WAEC SSCE - Agricultural Science - 2021

Maelezo ya Majibu

Maelezo ya Majibu

Inspecting yam stored in a barn at least once a week helps to prevent mouldiness, remove sprouts and rotten tubers. During storage, yams may sprout or start to rot due to changes in temperature, humidity or mechanical damage. Regular inspection helps to identify and remove these sprouts and rotten tubers before they spread and cause spoilage to other yams. Inspections can also help to identify and control any pest attacks that may occur, preventing further damage to the yams.

Maelezo ya Majibu

Maelezo ya Majibu

Maelezo ya Majibu

A farmer practices crop rotation in order to improve soil fertility. Crop rotation is a farming practice where different crops are grown in a specific sequence or rotation on the same piece of land over multiple seasons. The main purpose of crop rotation is to maintain and enhance the health of the soil. When the same crop is grown continuously in the same field, it depletes the soil of specific nutrients that are essential for that particular crop. This can lead to reduced yield and nutrient imbalances in the soil. Additionally, continuous cropping of a single crop can also increase the risk of pests and diseases that specifically target that crop. By practicing crop rotation, farmers alternate the types of crops grown in a particular field. Different crops have different nutrient requirements, root systems, and interaction with pests and diseases. This helps to break the pest and disease cycles, prevent the buildup of pests and diseases specific to a particular crop, and reduce the dependence on chemical pesticides. Furthermore, different crops have different root systems that vary in their depth and structure. This can help improve soil structure and prevent soil erosion. Some crops have deep roots that can break up compacted soil, while others have fibrous roots that add organic matter and improve soil texture. In summary, crop rotation helps to improve soil fertility by diversifying the nutrient demands, disrupting pest and disease cycles, and promoting healthier soil structure. It is an effective way for farmers to maintain and enhance the productivity and sustainability of their farmland over the long term.

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Microorganisms that decompose organic matter will function best under an optimum soil pH. This is because most microorganisms that break down organic matter work best in a neutral to slightly acidic pH range of 6.0 to 7.5. Outside of this range, their activity can be reduced, which slows down the decomposition process. Therefore, it is important to maintain a balanced pH level in the soil to promote the growth and activity of microorganisms that help to decompose organic matter.

Maelezo ya Majibu

Maelezo ya Majibu

Maelezo ya Majibu

Feeds that have more than 18% fibre are classified as roughages. Roughages are feeds that contain a high percentage of fibre and are commonly low in digestible nutrients. They are typically used to supplement the diets of livestock and provide them with the necessary fibre to aid digestion and maintain a healthy digestive system. Examples of roughages include hay, straw, silage, and pasture grasses.

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To determine the percentage of organic matter in the soil, we need to calculate the weight of the organic matter that was lost during the burning process. The weight of the organic matter can be calculated as follows: Weight of over-dried soil before burning - Weight of over-dried soil after burning = Weight of organic matter Substituting the given values, we get: 50g - 28g = 22g Therefore, the weight of organic matter is 22g. To calculate the percentage of organic matter, we need to divide the weight of organic matter by the weight of over-dried soil before burning and multiply by 100. (22g / 50g) x 100 = 44% Therefore, the percentage of organic matter in the soil is 44%. So the correct option is "44%".

Maelezo ya Majibu

Maelezo ya Majibu

The branch of crop science which deals with the study of insect pests is entomology. Entomology is the study of insects and their relationship with plants and other organisms. It involves the study of insect anatomy, behavior, ecology, and control measures. In crop science, entomology is an important field because insect pests can cause significant damage to crops and reduce crop yields. Therefore, entomologists work to identify and develop control measures to manage insect pests in crop production.

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Trypanosomiasis is a disease that affects cattle, among other animals. N'dama and Muturu are breeds of cattle that are well known for their resistance to trypanosomiasis. Therefore, the answer is "N'dama and Muturu."

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Elaeis guineensis and Arachis hypogaea are examples of oil crops. Oil crops are plants that are primarily cultivated for their oil-rich seeds or fruits. Elaeis guineensis, also known as the oil palm, produces palm oil from its fruit. Arachis hypogaea, commonly known as groundnut or peanut, produces oil from its seeds. These crops are specifically grown for their oil content, which is extracted and used for various purposes such as cooking, food processing, and manufacturing of cosmetic and industrial products.

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Adoption of research findings by farmers can help to solve the problem of poor agricultural practices which lead to reduced productivity and yield. By adopting new research-based practices and technologies, farmers can improve their yields, reduce crop losses, and increase their income. Therefore, the option that best fits the question is "poor extension services" since research findings can help provide better extension services to farmers, which in turn can lead to improved farming practices and better yields.

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Maelezo ya Majibu

To calculate the expected plant population of Okro seeds sown on 0.72 hectares of farmland at a spacing of 60cm, we need to know the area of the land in square meters. 1 hectare is equal to 10,000 square meters, so 0.72 hectares is equal to 7,200 square meters (0.72 x 10,000 = 7,200). To calculate the expected plant population, we need to divide the area of land by the square of the spacing between plants. In this case, the spacing is given as 60cm, which is equal to 0.6 meters. So, the expected plant population is: 7,200 / (0.6 x 0.6) = 20,000 Therefore, the expected plant population for Okro seeds sown on 0.72 hectares of farmland at a spacing of 60cm is 20,000 plants.

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Maelezo ya Majibu

The causative organism of maize rust is a fungus. Maize rust is a plant disease that affects corn, or maize, plants. It is caused by a specific type of fungus known as Puccinia polysora. This fungus belongs to the group of organisms known as fungi. Fungi are organisms that can be found in various environments, including soil, plants, and even in the air. They are distinct from other types of organisms, such as bacteria, protozoa, and viruses. In the case of maize rust, the fungus Puccinia polysora infects the maize plant, causing characteristic symptoms such as reddish-brown or orange-colored pustules or lesions on the leaves, stalks, and ears of the plant. These pustules contain fungal spores that are spread through wind, rain, or physical contact. Fungi, including Puccinia polysora, are known to be important plant pathogens, causing diseases in various crops and plants. They rely on the plant's nutrients and tissues to grow and reproduce, leading to damage and reduced crop yield. Understanding the causative organism of a plant disease like maize rust is crucial for effective management and control strategies. By identifying the fungus as the causative agent, farmers and agricultural professionals can implement appropriate measures such as crop rotation, fungicide applications, and resistant crop varieties to minimize the impact of the disease and protect maize crops. Therefore, in the case of maize rust, the causative organism is a fungus, specifically the Puccinia polysora fungus.

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The construction of rural feeder roads in agriculture helps to improve access to various services such as marketing, transportation, and extension services, which can boost productivity and profitability. It can also help reduce the cost of transportation of farm inputs and outputs. However, rural feeder roads construction may not directly address land tenure issues which may affect the ability of farmers to access and use land for agricultural purposes. Therefore, the correct answer is "land tenure system."

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Maelezo ya Majibu

The propagation of ginger is generally done using its rhizome. Rhizomes are modified stems that grow underground and are used for vegetative propagation of ginger. They are cut into small pieces with at least one bud and planted in soil for growth. This method of propagation ensures that the genetic characteristics of the parent plant are retained in the offspring, thereby ensuring desirable traits like disease resistance, yield, and quality.

Maelezo ya Majibu

Maelezo ya Majibu

Maelezo ya Majibu

Horse racing and polo are events where horses are used for recreation. Horse racing is a sport where horses race against each other to determine which is the fastest, while polo is a team sport played on horseback, where players use mallets to hit a ball into the opposing team's goal. Both events are primarily for entertainment and recreational purposes, rather than transportation or dowry payment.

Maelezo ya Majibu

Maelezo ya Majibu

Formation of blisters on the mouth and the skin around the hoof of farm animals is a symptom of Foot and Mouth Disease. Foot and Mouth Disease is a viral disease that affects cloven-hoofed animals such as cattle, sheep, goats, and pigs. The disease causes the formation of blisters on the mouth, tongue, nose, and around the hoof of infected animals. The blisters eventually burst, leaving painful sores that can make it difficult for the animal to eat, walk, and stand. The disease is highly contagious and can spread rapidly between animals, which can lead to significant economic losses in the livestock industry.

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Maelezo ya Majibu

Maelezo ya Majibu

Maelezo ya Majibu

Maelezo ya Majibu

The structure that should be located on high elevation in planning a farmstead is the farmhouse. This is because the farmhouse is the most important structure on the farmstead, as it serves as the residence of the farmer and his family. Placing the farmhouse on high elevation will provide a better view of the farm and surrounding areas, which will aid in the management of the farm. Additionally, it will protect the farmhouse from flooding during the rainy season. The other structures such as fish pond, pigsty, and processing shed can be located on lower elevations as they do not require the same level of prominence and protection as the farmhouse.

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The practice that will improve clay soil is the addition of organic material. Organic material such as compost, manure, and plant residues can improve soil structure, increase soil aeration, and enhance water retention capacity. This is because organic matter helps to bind soil particles together, creating a more stable soil structure that is less prone to compaction. In contrast, the use of acid-forming fertilizers, bush burning, and addition of sodium chloride can have negative effects on soil health and may lead to soil degradation.

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To determine the cost of feeding the birds for 6 weeks, we first need to find the total amount of feed consumed by the birds in 6 weeks. Total feed consumed by birds in 6 weeks = 0.7 kg/week x 6 weeks = 4.2 kg If 1 kg of feed costs #5, then 4.2 kg will cost: 4.2 kg x #5/kg = #21.00 Therefore, the cost of feeding the birds for 6 weeks is #21.00. So, the answer is option C, #21.00.

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Maelezo ya Majibu

Maelezo ya Majibu

The botanical name for onion is Allium cepa. Botanical names are a standardized way of identifying plants, and they consist of two parts: the genus and the species. In this case, the genus is Allium, which includes various plants such as garlic and chives, and the species is cepa, which specifically identifies the onion plant.

Maelezo ya Majibu

Maelezo ya Majibu

Maelezo ya Majibu

A plot of land devoted to the cultivation of fruit trees is called an orchard. An orchard is a specialized type of farm that is dedicated to growing and harvesting fruit trees, such as apple, pear, peach, or citrus trees. The term "orchard" can also refer to the collection of trees themselves, which are often arranged in rows or blocks to facilitate care and harvesting. The purpose of an orchard is to produce a high yield of quality fruit that can be sold to consumers or used for processing into juices, jams, and other products.

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To calculate the weight of organic matter in the soil, we need to find the weight of the portion of the soil that was burned off during the experiment. We can do this by subtracting the weight of the soil after burning from the weight of the soil before burning: Weight of organic matter = Weight of over-dried soil before burning - Weight of over-dried soil after burning Weight of organic matter = 50g - 28g Weight of organic matter = 22g Therefore, the weight of organic matter in the soil is 22g. The answer is.

Maelezo ya Majibu

Maelezo ya Majibu

The best way for a young animal to obtain colostrum is by allowing it to suckle the dam. Colostrum is the first milk produced by the mother immediately after giving birth. It is rich in essential nutrients, antibodies, and immune factors that are crucial for the health and survival of the newborn animal. By allowing the young animal to suckle the dam, it can directly access and consume the colostrum, receiving its numerous benefits. Powdered milk or warm milk may not provide the same level of essential nutrients and antibodies as colostrum. Injecting the animal with progesterone is unrelated to obtaining colostrum and serves a different purpose. Therefore, allowing the young animal to suckle the dam is the most effective way to ensure it receives the vital colostrum it needs for a healthy start in life.

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The major source of water to the plants in the diagram is capillary water. Capillary water refers to the water that is held in the soil and is available for plant roots to absorb. It is the result of the capillary action, which is the movement of water through tiny spaces or pores in the soil due to the forces of cohesion and adhesion. When it rains or when the soil is irrigated, water infiltrates into the soil and fills the spaces between soil particles. The force of cohesion between water molecules allows it to move upward against gravity, while the force of adhesion between water molecules and the soil particles allows water to stick to the soil surfaces and move laterally. Plant roots have tiny root hairs that extend into the soil, and these root hairs are in close contact with the soil particles. As the water moves upward and laterally through capillary action, it comes into contact with the root hairs, and the roots absorb the water through osmosis. This capillary water provides plants with the necessary moisture and nutrients for their growth and survival. While other sources of water like gravitational water (water that drains through the soil due to gravity), hygroscopic water (water that is tightly bound to the soil particles and is not available to plants), and surface water (water on the surface of the soil) also contribute to the overall water availability, capillary water is the primary source that directly nourishes the plants. In conclusion, capillary water, which is held in the soil and moves through capillary action, is the major source of water that plants in the diagram can access and absorb through their roots.

Maelezo ya Majibu

Maelezo ya Majibu

An advantage of zero-grazing is that it prevents depletion of pasture. Zero-grazing is a system of livestock management where animals are confined in a housing unit, rather than being allowed to graze freely. Since the animals are not grazing in a pasture, there is no depletion of pasture, which means that the farmer does not have to spend money on pasture management. Additionally, zero-grazing can help to increase the productivity of the animals since they are kept in a controlled environment with adequate feed and water. It is also easier to monitor and manage the animals in a zero-grazing system compared to a free-range system, which can help to prevent diseases and increase the efficiency of livestock production.

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Maelezo ya Majibu

The two species of kola grown for commercial purposes in West Africa are Cola nitida and Cola acuminata. Cola nitida, also known as the bitter kola, is a species of kola tree that is widely cultivated in West Africa. It produces bitter nuts that are commonly consumed for their medicinal properties and are also used as a flavoring agent in certain beverages and confectionery products. Cola acuminata, also known as the kola nut or the cola tree, is another species of kola tree grown in West Africa. Its nuts are larger and have a milder flavor compared to Cola nitida. They are often used in the production of soft drinks, particularly cola beverages, due to their natural caffeine content and characteristic taste. Both Cola nitida and Cola acuminata have economic importance in the region, as they are valuable crops for trade and local consumption. They are recognized for their cultural and traditional significance, as well as their various uses in traditional medicine and as stimulants.

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The pair of raw materials used in the canning industry is meat and fish. The canning industry involves the preservation of food items in sealed cans or containers to extend their shelf life and maintain their quality. Meat and fish are commonly processed and canned to provide convenient and long-lasting food products. Meat, such as beef, pork, and poultry, is a valuable source of protein for many people. Canning allows meat to be preserved without the need for refrigeration, making it more accessible and transportable. The meat is typically cooked, processed, and sealed in cans along with appropriate preservatives to prevent spoilage. Fish, including various types such as tuna, salmon, and sardines, is also widely canned. Canned fish provides a convenient and nutritious food option, especially for areas where fresh fish may not be readily available. The fish is cleaned, cooked, and canned along with oils, sauces, or brine to enhance flavor and preservation. These raw materials, meat and fish, are carefully selected and processed to meet the quality and safety standards required in the canning industry. The canning process involves sealing the cans to create a sterile environment, ensuring the preservation of the meat and fish for an extended period. In summary, the canning industry utilizes meat and fish as primary raw materials to provide preserved, ready-to-eat food products that are convenient, long-lasting, and widely accessible.

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To calculate the percentage change in quantity supplied, we need to use the following formula: Percentage Change = ((New Value - Old Value) / Old Value) x 100% In this case, the old value is the quantity supplied at a price of 24 (#), which is 480 (kg), and the new value is the quantity supplied at a price of 16 (#), which is 400 (kg). So, using the formula, we get: Percentage Change = ((400 - 480) / 480) x 100% Percentage Change = (-80 / 480) x 100% Percentage Change = -16.67% Therefore, the percentage change in quantity supplied for maize is 16.67% (rounded to one decimal place).

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(a) Identification of specimens:

J= Leaf eating beetle

K = Aphid

L = Bean beetle

 M = Termites or Mole Cricket.

(b) Damage done to crops by specimens K and L are: Specimen K (Aphid) 

(i) It causes stunted growth 

(ii) It causes galls on leaves. 

(iii) It is a vector of diseases. Specimen L (Callosobruchus spp) 

(i) They bore holes into grains and eat them up. 

(ii) They reduce the quality of stored produce. 

(iii) They reduce grains to powder.

(c)

(i) Spray with insecticides. 

(ii) Hand pick them. 

(iii) Use resistant varieties. 

(iv) Early planting 

(v) Crop rotation.

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(a) specimens

N = Fresh skin of poultry fowl

O = Fresh skin /hide of ruminant

P = Kidney (whole) of goat

Q = Horn

(b) Specimen N is derived from poultry birds such as domestic fowl, turkey, goose, duck etc while specimen O is derived from ruminant animals like cattle, sheep, and goat.

(c) Two functions of specimens N, O, and P that are common to farm animals are

N

(i) It protects the internal organs. 

(ii) It prevents the entrance of disease organisms.

O

(i) It aids excretion. 

(ii) It aids the production of milk in females.

P 

(i) It aids excretion

 (ii) It helps in the osmo- regulation of the body.

(d)

(i) It can be used to make shoe, belt, cap, baskets, drum, etc.

 (ii) Tick, Liver fluke, Tapeworm, or Ascaris.

(e) The condition in which an animal does not possess specimen Q is when the animal is a non-ruminant.

(f) Importance of specimen Q to farm animals are 

(i) It is used to fight or defend themselves. 

(ii) It gives them shape 

(iii) It aids swimming, e.g. kuri cattle.

Importance of specimen Q to man are 

(i) It serves as raw material in knife handles, belt heads etc. 

(ii) It is used for decorative purposes. 

(iii) It is used to make livestock feeds

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(a) ldentification of specimens:

D = Measuring tape, E = 

Budding knife

F = Plier

G = Measuring chain or Gunter's chain

H = Spanner

I = Screwdriver

(b) Functions of each of the specimens are:

D is used in taking measurements of length, breadth, and height.

E is used mainly in budding (by vegetative propagation) in citrus, cocoa, rubber etc.

F is used:

(i) For gripping firmly and twisting wires

(ii) for holding bolts and nuts.

G is used in taking a short or detailed measurements of length and breadth.

H is used in loosening or tightening of nuts/ bolts on farm machines.

I is used for turning or screwing nails or Screws into or out of wooden or metal surfaces and to detect the presence of electric current.

(c) Methods of maintaining each of the specimens are 

D = Clean after use

E = Sharpen cutting edge regularly

 F = Oil or grease after use

G = Store in a cool and dry place

H = Oil or grease metal parts before storage

 I = use according to specification or for the intended purpose.

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a. (i) Some of the main agricultural extension methods that could be used to create awareness of diseases among poultry farmers are:

• Workshops and seminars: Organizing workshops and seminars where poultry farmers can learn about the disease and how to prevent it.
• Field days: Organizing field days where farmers can observe how to identify and treat the disease.
• Printed materials: Distributing printed materials such as flyers, brochures, and posters that provide information about the disease and how to prevent it.
• Audiovisual materials: Creating audiovisual materials such as videos and slideshows that can be shown to farmers to educate them about the disease.

(ii) The most appropriate extension method to create awareness of the disease among poultry farmers would be workshops and seminars. This is because workshops and seminars provide a platform where farmers can interact with experts and other farmers to learn about the disease and how to prevent it. This method allows for interactive learning, which is more effective in creating awareness and ensuring that farmers understand the disease and its prevention.

(iii) The reason for choosing the mass method is that it allows for the dissemination of information to a large number of people at once. This is important when dealing with a disease outbreak, as it allows for quick dissemination of information to farmers, which can help prevent the spread of the disease.

(iv) Some problems likely to be encountered by the use of the mass method include the possibility of information overload, where farmers may not be able to absorb all the information provided to them. Additionally, the method may not be effective in reaching all farmers, especially those in remote areas with limited access to information and communication technologies.

b. Some problems faced by farm managers include:

• Managing production costs: Farm managers need to manage production costs to ensure profitability. This involves managing input costs such as feed, labor, and equipment, and ensuring that they do not exceed the revenue generated from sales.
• Marketing: Farm managers need to ensure that their products are marketed effectively to generate sales. This involves identifying market opportunities, developing marketing strategies, and building relationships with buyers.
• Managing risks: Farm managers need to manage risks such as disease outbreaks, weather events, and market fluctuations. This involves implementing risk management strategies such as insurance, diversification, and contingency planning.
• Managing labor: Farm managers need to manage labor effectively to ensure that the farm operates efficiently. This involves recruiting, training, and retaining skilled labor, as well as managing labor costs.

c. Some common breeds of goats found in West Africa include the West African Dwarf, the Sahelian, and the Red Sokoto. The West African Dwarf is a small, hardy breed that is well adapted to the humid conditions of West Africa. The Sahelian is a larger breed that is well adapted to the arid conditions of the Sahel region. The Red Sokoto is a meat breed that is well adapted to the semi-arid conditions of northern Nigeria. These breeds are well adapted to the environmental conditions and farming systems in West Africa and are commonly kept by smallholder farmers for meat and milk production.

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a. Reasons why farm operations are important: (i) Pruning of cocoa trees: 1. Enhanced tree health: Pruning helps remove dead, diseased, or damaged branches, promoting overall tree health. It allows better air circulation and sunlight penetration, reducing the risk of fungal infections and pests. 2. Increased yield: Pruning encourages new growth and stimulates the development of fruit-bearing branches, leading to higher cocoa bean production. 3. Easy harvest: Properly pruned cocoa trees have a well-defined canopy, making it easier for farmers to access and harvest the cocoa pods. 4. Disease control: Pruning facilitates disease control measures as it allows farmers to spot and remove infected branches promptly, preventing the spread of diseases within the cocoa plantation. (ii) Parboiling of paddy rice: 1. Improved grain quality: Parboiling involves partially boiling the rice in its husk before milling. This process enhances the nutritional value and taste of the rice while retaining essential vitamins and minerals. 2. Reduced processing time: Parboiling softens the rice kernels, making it easier to remove the husk during milling. This reduces the time and effort required for processing, resulting in increased efficiency. 3. Enhanced storage and shelf life: Parboiling reduces the moisture content of rice and improves its resistance to pests and insects. It also prevents the development of mold, extending the shelf life of the rice. 4. Enhanced cooking properties: Parboiled rice retains its shape, texture, and flavor better during cooking, resulting in fluffy, separate grains. It is less prone to overcooking or becoming sticky, making it more desirable for consumers. b. Ways of eradicating guinea grass in a farmland: 1. Manual removal: Physically uprooting or cutting the guinea grass is an effective way to control its growth. Ensure that the roots are completely removed to prevent regrowth. 2. Herbicides: Applying herbicides specifically designed to target grassy weeds like guinea grass can be an efficient method. Follow the instructions and safety guidelines provided by the herbicide manufacturer. 3. Mulching: Applying a thick layer of organic mulch around desired plants can suppress the growth of guinea grass by blocking sunlight and impeding its germination. 4. Regular mowing: Keeping the grass at a low height through regular mowing can weaken and suppress the guinea grass. This method should be combined with other control measures for better effectiveness. 5. Prevention: Maintaining good farm hygiene by regularly removing weeds, especially before they produce seeds, can prevent the spread and establishment of guinea grass. c. Uses of ornamental plants: 1. Aesthetics: Ornamental plants are primarily grown for their beauty and visual appeal. They enhance the overall aesthetics of gardens, parks, and landscapes, providing a pleasant and inviting environment. 2. Stress reduction: Being surrounded by greenery and nature has been found to reduce stress and improve mental well-being. Ornamental plants contribute to creating a calming and relaxing atmosphere. 3. Environmental benefits: Ornamental plants play a role in improving air quality by absorbing carbon dioxide and releasing oxygen during photosynthesis. They also help mitigate noise pollution and provide habitat for wildlife. 4. Educational purposes: Ornamental plants provide educational opportunities, especially for children, to learn about plant biology, gardening, and environmental conservation. 5. Cultural significance: Many ornamental plants hold cultural or symbolic value in various societies and traditions. They can be used in religious ceremonies, festivals, and decorations during special occasions. 6. Wildlife attraction: Certain ornamental plants attract birds, butterflies, and other pollinators, contributing to biodiversity and ecosystem health. 7. Economic value: Ornamental plants form the basis of the horticulture industry, including nurseries, florists, and landscaping businesses. They contribute to

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a) The roles played by the following factors in soil formation are:

(i) Time: Time is an essential factor in soil formation, as it allows for the gradual accumulation of organic matter, weathering of rocks, and the development of soil structure. Over time, soil also becomes more diverse in terms of its physical, chemical, and biological properties, leading to the formation of different soil types.

(ii) Rainfall: Rainfall is another critical factor in soil formation, as it influences soil structure, nutrient availability, and the transport of minerals and organic matter. In areas with high rainfall, leaching can occur, leading to the depletion of essential nutrients. In contrast, low rainfall can result in soil salinization and compaction.

(iii) Parent Material: Parent material refers to the underlying rock or sediment from which the soil is formed. Different types of parent material have varying mineral compositions, which affect the fertility and physical properties of the soil. For example, soils formed from limestone are generally alkaline, while those formed from granite tend to be more acidic.

b) Principles that should be followed in a good crop rotation plan include:

(i) Diversity: A good crop rotation plan should include a diverse range of crops to reduce the risk of disease and pest outbreaks and maintain soil fertility.

(ii) Timing: The timing of crop rotations is also crucial, as different crops have varying nutrient requirements and growth rates. A well-planned crop rotation should consider the optimal timing for planting, harvesting, and fallowing.

(iii) Soil health: A good crop rotation plan should aim to improve soil health by reducing erosion, maintaining soil structure, and increasing soil organic matter.

c) Forage crops are plants that are grown specifically for livestock feed. The uses of forage crops include:

(i) Providing nutrition: Forage crops are a source of high-quality feed for livestock, providing essential nutrients such as protein, fiber, and energy.

(ii) Improving soil health: Forage crops can improve soil health by adding organic matter, reducing soil erosion, and enhancing soil structure.

(iii) Cost-effective: Forage crops can be a cost-effective alternative to purchased feeds, reducing the overall cost of livestock production.

(iv) Sustainability: Forage crops are an essential component of sustainable agriculture, as they can help to reduce the environmental impact of livestock production by reducing the need for synthetic fertilizers and other inputs.

Maelezo ya Majibu

a. The roles of the government of West African countries in agricultural development are as follows: (i) Agricultural finance: The government plays a crucial role in providing financial support to the agricultural sector. This includes offering loans, grants, and subsidies to farmers, especially small-scale farmers who may have limited access to capital. The government may also establish agricultural development banks or funds to provide financial assistance and promote investment in agriculture. (ii) Agricultural education: The government recognizes the importance of educating farmers and individuals involved in the agricultural sector. They establish agricultural colleges, universities, and training centers to provide formal education and training in agricultural practices, techniques, and technologies. These institutions offer courses on crop cultivation, animal husbandry, agricultural economics, and other relevant subjects. (iii) Agricultural extension services: Governments set up agricultural extension services to bridge the gap between agricultural research and farmers. These services aim to disseminate up-to-date information, best practices, and new technologies to farmers. Extension workers, often employed by the government, visit rural areas to provide guidance, advice, and training to farmers, helping them improve their farming methods and productivity. (iv) Agricultural policies and programs: Governments formulate agricultural policies and programs to provide a framework for sustainable agricultural development. These policies encompass areas such as land reform, crop diversification, irrigation, rural infrastructure development, market access, and trade regulations. The government's role is to design and implement these policies, ensuring they align with the needs and priorities of the agricultural sector and contribute to its growth and productivity. b. Structural differences between disc plough and disc harrow: Disc Plough: - The disc plough is a tillage implement used for primary or deep ploughing. - It has large, concave metal discs (usually two or more) mounted on a frame. - The discs are spaced apart and have a cutting edge that penetrates the soil and turns it over. - The plough is pulled by a tractor, and the discs create furrows in the soil as they rotate. - It is primarily used for breaking up hard or compacted soil, burying crop residues, and preparing the land for planting. Disc Harrow: - The disc harrow is a secondary tillage implement used after ploughing to prepare the soil for planting. - It consists of a series of smaller, individual concave metal discs mounted on a common shaft. - The discs are closely spaced and have a serrated edge that cuts through the soil and breaks up clumps. - The harrow is also pulled by a tractor, and the discs rotate as they move along the ground. - It is primarily used for leveling the soil, breaking up clods, and incorporating fertilizers or amendments into the topsoil. c. Effects of frequent use of disc plough on the soil: Frequent use of a disc plough can have both positive and negative effects on the soil. Here are some simple explanations: Positive effects: 1. Soil loosening: The disc plough breaks up compacted soil and loosens it, which improves aeration and water infiltration. This allows plant roots to penetrate the soil more easily and access nutrients. Negative effects: 1. Soil erosion: Intensive or improper use of the disc plough can lead to soil erosion. When the soil is turned over, it becomes more vulnerable to wind and water erosion, potentially causing valuable topsoil to be washed or blown away. 2. Organic matter loss: Disc ploughing can accelerate the decomposition of organic matter present in the topsoil. This may lead to a decrease in soil fertility and a reduction in the soil's ability to retain moisture. 3. Soil compaction: If the disc plough is used when the soil is too wet or not properly managed, it can cause compaction. The weight and repeated passes of

Maelezo ya Majibu

a.

i. Selective exploitation in forest management refers to the practice of harvesting only a portion of the mature trees in a forest, while leaving the rest to continue growing and contributing to the ecosystem. This approach aims to maintain the overall health and productivity of the forest while also providing economic benefits through timber harvesting.

ii. Some advantages of selective exploitation of forest trees include:

• Sustainable management: Selective exploitation helps to ensure that forests are managed in a sustainable manner, as only a portion of the mature trees are harvested, leaving the rest to continue growing and contributing to the ecosystem.
• Biodiversity conservation: Selective exploitation can help to conserve biodiversity by leaving habitat for wildlife and preserving a variety of tree species and other plants in the forest.
• Economic benefits: Selective exploitation provides economic benefits through timber harvesting, while also maintaining the overall health and productivity of the forest.
• Carbon sequestration: Forests play an important role in carbon sequestration, and selective exploitation can help to maintain this function by preserving mature trees that continue to store carbon.

b. Field pests are insects and other organisms that attack crops while they are growing in the field. Examples of field pests include aphids, caterpillars, and grasshoppers. Storage pests, on the other hand, are insects and other organisms that attack crops after they have been harvested and stored. Examples of storage pests include weevils, moths, and beetles.

c.

i. Examples of storage insect pests of crops include the maize weevil, rice weevil, and bean beetle. These insects can infest stored crops such as grains, beans, and nuts, causing damage and reducing the quality of the harvested crops.

ii. Examples of field insect pests of crops include aphids, which can infest and damage a variety of crops including fruits, vegetables, and grains; armyworms, which can cause extensive damage to corn and other crops; and Colorado potato beetles, which can damage potato plants.

d. Ways of conserving water in the soil include:

• Mulching: Mulching involves covering the soil with a layer of organic material such as leaves, straw, or wood chips. This helps to reduce water evaporation from the soil, keeping it moist for longer periods of time.
• Irrigation management: Proper irrigation management can help to conserve water in the soil by reducing water loss through runoff or deep percolation. This can be achieved through techniques such as drip irrigation, which delivers water directly to the roots of plants, or by using water-efficient irrigation systems.
• Soil management: Managing the soil can also help to conserve water. Techniques such as adding organic matter to the soil can improve its water-holding capacity, while reducing tillage can help to minimize soil disturbance and water loss through evaporation.
• Crop selection: Choosing crops that are adapted to the local climate and soil conditions can help to conserve water, as these crops will require less irrigation and can better tolerate dry conditions.

Maelezo ya Majibu

(a) ldentification of specimens:

A = NPK fertilizer 

B = Ammonium Sulphate

C = Lime 

(b) The main nutrient(s) released by each specimen are 

Specimen A = Nitrogen, phosphorus, and potassium; 

Specimen B = Nitrogen

Specimen C = Calcium.

(c) Ammonium Nitrate and urea can be used as substitutes for specimen B.

(d) It can increase the acidity of the soil

(e)

(i) Role of specimen C in crop production are: 

(1) It helps to reduce soil acidity. 

(2) It Increases the activities of soil living organisms. 

(3) It improves the soil structure. 

(4) It increases water percolation in soils. 

(ii) Role of Specimen C in fish production are: 

(1) It serves as an additional source of calcium for bone development in fish. 

(2) It reduces turbidity in the fish ponds through flocculation.

(f)

(i)Quicklime 

(ii) Slaked lime 

(iii) Basic Slag. 

(iv) Dolomite 

(v) Calcium carbonate.