JAMB UTME - Agricultural Science - 2015

The device which would help to stabilize heat in an incubator is the

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The device that would help to stabilize heat in an incubator is a thermostat. A thermostat is a device that senses the temperature in a system and can turn a heating or cooling source on or off to maintain a set temperature. In an incubator, a thermostat can be used to sense the temperature and turn on or off a heat source (such as a heating element) to keep the temperature stable and within a set range. A thermometer is a device used to measure temperature, but it does not have the ability to control the temperature. A hygrometer is used to measure humidity and a barometer is used to measure atmospheric pressure, so neither of these devices would help to stabilize heat in an incubator. Therefore, the answer is a thermostat.

Limitations of farm mechanization in West Africa do not include

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Under the commercial land tenure system, farmers find it difficult to secure loans because

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A regulatory control of diseases in crop production is

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If T represents the gene for tallness while t represents dwarfness. The genotypic ratio of the second filial generation will be

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Which of the following groups of rocks is formed as a result of volcanic eruption?

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The group of rocks that is formed as a result of volcanic eruption is basalt, granite, and pumice. Volcanic eruptions involve the release of hot molten rock, ash, and gas from deep within the earth onto the surface. Basalt is a type of igneous rock that forms when lava cools and solidifies quickly on the earth's surface. Granite, on the other hand, is an intrusive igneous rock that forms when magma cools and solidifies deep within the earth. Pumice is also a volcanic rock that forms from the cooling and solidification of frothy lava. Therefore, basalt, granite, and pumice are all examples of rocks that are formed as a result of volcanic activity.

The weight of a sheep increased from 25kg to 45kg in two months. If the total consumption during the period was 60kg,determine the feed conversion ratio.

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The feed conversion ratio (FCR) is a measure of the efficiency with which an animal converts feed into body weight. To determine the FCR of a sheep that increased its weight from 25kg to 45kg in two months while consuming 60kg of feed, we need to divide the total feed consumption by the weight gain: FCR = Total Feed Consumption / Weight Gain Weight gain = 45kg - 25kg = 20kg FCR = 60kg / 20kg = 3:1 This means that for every 3kg of feed consumed, the sheep gained 1kg in weight. A lower FCR is generally considered more desirable, as it indicates that the animal is converting more of the feed into body weight. In conclusion, the feed conversion ratio for the sheep in this scenario is 3:1, which indicates that for every 3kg of feed consumed, the sheep gained 1kg in weight.

Close to the time of harvesting of cotton, sunshine is needed to ensure the production of boils that are

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The correct sequence for the use of coupled implements for land preparation is

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The correct sequence for the use of coupled implements for land preparation is plough, harrow, and ridger. First, the plough is used to turn over and loosen the soil. This makes it easier to remove weeds and other unwanted material from the soil. Next, the harrow is used to break up large clumps of soil and to level the field. This is important for planting seeds or seedlings, as it helps to ensure that they are evenly distributed across the field and can grow properly. Finally, the ridger is used to create furrows or ridges in the soil. These furrows can be used to plant seeds or to channel water for irrigation. Therefore, the answer is plough, harrow, and ridger in that sequence.

If T represents the gene for tallness while t represents dwarfness. When a tall (TT) crop is crossed with a dwarf (tt) crop, the resultant crop will be

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When a tall (TT) crop is crossed with a dwarf (tt) crop, the resultant crop will be 100% tall, but all of the plants will be heterozygous, meaning they will carry one dominant T allele and one recessive t allele (Tt). This is because the T allele for tallness is dominant over the t allele for dwarfness, so even though the dwarf plant only carries the recessive t allele, the tall plant carries two copies of the dominant T allele. The offspring of this cross, called the F1 generation, will inherit one allele from each parent, resulting in a Tt genotype for all plants. While they will all exhibit the tall phenotype, they will carry the recessive allele for dwarfness and can pass it on to their offspring. If two of these F1 plants are crossed with each other, their offspring (the F2 generation) will show a 3:1 ratio of tall to dwarf plants, with both genotypes (TT, Tt, and tt) present in the offspring.

Which of the following statements about soil organisms is false?

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The statement that "soil with good texture and structure cannot harbour soil microbes" is false. Soil texture and structure can affect the abundance and diversity of soil organisms, but they can still thrive in soils with good texture and structure. In fact, soil organisms depend on the physical structure of soil for habitat and resources such as nutrients, water, and oxygen. Soil texture and structure can affect the availability of these resources, but they do not necessarily exclude soil organisms. The other statements are true: - Soil pH can affect the population of soil organisms. Different organisms have different optimal pH ranges, and changes in pH can alter the balance of soil microbial communities. - Increasing soil organic matter can increase the population of soil living organisms. Organic matter provides a source of energy and nutrients for soil organisms, and can improve the physical and chemical properties of soil that support their growth. - Soil temperature can affect the activities of soil organisms. Like all living things, soil organisms have temperature ranges where they function optimally. Temperature can affect the rates of chemical reactions and the availability of resources such as water and oxygen in soil.

The data for feed consumption and weighing gain of four farm animals labelled P, Q, R and S are shown below.
P-50kg feed consumed and 20kg weight gained Q-90kg feed consumed and 30kg weight gained R-100kg feed consumed and 25kg weight gained S - 150kg feed consumed and 30kg weight gained.

The feed conversion efficiency of the poorest weight gainer is

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Government plays important role in the development of agriculture through the following means except

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Corms, rhizomes and tubers are examples of

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Corms, rhizomes and tubers are examples of underground stems. Underground stems are plant structures that are found below the soil surface and are used for food storage and vegetative reproduction. Corms, rhizomes and tubers are all modified forms of underground stems that have adapted to serve different functions. Corms are short, solid, swollen stems that are used for food storage in some plants. Rhizomes are elongated, horizontal stems that grow underground and can produce new shoots and roots, allowing the plant to spread and reproduce vegetatively. Tubers are swollen, fleshy stems that also serve as food storage structures. They are typically rounded or potato-shaped and grow underground attached to a short stem or stolon. So, to summarize, corms, rhizomes, and tubers are all different types of underground stems that have adapted to serve as food storage structures in plants.

The forest management system which involves the planting of both food crops and forest trees on the same piece of land at the same time is known as

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The forest management system which involves the planting of both food crops and forest trees on the same piece of land at the same time is known as taungya. This is a traditional system that has been used in many tropical countries to sustainably manage forests while also meeting the needs of local communities for food and other resources. In taungya, farmers are allowed to cultivate crops in the forest during the early years of forest regeneration, while also planting tree seedlings. The crops are grown mainly for subsistence and are harvested before the trees grow big enough to shade them out. This system allows for the establishment of a forest cover while also providing food and income for local communities. Taungya has been successful in promoting reforestation and improving the livelihoods of communities in many parts of the world. It is a good example of how sustainable forest management can benefit both people and the environment.

Which of the following crops has a fibrous root system?

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Tomatoes are staked in order to

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Tomatoes are staked in order to prevent rotting of fruits. When tomato plants are left to grow on the ground, their fruits are in direct contact with the soil. This can cause the fruits to rot due to moisture, pests, and fungal diseases. Additionally, tomatoes that are in contact with the ground are more susceptible to damage from insects and other animals. Staking tomatoes involves using a support structure, such as a stake or trellis, to hold up the plant and keep the fruits off the ground. This allows for better air circulation around the plant, which can reduce moisture and prevent the spread of diseases. Staking can also help the plant receive more sunlight, leading to more even ripening of the fruits. In summary, staking tomatoes helps prevent the rotting of fruits by keeping them off the ground and allowing for better air circulation around the plant. It can also lead to more even ripening of the fruits and prevent damage from insects and other animals.

A detrimental effect of bush burning is that it

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One detrimental effect of bush burning is that it destroys soil organic matter. Soil organic matter is a crucial component of soil fertility, as it provides nutrients and helps retain moisture in the soil. When bush burning occurs, the intense heat can burn away the organic matter in the soil, leaving it depleted of essential nutrients and less able to support plant growth. This can lead to decreased crop yields and ultimately, soil degradation. Therefore, bush burning can have negative consequences for both the environment and the livelihoods of people who depend on agriculture.

Which of the following diseases commonly occur during brooding? I. yolk sac infection II. coccidiosis III. fowlpox IV. pullorum

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Sexual maturity in farm animals refers to the point in their development when they are capable of reproducing. This is typically determined by biological factors such as age, genetics, and environmental conditions. Of the options given, breed, sex, and nutrition can all play a role in the timing of sexual maturity in farm animals. For example, certain breeds of animals may reach sexual maturity earlier or later than others, and males and females within a breed may also have different rates of development. Nutrition is also important, as animals that are well-fed and receive adequate nutrients are more likely to reach sexual maturity earlier than those that are malnourished. However, weaning age does not appear to have a significant influence on sexual maturity in farm animals. Weaning is the process of separating young animals from their mother's milk and transitioning them to solid food. While weaning age can affect an animal's growth and overall health, it is not thought to have a direct impact on their sexual development. In summary, while breed, sex, and nutrition can influence the timing of sexual maturity in farm animals, weaning age does not appear to play a significant role in this process.

The following crops will enrich the soil with nitrates except

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Of the crops listed, "exoriepus" is the one that does not enrich the soil with nitrates. The other three crops, "calopogonium," "pueraria," and "centrosema," are leguminous plants and have a symbiotic relationship with nitrogen-fixing bacteria that convert atmospheric nitrogen into nitrates, which can be absorbed by the plant and used for growth. The plant then returns some of the nitrates to the soil, enriching it for future crops.

Which of the following statement is a disadvantage of human power? it

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The disadvantage of human power is that it has low output. This means that humans can only produce a limited amount of power, and this power is not enough to perform some tasks that require high levels of power. For example, tasks such as plowing a large field or lifting heavy loads may be difficult or impossible for a human to do alone. As a result, other sources of power, such as animals or machines, may be needed to supplement or replace human power in order to accomplish these tasks efficiently.

Which of the following factors are causes of deforestation in West Africa? I. expansion of cultivated land II. high population growth rate III. conservation of wildlife in game reserves IV. urban growth

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The causes of deforestation in West Africa are primarily due to the expansion of cultivated land, high population growth rate, and urban growth. These factors are closely interrelated, as population growth leads to increased demand for food, which in turn drives the expansion of cultivated land. Urban growth also contributes to deforestation as cities expand and encroach on surrounding forests. Conservation of wildlife in game reserves is not a cause of deforestation, but rather a strategy to protect and preserve the remaining forested areas. Therefore, the correct answer is option C: I, II, and IV only.

The use of animal traction is limited in the forest zones of West Africa because of the

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The use of animal traction is limited in the forest zones of West Africa mainly because of the presence of tsetseflies. Tsetseflies are insects that carry a parasite which causes a disease called sleeping sickness in both humans and animals. This disease is a major health concern for people and livestock in these areas, and it can spread quickly through the use of animal traction. As a result, people in these areas tend to avoid using animal traction to prevent the spread of the disease and protect their health and the health of their animals.

Poaching is prohibited in game reserves to

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Poaching is prohibited in game reserves to conserve wildlife. Poaching refers to the illegal hunting or killing of wild animals, and it can have a significant impact on wildlife populations. When animals are hunted or killed illegally, it can disrupt the balance of the ecosystem and lead to declines in population numbers. This can also have a negative impact on the overall health of the species, as well as the ecosystem as a whole. In order to protect wildlife populations and conserve their habitats, game reserves often implement measures to prevent poaching. This can include increased patrols and surveillance, stricter penalties for poaching, and education and outreach programs to raise awareness about the importance of conserving wildlife. In summary, poaching is prohibited in game reserves to conserve wildlife and protect them from declines in population numbers.

Agriculture contributes to the economy of West African Countries through the following means except

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Agriculture in West African countries primarily contributes to the economy through the reduction of poverty through job creation, provision of foreign exchange, and supply of raw materials to industries. However, it does not contribute to the economy through the supply of armaments for territorial defense. Agriculture provides employment opportunities for a large number of people in West African countries, thereby reducing poverty. It also generates income from the sale of agricultural products, which can be used to purchase other goods and services, thereby contributing to the overall growth of the economy. Additionally, the export of agricultural products from West African countries to other countries provides a source of foreign exchange, which is crucial for the development of the economy. The foreign exchange earned from agriculture can be used to import goods and technologies that are not available domestically, which can help to improve the overall standard of living. Finally, the supply of raw materials to industries, such as food and beverage, textiles, and cosmetics, also contributes to the economy. These industries process the raw materials into finished products that can be sold locally and internationally, generating income and employment opportunities. In conclusion, while agriculture is a significant contributor to the economy of West African countries, it does not contribute through the supply of armaments for territorial defense.

A sow that is not producing milk after farrowing should be given

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The instrument which enables a surveyor to find the direction of a base line is

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The instrument which enables a surveyor to find the direction of a base line is the "magnetic compass." A magnetic compass is an instrument that uses a magnetized needle to indicate the direction of the Earth's magnetic field. By aligning the compass with the direction of the magnetic field, the surveyor can determine the orientation of a base line, which is a fixed reference line used in surveying. In surveying, a base line is a line of known length and orientation that is used as a reference for making other measurements. It is typically established by measuring between two points with a high degree of accuracy using a tape measure or other measuring instrument. Once the base line has been established, the surveyor can use a magnetic compass to determine its orientation relative to the Earth's magnetic field. Using the magnetic compass, the surveyor can measure the angle between the base line and a reference direction, such as true north or magnetic north. This information can be used to orient other measurements taken during the survey, such as angles between points or distances between points. In this way, the magnetic compass is a critical tool for surveyors in determining the direction and orientation of a base line.

The data for feed consumption and weighing gain of four farm animals labelled P, Q, R and S are shown below.

P -50kg feed consumed and 20kg weight gained Q -90kg feed consumed and 30kg weight gained R -100kg feed consumed and 25kg weight gained S - 150kg feed consumed and 30kg weight gained.

Which of the following must efficient feed converter?

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FCR for P = 20/50=2/5=0.4<br>
FCR for Q = 30/90=1/3=0.33<br>
FCR for R = 25/100=1/4- 0.25<br>
FCR for S = 30/150=1/5=0.2<br><br>
P is correct because P has the highest FCR

Crop rotation decreases the incidence of pests by

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Crop rotation decreases the incidence of pests by breaking the life cycles of pests. By planting different crops in a field over time, pests that rely on a particular crop to survive are deprived of their food source and their life cycle is disrupted. For example, if a field is planted with corn one year and soybeans the next, pests that thrive on corn will not be able to survive in the soybean field, reducing their population. Additionally, rotating crops can help maintain soil fertility, which can improve the health and resilience of crops and make them less susceptible to pest attacks. While crop rotation may also attract pest predators, such as beneficial insects, this is not the primary way in which it reduces pest incidence.

Pineapple is widely propagated using

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Pineapple is widely propagated using suckers. Suckers are small plantlets that develop from the base of the pineapple plant. They can be separated from the mother plant and replanted to produce new, genetically identical plants. This is the most common and efficient way to propagate pineapple plants for commercial cultivation. While pineapple plants can produce seeds, they are generally not used for propagation because they do not produce true-to-type offspring. This means that the resulting plants may not have the desired characteristics, such as fruit quality or disease resistance. Slips and cuttings can also be used to propagate pineapple plants, but they are less commonly used compared to suckers. Slips are shoots that grow from the base of the fruit, while cuttings are sections of the stem. However, these methods are less efficient and may result in plants with less vigor and lower fruit quality compared to plants grown from suckers.

If the recommended spacing for a tree crop is 2.5cm by 4.0m.determine the number of seedlings required to plant a 2 hectare farmland.

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Which of the following factors does not influence the distribution of cattle in West Africa?

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The factor that does not influence the distribution of cattle in West Africa is "light." Cattle need food and water to survive, and in West Africa, the most important factor that influences the distribution of cattle is "rainfall." This is because rainfall directly affects the availability of water and pasture for the cattle to feed on. Areas with high rainfall generally have more abundant vegetation, which provides grazing for the cattle, and a greater supply of water. Diseases also affect the distribution of cattle in West Africa. Some diseases, such as trypanosomiasis (sleeping sickness), are transmitted by tsetse flies and can only be found in areas where the flies are present. As a result, cattle cannot be kept in these areas without being treated with prophylactic drugs or without adopting other strategies to control the disease. Pastures also play a critical role in the distribution of cattle in West Africa. Areas with fertile soils and abundant grasses and shrubs are preferred for grazing. In contrast, areas with poor soil fertility or that have been overgrazed are less favorable for cattle. Light, on the other hand, does not have a direct influence on the distribution of cattle in West Africa. While it is true that cattle require sunlight for growth and metabolism, the intensity and duration of sunlight are fairly consistent across the region, and thus do not vary enough to affect the distribution of cattle.

Yellow colouration of the lower leave of a growing maize plant may be due to deficiency in

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Yellowing of the lower leaves of a growing maize plant may indicate a deficiency in nitrogen. Nitrogen is an essential nutrient for plant growth and helps with the production of chlorophyll, which gives leaves their green color. When a plant lacks nitrogen, it can result in yellowing of the lower leaves first as the plant prioritizes its use of available nitrogen to maintain growth of the upper leaves. To correct the issue, nitrogen fertilizers can be applied to the soil to supply the plant with the necessary nitrogen.

Which of the following statements about agricultural development is true? It leads to I. increased processing of produce II. increased food production III. high productivity IV. increased agricultural labour force

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The correct answer is option A, which is "I, II and III only". Agricultural development is the process of improving and increasing the agricultural production, productivity, and profitability of the agricultural sector. It involves the application of modern technologies, methods, and practices to improve the efficiency of agricultural production. Increased processing of produce (I) is one of the outcomes of agricultural development. This is because the development of the agricultural sector results in increased production, which in turn creates a demand for processing and preservation of agricultural produce. Increased food production (II) is also a key outcome of agricultural development. Through the use of modern farming methods, such as the use of improved seed varieties, irrigation, and mechanization, agricultural production can be significantly increased, leading to a surplus of food. High productivity (III) is another outcome of agricultural development. When modern farming practices and technologies are used, the efficiency of the agricultural sector is improved, leading to increased yields and reduced wastage. However, agricultural development does not necessarily lead to an increased agricultural labour force (IV). In fact, with the adoption of modern technologies and practices, it is possible to reduce the amount of labor required for agricultural production while increasing productivity. Therefore, option D is incorrect. In summary, the correct answer is option A, which includes increased processing of produce, increased food production, and high productivity as the true statements about agricultural development.

In which layer of the soil profile does most biological activity occur?

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Most biological activity occurs in the A-horizon of the soil profile. The A-horizon, also known as the topsoil, is the uppermost layer of the soil profile and is typically rich in organic matter, minerals, and microorganisms. This layer is where most plant roots are located, and it is where many soil-dwelling organisms, such as bacteria, fungi, and earthworms, live and carry out essential processes such as nutrient cycling and decomposition. The high concentration of organic matter in the A-horizon is due to the accumulation of dead plant material and other organic debris. This organic matter serves as a food source for the soil-dwelling organisms, which in turn help to break down the organic matter and release nutrients into the soil. The nutrients released from the organic matter are then available for uptake by plant roots. In summary, the A-horizon is the layer of the soil profile where most biological activity occurs. It is rich in organic matter and is home to many microorganisms that carry out important functions such as nutrient cycling and decomposition. This layer is vital for supporting plant growth and maintaining healthy soils.

In crop production, ginger is propagated by

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Ginger is propagated by using its rhizomes. Rhizomes are underground stems that grow horizontally and have nodes from which new roots and shoots develop. Ginger is a tropical plant that grows up to about 3 feet tall and produces a thick, knotty, and aromatic rhizome. This rhizome can be broken into smaller pieces, each with at least one bud, and then planted into soil. The buds on the rhizomes will grow into new shoots, and the roots will grow down into the soil. As the plant grows, it will produce more rhizomes, which can be harvested and used for cooking, medicinal purposes, or for replanting. This process of breaking up and planting rhizomes is known as vegetative propagation. While ginger can produce seeds, it is not commonly propagated this way as the seeds are sterile and do not produce viable offspring. Additionally, while bulbs and corms are also used for propagation in other plant species, they are not commonly used for ginger.

The correct sequence of feed utilization in farm animals is

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In animal production, newly-born rabbits are called

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Newly-born rabbits are commonly called "kits" or "bunnies."

The process of grafting in crop production involves

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Grafting is a process in crop production that involves the joining of two different parts of related crops. Specifically, it involves taking a bud, shoot or branch from one plant (the scion) and attaching it to the stem or root system of another plant (the rootstock). The two parts are then secured together until they heal and grow into a single plant. Grafting is a common technique used in horticulture to create new and improved plant varieties. It is particularly useful for crops that are difficult to propagate through traditional means like cuttings or seeds, or for those that have desirable traits in one part of the plant but not in another. By grafting the desired scion onto a strong rootstock, the plant can inherit the best traits of both parts and produce higher yields, better quality fruit, and greater resistance to pests and disease.

The following are advantages of sub-surface irrigation except that

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The disadvantage of sub-surface irrigation is that it can be used only for specific types of crops. Sub-surface irrigation involves placing irrigation pipes or tubing below the soil surface, which delivers water directly to the root zone of the plants. This method of irrigation is particularly useful for soils with low water holding capacity because it reduces the rate of evaporation and ensures that the water is delivered directly to the roots where it is needed most. Additionally, sub-surface irrigation can help reduce the incidence of pests by keeping the foliage dry and reducing the amount of water that is available for pests to thrive. However, the disadvantage of sub-surface irrigation is that it can only be used for specific types of crops. This is because some crops, such as those with shallow root systems or those that are planted in high-density arrangements, may not be able to access the water that is delivered through sub-surface irrigation. As a result, it is important to carefully consider the crop and soil type when choosing an irrigation method.

Soil water that is available for root absorption at field capacity is

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The soil water that is available for root absorption at field capacity is called capillary water. Capillary water is the water that remains in the soil after the gravitational water has drained away. It is held in the small spaces between soil particles by capillary forces, which are the same forces that cause water to rise in a narrow tube. Capillary water is important for plant growth because it is held tightly to the soil particles, but is still available for plant roots to absorb. Hygroscopic water, on the other hand, is held too tightly to the soil particles for plant roots to absorb, while gravitational water drains away too quickly for roots to access. Superfluous water is water that is not absorbed by the soil and drains away due to excess water in the soil. So, in summary, capillary water is the water that is available for plant roots to absorb at field capacity, and it is held in the soil by capillary forces.

In preparing for parturition of a sow,warmth should be provided to

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In preparing for the birth of a sow, warmth should be provided to prevent chilling of the young. This is important because newborn piglets are unable to regulate their body temperature effectively, so if they get too cold, it can negatively impact their health and survival. By providing warmth, the sow and her piglets will be more comfortable, and the young piglets will be able to grow and develop properly.

Piglet anaemia can be controlled by using

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Piglet anemia can be controlled by using iron drugs. Anemia is a condition where the body does not have enough healthy red blood cells to carry sufficient oxygen to the body's tissues. Iron is an essential component of hemoglobin, the protein in red blood cells that carries oxygen from the lungs to the rest of the body. By supplementing the piglets with iron, the red blood cell production can be increased, helping to overcome anemia. Antibiotics may also be used in some cases if there is an underlying bacterial infection causing the anemia. Anthelmintics may also be used if the anemia is caused by a parasite infestation. However, sulphur drugs are not typically used to treat piglet anemia.

Which of the following insects transmits swollen shoot disease of cocoa?

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The insect that transmits swollen shoot disease of cocoa is the mealybug. Mealybugs are small, sap-sucking insects that feed on the sap of the cocoa plant, causing it to become stunted and distorted. They also produce a sticky, sugary substance known as honeydew, which can attract other pests and provide a breeding ground for mold. The honeydew and mold can also lead to a secondary infection of the cocoa plant, which can further weaken and damage it. In conclusion, mealybugs can cause serious harm to cocoa plants, and their feeding and honeydew production can lead to the transmission of the swollen shoot disease, making them the primary insect responsible for this problem.

Which of the following statements is correct about micro-nutrients? They

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The correct statement about micro-nutrients is that they are required by plants in very small quantities. Micro-nutrients, also known as trace elements, are essential nutrients required by plants in small quantities for their growth and development. Unlike macro-nutrients such as nitrogen, phosphorus, and potassium, which are required in large amounts, micro-nutrients are needed in very small quantities. Micro-nutrients play important roles in various metabolic processes such as photosynthesis, respiration, and hormone synthesis. They are also important for the formation of enzymes and other proteins that are necessary for plant growth and development. Some examples of micro-nutrients include iron, zinc, copper, manganese, boron, molybdenum, and chlorine. Deficiency of these nutrients can result in stunted growth, poor yields, and reduced plant quality.

The main objectives of establishing forest in the arid regions is to

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The main objective of establishing forests in arid regions is to "check desert encroachment." Arid regions are characterized by low rainfall, high temperatures, and limited vegetation cover. As a result, they are prone to desertification, which is the gradual process of turning productive land into desert. Desertification can be caused by human activities such as overgrazing, deforestation, and improper land use practices, as well as natural factors such as climate change and drought. Establishing forests in arid regions can help to check desert encroachment by increasing the vegetative cover and protecting the soil from erosion. Forests also help to stabilize the climate by reducing the amount of carbon dioxide in the atmosphere through photosynthesis. Additionally, they help to maintain the water cycle by increasing the amount of rainfall and reducing the amount of runoff. While providing firewood for cooking, bushmeat, and improving the beauty of the environment may be important co-benefits of establishing forests in arid regions, the primary objective is to prevent desertification and preserve the productivity of the land.

Which of the following properties of soil determines its water-holding capacity? I. Texture II. pH III. Colour IV. Structure

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The properties of soil that determine its water-holding capacity are texture and structure. Soil texture refers to the relative amounts of sand, silt, and clay in the soil. Soils with more clay have a greater water-holding capacity than soils with more sand. This is because clay particles are smaller and have a larger surface area than sand particles, allowing them to hold more water. Soil structure refers to the way that soil particles are arranged and held together. Soils with good structure, such as those with a lot of organic matter, tend to have more pore spaces that can hold water. On the other hand, soils with poor structure, such as those that have been compacted or that lack organic matter, tend to have fewer pore spaces and therefore a lower water-holding capacity. Soil pH and colour do not directly affect a soil's water-holding capacity, although they can indirectly influence it by affecting the health and activity of soil organisms that contribute to soil structure and organic matter content.