JAMB UTME - Agricultural Science - 2021

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The characteristic symptoms of mosaic disease of crops can be observed on the leaves of plants. This disease is caused by viruses and is characterized by the appearance of yellow or greenish-yellow patches or mottling on the leaves. The leaves may also become curled, stunted or distorted. This discoloration and distortion is referred to as the "mosaic" pattern, hence the name of the disease. The virus can spread quickly throughout the plant, affecting its overall growth and yield. In some cases, the fruits of the plant may also be affected.

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Layer's ration contains more limestone than grower's ration because limestone supplies sufficient minerals to layers for shell formation. Layers are chickens that are specifically raised for egg production, while growers are chickens that are raised for meat production. The composition of the feed for these two types of chickens is different, with layer's ration containing more calcium in the form of limestone. Calcium is an essential mineral for the formation of eggshells, and it is important for layers to have a constant supply of calcium in their diet. The higher level of limestone in layer's ration helps to ensure that the layers have access to the calcium they need for strong and healthy eggshells. On the other hand, growers do not require as much calcium in their diet as layers, so their ration contains less limestone.

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The study of insect pests of crops is called entomology. Entomology is the scientific study of insects, including their biology, behavior, evolution, and ecological relationships. Within entomology, there is a subfield that focuses specifically on insects that cause harm to crops, livestock, and other agricultural products. This subfield is called agricultural entomology and it focuses on the study of insect pests and their management. Pathology is the study of diseases and their causes, while agronomy is the science and technology of producing and using plants for food, fuel, and other products. Synecology is the study of ecological communities and their interactions. So, the answer to the question is entomology.

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Subsistence agriculture is characterized by small farm holdings and the production of food for the farmer's own use and consumption. Subsistence agriculture is a type of farming that is practiced on a small scale and is focused on providing food and basic necessities for the farmer and their family, rather than producing crops for sale or trade. Subsistence farmers typically cultivate small plots of land and use simple tools and techniques to grow crops and raise animals. In contrast, large scale agriculture is characterized by the use of machines and intensive use of inputs, such as fertilizers and pesticides, to maximize production and increase profits. While subsistence agriculture can provide food security for the farmer and their family, it can also result in low yields and limited economic opportunities. On the other hand, large scale agriculture can be more efficient and profitable, but can also lead to environmental degradation and social inequalities.

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The horizon of a soil profile that encourages the greatest level of microbial activity is the A horizon. Soil horizons are defined layers in a soil profile, each with its own distinct physical and chemical properties. The A horizon, also known as the topsoil, is the topmost layer of the soil profile and is typically rich in organic matter, nutrients, and water. This layer is also where the majority of soil microbes, such as bacteria, fungi, and other microorganisms, are found. The B horizon, also known as the subsoil, is below the A horizon and is typically more compact and less porous than the A horizon. It contains relatively low levels of organic matter and is not as conducive to microbial activity as the A horizon. The C horizon is the layer of soil material that is below the B horizon and is composed of partially weathered rock fragments and mineral particles. This layer typically has low levels of organic matter and is not as conducive to microbial activity as the A horizon. The D horizon is not present in all soils and is typically composed of consolidated bedrock. This layer is not conducive to microbial activity as it is typically inhospitable to life due to its lack of water and organic matter. So, the answer to the question is the A horizon.

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The gestation period is the time between conception and parturition. Gestation is the period of pregnancy in mammals, during which a fertilized egg develops into a fetus and prepares for birth. The gestation period is the length of time from when the sperm fertilizes the egg to when the animal gives birth. This period can vary greatly among different species, ranging from a few weeks in some small mammals to over a year in elephants and whales. The time of fusion of the sperm and the egg is referred to as fertilization. The time of release of the ovum from the ovary is referred to as ovulation. The time of birth of the young animal is referred to as parturition.

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Foot and mouth disease is a highly contagious viral disease that affects cattle, as well as other cloven-hoofed animals such as pigs, sheep, and goats. The most common symptoms of foot and mouth disease in cattle include excessive production of saliva, sores on the feet and tongue, and lameness. However, blood-stained diarrhea is not typically a symptom of foot and mouth disease in cattle. While diarrhea can occur as a result of other diseases or health conditions, it is not a common symptom of foot and mouth disease. If a farmer notices blood in the diarrhea of their cattle, it is important to seek veterinary advice to determine the underlying cause and provide appropriate treatment.

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The condition in which a gene does not manifest observable characteristics in the presence of its dominant allele is known as recessiveness. In genetics, alleles are different versions of a gene. When an organism has two different alleles for a particular gene, one allele will be dominant and the other will be recessive. The dominant allele masks the expression of the recessive allele, so that the observable characteristics associated with the dominant allele are expressed in the organism. A recessive gene is only expressed when an organism has two copies of that gene, one from each parent. If an organism has one dominant allele and one recessive allele, the dominant allele will mask the expression of the recessive allele. So, the answer to the question is recessiveness. Mutation refers to a change in the DNA sequence of a gene, while dominance refers to the relationship between two alleles, where one allele masks the expression of another. Homozygosity refers to the condition in which an organism has two identical alleles for a particular gene.

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The practice of mating closely related animals is called inbreeding. Inbreeding is when two animals that are closely related, such as siblings or parent and offspring, are bred together. This increases the likelihood that their offspring will have similar traits and characteristics because they share many of the same genes. While inbreeding can lead to the expression of desirable traits, it can also increase the risk of genetic disorders and other health problems. For this reason, many breeders prefer to use outbreeding, or mating animals that are not closely related, to promote genetic diversity and reduce the risk of health problems in their offspring.

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Ginning is a method of processing cotton. Ginning is the process of separating the cotton fibers from the seeds in cotton crops. The cotton fibers are used to make textiles, while the cotton seeds are used for oil production. Ginning is done by passing the cotton through a machine called a cotton gin, which uses a combination of mechanical and manual processes to separate the fibers from the seeds. Cocoa, oil palm, and palm kernel oil are not processed by ginning. Cocoa is a crop that is used to make chocolate, while oil palm is a type of palm tree that is grown for its oil-rich fruit. Palm kernel oil is derived from the seeds of the oil palm tree and is used in a variety of food and industrial products. So, the answer to the question is cotton.

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A subsidy in agricultural enterprise is a financial benefit provided by the government to support the agricultural sector. It can take many forms, but one example is the supply of fertilizers to farmers at a reduced price. In this scenario, the government reduces the cost of fertilizers for farmers by providing subsidies, making it more affordable for them to purchase the necessary inputs to grow their crops. This helps to improve the overall productivity and competitiveness of the agricultural sector, and can have a positive impact on the lives of farmers and the local economy. The other options listed (borrowing of money from a thrift society, provision of money to farmers through commercial banks, and provision of services through cooperative societies) are not considered subsidies in the strictest sense. However, they may still provide valuable support to farmers and the agricultural sector in other ways.

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An advantage of an extensive system of rearing goats is low labor requirement. This means that in an extensive system, goats are allowed to graze and forage for their own food in a natural environment, with minimal human intervention. This can result in a lower cost of production as there is less need for expensive feed and fewer inputs required for maintenance. Additionally, this system can also be less time-consuming for the farmer, as there is less need for daily chores such as feeding and cleaning.

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The following are necessary operations in maize cultivation except nursery practices. Maize cultivation involves a number of steps, including preparation of the soil, planting, weeding, thinning, and fertilizer application. Weeding is important to remove competing vegetation that can reduce the growth and yields of the maize crop. Thinning involves removing excess plants in order to allow the remaining plants to grow to their full potential. Fertilizer application provides the plants with essential nutrients that they need to grow and produce a healthy crop. Nursery practices refer to the process of growing plants in a protected environment, such as a greenhouse or a nursery, before transplanting them to the field. While nursery practices can be important for some crops, they are not a necessary operation in maize cultivation. Maize can be directly seeded into the field and grown to maturity without the need for a separate nursery stage.

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Food shortage can be minimized by improving agricultural practices and increasing food production. This can be achieved by implementing efficient pest control services, using modern techniques for crop cultivation, and providing farmers with the necessary resources and support. Additionally, reducing food waste and preventing hoarding of food supplies can also help to minimize food shortages. However, it's important to note that natural hazards such as droughts, floods, and extreme weather conditions can impact food production and lead to food shortages. The illegal exportation of farm produce can also contribute to food shortages in certain regions by reducing the available food supplies in those areas.

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The option that does not describe the effect of practicing crop rotation is "adding humus to the soil." Crop rotation involves planting different crops in a specific sequence in a certain area over time. The purpose of this is to maintain and improve soil fertility, control soil erosion, and prevent the build-up of pests and diseases. By rotating crops, the soil is given a chance to rest and recover nutrients that were taken away by previous crops, leading to healthier soil and better crop growth. On the other hand, adding humus to the soil involves adding organic matter such as compost, leaves, or manure to the soil. This helps to improve soil structure, water retention, and nutrient availability. While adding humus to the soil can complement the effects of crop rotation, it is not a direct result of practicing crop rotation.

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The hormone responsible for milk let down in female farm animals is oxytocin. Oxytocin is produced by the pituitary gland and is released into the bloodstream when the animal is ready to nurse its young or be milked. When oxytocin is released, it stimulates the contraction of the muscles in the mammary glands, causing the milk to flow from the teat. This hormone plays a crucial role in the lactation process and is essential for providing nourishment to the young in many species of mammals, including cows, goats, and sheep. The release of oxytocin can also be triggered by the stimulation of the teats, such as when a calf or kid suckles or when a milker applies a milking machine to the teat, making it a key player in the dairy industry.

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The system in which a farmer uses a piece of land for a period and abandons it for another land is called "shifting cultivation". In this system, a farmer will clear a piece of land for farming, use it for a few seasons until the soil becomes less fertile, and then move on to another piece of land and repeat the process. This allows the abandoned land to recover its fertility and biodiversity. Shifting cultivation is often used by small-scale farmers in tropical regions where the soil is less fertile and where there are few other options for agriculture.

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The most common factor affecting land use is population pressure. This means that as the number of people in an area increases, there is a greater demand for land to be used for residential, commercial, and industrial purposes. This pressure can lead to changes in land use, such as the conversion of farmland to urban areas, deforestation, and the development of new infrastructure. In simple terms, as the population grows, the demand for land increases, and this affects how the land is used.

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The main processes involved in the marketing of cotton do not include wedding. Wedding is not a process that is typically associated with the marketing of cotton. The marketing of cotton typically involves several key processes, including processing, grading, and packaging. Processing involves cleaning and preparing the cotton fibers for use in various products. This may include spinning the cotton into yarn or thread, and weaving or knitting the cotton into fabric. Grading involves evaluating the quality of the cotton fibers and sorting them into different grades based on factors such as length, strength, and color. This helps to ensure that the cotton fibers are used in the most appropriate applications and that customers receive the best quality products. Packaging involves packaging the cotton fibers or products made from cotton into bags or other containers for storage and transportation. This helps to protect the cotton from damage and contamination during transit and storage, and makes it easier for customers to handle and use the cotton in their own operations.

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The process in crops that is not sensitive to daylength is branching. Daylength, or photoperiod, is the length of time that a plant is exposed to light in a 24-hour period. Many crops, such as soybeans and corn, are sensitive to daylength and the changes in the amount of daylight they receive can trigger different physiological processes, such as flowering, fruiting, and growth. However, branching, or the formation of new shoots and stems from the parent plant, is not a process that is sensitive to daylength. Branching occurs as a result of other factors such as plant hormones, environmental conditions, and genetics. So, the answer to the question is branching.

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In subsistence agriculture, surplus produce is small and savings are not made. Subsistence agriculture is a type of agricultural system in which farmers grow food primarily for their own consumption and for the consumption of their families and communities. In subsistence agriculture, farmers typically have limited resources and technology, and the focus is on producing enough food to meet basic needs, rather than producing a surplus for sale or trade. As a result, the surplus produce from subsistence agriculture is typically small, and farmers do not have the resources or market access to make savings or investments. Instead, they focus on producing enough food to feed themselves and their families. Farm sizes in subsistence agriculture can vary, and may range from small plots of land to larger holdings. The main focus is on producing enough food to meet basic needs, rather than maximizing production and profits. So, the answer to the question is surplus produce is small and savings are not made.

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The alternate heating and cooling of rocks can result in a process called thermal stress. When rocks are subjected to changes in temperature, the different layers of the rock expand and contract at different rates. This can cause stress on the rock and over time, it can lead to cracking and breaking, a process known as fragmentation. This can happen as a result of volcanic activity, tectonic activity, or weathering and erosion. The rocks can also undergo cycles of heating and cooling and this can result in the formation of fractures and joints. In some cases, the heat can be so intense that it causes the rocks to melt, resulting in the formation of magma and new igneous rocks.

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The exception to the methods of preserving fish is boiling. Boiling is a method of cooking fish and does not preserve it for a long period of time. The other methods listed, such as drying, smoking, and salting, are methods of preserving fish by removing moisture and adding salt to prevent the growth of bacteria and other microorganisms that can cause spoilage. These methods can keep fish fresh for several weeks or months, depending on the method used and the conditions under which the fish is stored.

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IITA stands for International Institute of Tropical Agriculture. It is an international research organization that focuses on agricultural development in tropical regions, particularly in Africa. The goal of IITA is to help farmers in these areas improve their yields and livelihoods by providing them with better seeds, technologies, and knowledge. The institute conducts research and development work in various areas of agriculture, including plant breeding, crop production, and agroforestry. It works with government agencies, universities, and other organizations to help farmers in tropical regions grow more food and improve their lives.

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The most versatile source of farm power in West Africa is likely to be animal power, specifically using oxen or cattle to plow fields and perform other tasks. In many rural areas of West Africa, access to electricity and other modern sources of energy is limited, making it difficult to use more technologically advanced methods like biogas, wind, or water power. However, animals such as oxen or cattle are readily available and can be trained to perform a wide range of tasks on the farm. In addition, animal power is flexible and can be used for a variety of purposes, including plowing, transportation, and even as a source of fertilizer. This versatility makes animal power a valuable asset for farmers in West Africa.

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The salvage value of a tractor can be calculated by subtracting the depreciation value from the initial cost. The initial cost of the tractor is ₦50,000, and the depreciation value after a year of use is ₦10,580. To calculate the salvage value, we subtract the depreciation value from the initial cost: ₦50,000 - ₦10,580 = ₦39,420 Therefore, the salvage value of the tractor after a year of use is ₦39,420.

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The following is not a method of improving rangeland: regular application of fertilizers. Improving rangeland involves managing the land in a way that promotes the growth of desirable vegetation and reduces the impact of undesirable vegetation. One of the methods of improving rangeland is practicing continuous grazing, which involves rotating animals from one area to another to prevent overgrazing and allow the vegetation to recover. Routine and regular weeding involves removing unwanted plants that compete with the desirable vegetation for water, nutrients, and light. Routine reseeding involves replanting desirable vegetation that has been lost due to natural causes or overgrazing. While regular application of fertilizers can be important for improving the quality of cultivated crops, it is not a method of improving rangeland. In many cases, applying fertilizers to rangeland can actually have negative impacts, such as altering the natural balance of the ecosystem and promoting the growth of undesirable vegetation. It is often better to manage rangeland through a combination of grazing management, weed control, and reseeding, rather than applying fertilizers.

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A spade is not a farm surveying equipment. Farm surveying equipment refers to the tools and instruments used to measure and map the land for agricultural purposes. This equipment is used to determine the boundaries and dimensions of a field, the slope of the land, and other physical features that can affect the planning and management of agriculture. The Abney level, compass, and Gunter's chain are all examples of farm surveying equipment. The Abney level is a type of hand-held instrument used to measure angles and slopes. The compass is used to determine direction and to align survey lines. Gunter's chain is a type of measuring tape that is used to measure distances and to lay out survey lines. A spade, on the other hand, is a tool used for digging and removing soil. While a spade can be useful for preparing the soil for planting, it is not typically considered a surveying instrument.