the growth of local varieties. In fact, sometimes the introduced crop can bring new genetic traits that can be crossed with the local variety to produce even better varieties. Therefore, the statement that "introduced crops hamper the growth of local varieties" is not a valid effect of crop introduction.

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Sexual propagation involves the use of seeds. In this method, plants are propagated through the union of male and female reproductive cells, resulting in the development of seeds. The seeds can be collected, stored and sown in order to grow new plants with similar characteristics to the parent plant. This method is commonly used for crops, vegetables, and fruit trees. Sexual propagation has the advantage of producing plants that are genetically diverse, which may increase their resistance to diseases and pests.

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The correct answer is "unlimited ability to digest fibre". Pigs are known for their high feed conversion rate, fast growth rate, and high prolificacy. However, unlike ruminants like cows and sheep, pigs have a limited ability to digest fibre. This is because they have a simple stomach and lack the specialized microorganisms necessary to break down complex carbohydrates in fibrous materials like hay and straw. As a result, pigs require a diet that is high in energy and low in fibre to support their growth and production.

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Maelezo ya Majibu

Maelezo ya Majibu

The crop that requires shade in the early stages of its growth in the field is cocoa. Cocoa plants need to be grown in partial shade in the early years of growth, which helps them to establish well and protect them from the direct sun. As they mature, the shade can be gradually reduced until the plants are fully exposed to the sun. Coconut, banana, and cotton do not require shade during their early stages of growth.

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During the process of photosynthesis, plants take in carbon dioxide from the atmosphere and use it along with water and sunlight to produce glucose and oxygen. This process occurs in the chloroplasts of plant cells and is essential for the growth and development of plants. As a result of photosynthesis, carbon is fixed into organic molecules, which are used as a source of energy for the plant and other organisms that consume it. Therefore, the correct answer is photosynthesis.

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The most unreliable source of power supply to the farm among the options listed is wind. This is because wind energy is highly dependent on weather conditions, and its supply can vary greatly from day to day or even hour to hour. Wind turbines can only generate electricity when there is sufficient wind speed, and if the wind is too strong, the turbines have to be shut down to avoid damage. In addition, wind power generation requires large initial investments and can be affected by issues such as noise pollution and bird mortality. On the other hand, electricity, animal, and machine power can be more reliable as they are not as affected by weather conditions and can be controlled more easily.

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When N'dama cows are mated by Muturu bulls, the system of breeding that is practiced is crossbreeding. Crossbreeding is the process of mating individuals from two different breeds or populations. In this case, N'dama cows and Muturu bulls belong to different breeds. Crossbreeding is usually done to produce offspring with desirable traits that are not present in the parent breeds. The offspring of crossbreeding are usually more vigorous and healthy than their parents, a phenomenon known as hybrid vigor or heterosis.

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Mosaic disease affects cassava and tobacco. It is a viral disease that causes a mosaic-like pattern on the leaves of infected plants. The affected leaves usually become distorted, stunted and mottled with light and dark green patches. The virus is transmitted by insects, such as whiteflies and aphids, and also through the use of infected plant materials for propagation. The disease can cause significant yield losses in affected crops, and control measures such as the use of resistant varieties and insecticides are often recommended.

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The primary purpose of establishing wildlife reserves is to prevent the extinction of wild animals. Wildlife reserves are established to protect wild animals and their habitats from human encroachment and exploitation. By designating an area as a wildlife reserve, it becomes illegal to hunt, capture, or kill animals within its boundaries, thus providing a safe space for them to thrive and reproduce. The reserves also allow scientists to study the behavior and ecology of different species, which can help in developing strategies for their conservation. Overall, wildlife reserves play a vital role in maintaining the biodiversity of our planet and ensuring that future generations can enjoy the beauty and diversity of our natural world.

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Plant quarantine regulations are enforced to prevent the introduction of foreign pests and diseases. This is done to protect domestic crops and the environment from the harmful effects of invasive species that could cause economic and ecological damage. These regulations are put in place to ensure that plants and plant products that enter a country or region are free from pests and diseases, or are subjected to appropriate measures to control or eradicate any such pests and diseases. This helps to maintain the health and productivity of agricultural crops and preserves biodiversity.

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The growing of both forest trees and arable crops simultaneously on the same piece of land is called the taungya system. This system involves planting forest trees on a piece of land, and then, during the early stages of forest growth, intercropping with annual crops. The crops help to shade the trees, control weeds and increase the fertility of the soil. As the trees grow and mature, they are thinned to create more light for the remaining trees, which eventually form a dense forest canopy. The taungya system is often used in tropical countries as a way to provide both food and timber resources while also conserving the environment.

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Agricultural extension programme promotes the practical application of useful agricultural information to farmers. It is a service that provides farmers with knowledge and skills to improve their agricultural practices and increase productivity. The goal of extension programs is to disseminate research-based information to farmers, helping them adopt new technologies, management practices, and marketing strategies. The programme aims to improve the standard of living of farmers by providing education and training that enhances their farming activities.

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The correct answer is "causes plant roots to wilt". Waterlogging is a condition in which the soil becomes saturated with water, leading to the reduction or lack of oxygen available to plant roots. This situation can affect plant development by inhibiting the activities of microorganisms that are essential for nutrient availability, thereby reducing nutrient uptake and leading to the eventual death of plant roots. Waterlogging also encourages leaching, which is the loss of nutrients from the soil, leading to reduced crop yield. The condition does not cause plant roots to wilt. Instead, the roots become swollen and may turn brown or black due to lack of oxygen, leading to plant death.

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Capillarity is the ability of water to move upwards through soil against the force of gravity. The rate of capillarity in soil is influenced by the size of the soil particles. Smaller soil particles have greater surface area per unit volume, which increases the forces of attraction between the water and the soil particles, resulting in higher capillarity. Therefore, capillarity is highest in soil with smaller particles, such as clay. Thus, the correct answer is clay.

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