WAEC SSCE - Agricultural Science - 2000

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The hopper of a grain sheller is a part of the machine that receives maize cobs to be shelled. It is usually located at the top of the sheller and serves as a funnel-like structure that channels the cobs into the shelling unit. The hopper is designed to accommodate different sizes of maize cobs and prevent them from bouncing out during the shelling process. Therefore, the correct answer to this question is "receiving maize cobs to be shelled."

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The statement that "they are different from one geographical location to another" is not correct about agricultural regulations within a country. Agricultural regulations within a country are based on the conditions prevailing in that particular country and are aimed at maintaining good quality farm produce as well as increasing agricultural production. However, regulations may differ in different countries based on their specific needs and conditions.

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When sugarcane is allowed to flower before harvesting, the sucrose content is reduced. This is because when the sugarcane plant starts to flower, it begins to divert its energy and resources towards the development of seeds instead of the accumulation of sucrose in the stalks. As a result, the sucrose content of the stalks decreases, and the sugar yield from the crop is reduced. Therefore, sugarcane farmers usually try to prevent flowering and seed formation in the crop by using various cultural practices and chemical treatments to maximize the sucrose content in the harvested crop.

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The primary role of agriculture is the provision of food for man and his animals. Agriculture is the cultivation of crops and the rearing of animals for food, and it is the foundation of food production. Agriculture plays a crucial role in feeding the world's population by producing a variety of crops, such as grains, fruits, vegetables, and livestock, which provide essential nutrients for human survival. Agriculture also provides raw materials for the food processing industries, which produce a variety of food products for consumption. Moreover, agriculture creates employment opportunities and generates income for farmers, contributing to the economic development of rural areas.

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The group of organisms that cause the greatest damage to stored grains are insects. Insects such as weevils, beetles and moths are known to infest stored grains and cause damage by consuming the grains or laying eggs within them, leading to contamination and spoilage. They can also lead to the growth of fungi, which can further damage the grains. Therefore, it is important to properly store and protect grains to prevent insect infestations and subsequent damage.

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The disease that causes abortion in cattle at the later stage of pregnancy is brucellosis.

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Liver fluke is the only hermaphrodite parasite of livestock in the given options. Hermaphrodite refers to an organism that has both male and female reproductive organs. Therefore, the correct answer is liver fluke.

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Granite is not an example of metamorphic rock. Granite is an igneous rock that forms from the cooling and solidification of magma or lava. In contrast, metamorphic rocks are formed from existing rocks that have been altered by heat, pressure, and/or chemical processes. Gneiss, schist, and quartzite are all examples of metamorphic rocks.

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During the process of egg formation, albumen deposition begins in the magnum. The magnum is the second section of the hen's oviduct where the egg white or albumen is secreted. The albumen is produced by the magnum over a period of approximately 3 hours, during which the egg rotates to form its final shape. After the albumen is deposited, the egg then moves into the isthmus section of the oviduct, where the shell membranes are formed around it. Finally, the egg enters the uterus where it is coated with the shell and laid.

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Pennisetum purpureum is the botanical name for Elephant Grass. This is a tall perennial grass species native to Africa that is widely cultivated for forage and pasture purposes. It can grow up to 4 meters tall and has broad leaves that are popular as a feed for cattle, goats, and sheep. It is also used for erosion control, as a biofuel, and for landscaping purposes. The grass is known for its high yield and nutrient content, making it a popular choice among farmers and ranchers.

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Legumes that produce edible seeds are called pulses. Pulses are a type of edible seed that comes from a legume plant such as lentils, chickpeas, beans, and peas. Pulses are high in protein, fiber, and various nutrients, making them a healthy food choice. They are also a staple food in many cultures around the world, and are used in a variety of dishes, including soups, stews, salads, and curries.

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The item that is not considered as capital in agriculture is labor. Capital refers to the various resources that are used in agriculture to produce goods and services. It includes long-term investments such as land, machinery, and livestock. Tree crops, which are a type of long-term investment, can also be considered as capital. Labor, on the other hand, refers to the work or human effort that is involved in the production process, and is considered a variable cost rather than a fixed asset.

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Cotton can thrive well in the mangrove areas if the land is sufficiently drained. Mangrove areas are characterized by their saline and waterlogged soil which makes it difficult for most crops to grow, including cotton. However, cotton can tolerate a certain level of salinity if the soil is well-drained. This allows for proper aeration of the roots and prevents waterlogging which can lead to root rot. Additionally, proper drainage helps to reduce the concentration of salt in the soil, making it more conducive for cotton growth. The other options, such as applying appropriate fertilizer, lower intensity of sunshine, or controlling white flies, do not necessarily address the issue of soil drainage and may not guarantee cotton growth in mangrove areas.

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The most important factor that determines the rate of agricultural development is the adoption of viable agricultural research findings. This means that for agriculture to develop at a significant rate, research must be carried out to find out new ways to improve agricultural practices, and the results of such research must be made available and adopted by farmers. This includes improved crop varieties, better pest and disease management strategies, and new farming techniques that can increase productivity and efficiency. The quantity of herbicides used, number of machinery available, and number of people involved in agriculture can all play a role in agricultural development, but they are not as important as the adoption of viable research findings.

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The secretion of reproductive and growth hormone in animals is controlled by the pituitary gland. The pituitary gland is located at the base of the brain and is often referred to as the "master gland" because it controls the release of hormones from other endocrine glands in the body. It produces and releases several hormones that are important for growth, reproduction, and overall hormonal regulation in animals. The secretion of these hormones is regulated by signals from the brain and feedback mechanisms in the body to ensure proper hormonal balance.

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The correct answer is: demand for rice. The quantity of rice that a consumer is willing and able to buy during a given period is known as the consumer's demand for rice. Demand is a fundamental concept in economics, and it refers to the amount of a product or service that consumers are willing and able to purchase at a given price and within a specific period. It is affected by various factors such as consumer income, the price of the product, the availability of substitute products, and consumer preferences. When the price of rice goes up, the quantity of rice that consumers are willing and able to buy decreases, and when the price goes down, the quantity of rice that consumers are willing and able to buy increases. This relationship is known as the law of demand, which states that there is an inverse relationship between the price of a product and the quantity of the product that consumers are willing and able to buy.

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A farmer who applies gypsum on his farmland intends to decrease soil acidity. Gypsum is a mineral that contains calcium and sulfur. When applied to soil, it reacts with soil particles and releases calcium ions, which replace the acidity-inducing hydrogen ions. As a result, the soil pH is increased, making the soil less acidic. This process is also known as liming, which is often used to improve soil fertility, increase crop yield and control soil-borne diseases.

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The hormone responsible for milk let-down in cows is oxytocin. Oxytocin is produced in the hypothalamus and stored in the pituitary gland. When a cow is stimulated by the presence of her calf or milking machine, oxytocin is released into her bloodstream. Oxytocin causes the muscles around the alveoli (tiny sacs within the mammary gland) to contract, pushing milk into the larger ducts and out of the teat. This process is known as milk let-down or milk ejection. Oxytocin is also known as the "cuddle hormone" because it is released during social bonding activities, such as hugging or touching, in humans and other mammals.

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Management is the factor determining the success of the production process in a farm enterprise. Good management practices can ensure efficient use of resources, maximize productivity and minimize wastage, leading to better profitability. Land, fixed assets and labor are important inputs, but it is the effective management of these resources that can lead to the successful production of crops or livestock.

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Salting and sun drying are the cheapest methods of preserving fish. Salting removes water from the fish, making it inhospitable to bacteria and other spoilage organisms. Sun drying involves exposing the salted fish to direct sunlight for several days to dry out the remaining moisture. This process helps to further inhibit bacterial growth and extend the shelf life of the fish. Both methods are inexpensive and can be done with minimal equipment, making them popular choices for small-scale fish processors and subsistence fishermen.

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The main aim of establishing game reserves is to prevent rare species of wild animals from extinction. Game reserves are established to protect wildlife and their natural habitats from destruction, hunting, and other human activities that could lead to their extinction. Game reserves are protected areas where wildlife is conserved for future generations, and they play an essential role in maintaining biodiversity and ecological balance. These reserves provide a safe haven for endangered species and help to preserve their genetic diversity. Through the protection of these species and their habitats, game reserves also contribute to the overall health of the ecosystem, which benefits both humans and wildlife.

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The mosaic appearance on cassava leaves is caused by a virus. The virus responsible for this is called the Cassava Mosaic Virus (CMV). It is spread by whiteflies and affects the growth and development of the cassava plant, leading to a reduction in yield. The virus infects the leaves of the cassava plant, causing them to develop a mosaic pattern of light and dark green patches, and may also cause the leaves to curl and become distorted.

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The recommended agricultural practice in a farm settlement scheme is mixed farming. Mixed farming involves the practice of growing crops and raising animals on the same farm. This type of farming has a lot of benefits, including reduced risks associated with single-crop farming, improved soil fertility through the use of animal manure, and a diversified income stream. Additionally, mixed farming provides food security and reduces the cost of production by using animal manure for fertilizer and reducing the need for external inputs. Therefore, mixed farming is the recommended agricultural practice in a farm settlement scheme.

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The Land Use Decree of 1978 vested lands in each state of Nigeria on the State Governors. The decree, also known as Decree No. 6 of 1978, made all lands in Nigeria to be owned by the government, with the state governors as trustees of the land on behalf of the people. The decree was a major land reform that aimed to make land more accessible and available for agricultural and other developmental purposes. With the decree, the state governors became responsible for the allocation and management of land within their respective states.

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Disease causing organisms are referred to as pathogens. Pathogens are microorganisms that cause diseases in plants, animals, and humans. Examples of pathogens include bacteria, viruses, fungi, and parasites. These microorganisms invade the host organism and cause damage to its cells and tissues, leading to illness or death. Pathogens can be spread through various means, such as through the air, contaminated water, contact with infected individuals, or through vectors like mosquitoes, ticks, and fleas.

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Nitrosomonas and Nitrobacter are responsible for nitrification in the nitrogen cycle. Nitrification is the process by which ammonium is converted to nitrite and then to nitrate by these bacteria. Nitrosomonas convert ammonium to nitrite while Nitrobacter convert nitrite to nitrate. This is an important step in the nitrogen cycle as it converts ammonia, which is toxic to most plants, to a form that is easily absorbed and used by plants.

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The major advantage of human power over all other sources of power is man's intelligence to control work. Human power is the energy that a person produces using their own body, and it can be harnessed in many ways, such as manual labor or pedaling a bicycle. Unlike other sources of power, such as machines or animals, humans have the ability to control their work and adjust their output to match the task at hand. This allows for greater precision and flexibility in a wide range of activities, from farming to manufacturing to transportation. While human power does have limitations in terms of strength and endurance, it remains a valuable source of energy due to the unique advantages of human intelligence and adaptability.

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Smut diseases are often found on maize. Smut diseases are fungal infections that affect various crops. However, maize is particularly susceptible to smut diseases caused by the fungus Ustilago maydis. The fungus attacks the kernels, causing them to become large, dark, and powdery. Smut-infected maize is often stunted and produces fewer kernels, which can lead to significant yield losses for farmers. Infected plants can also serve as a source of fungal spores that can spread the disease to neighboring fields.

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The intermediate host of liver fluke is a snail. When the eggs of liver fluke are passed out in the feces of infected animals, they hatch and release a free-swimming larval form known as miracidium. The miracidium then penetrates the snail's soft tissue and undergoes several developmental stages before being released as free-swimming cercariae. The cercariae, in turn, attach to grass or other vegetation, where they are ingested by grazing animals. The cercariae then move from the intestine to the liver and bile ducts of the animal, where they mature into adult flukes and begin producing eggs, thus completing the life cycle.

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The most important farm input contributed by the peasant farmer's family is labor. Peasant farmers usually rely on family labor for planting, weeding, harvesting, and other farm activities. Family labor is an important input because it is readily available, affordable and ensures the smooth running of farm activities. Peasant farmers often lack the financial resources to hire labor, so they rely on their family members for farm work. Moreover, family labor can be trusted and is often willing to work harder and longer hours to ensure that the farm tasks are completed on time. Therefore, labor is the most important farm input contributed by the peasant farmer's family.

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To calculate the amount of NPK fertilizer required for 15 hectares of maize farm, we need to find the total amount of fertilizer required for one hectare and then multiply it by the number of hectares. Given that 200kg of NPK fertilizer is required for one hectare of maize farm, the amount required for 15 hectares will be: 200 kg/ha x 15 ha = 3000 kg Therefore, the answer is 3,000 kg of NPK fertilizer required for 15 hectares of maize farm. Option (C) is the correct answer.

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Seedlings, calves, and chicks will appreciate in value on the farm. This is because they are living assets that grow and increase in value as they mature. Seedlings will grow into mature plants, calves will grow into adult cows or bulls, and chicks will grow into adult chickens that can be used for meat or egg production. Equipment, buildings, and machinery may hold their value, but they typically do not appreciate over time. Piglets and lambs may grow and gain weight, but they will eventually be sold for slaughter, meaning their value is not likely to increase over time.

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The question is asking to identify the type of pond that should NOT be included in a fresh water fish production system. A "storage pond" is not a common type of pond in a freshwater fish production system, as it is not used for the primary purpose of growing fish. Instead, it may be used for temporarily holding fish before processing or sale, or for storing water for use in the production ponds. Therefore, the answer is "storage pond".

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Progesterone is secreted by the corpus luteum. The corpus luteum is a temporary endocrine gland that is formed in the ovary after ovulation. It is responsible for the production and secretion of progesterone, which is a hormone that plays a crucial role in the menstrual cycle and pregnancy.

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The maintenance of osmotic balance in the body cells of animals is regulated by sodium and potassium. Osmotic balance refers to the balance of water and electrolytes (ions) inside and outside the cell. Sodium and potassium are both electrolytes that play vital roles in the body's fluid balance. Sodium ions are mainly found outside the cell while potassium ions are mainly found inside the cell. The concentration of these ions is regulated by specific transporters called ion channels and pumps, which help to maintain the balance between the inside and outside of the cell. This is important for many biological processes, including nerve and muscle function, and the regulation of blood pressure and volume.

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The correct option is "incidence of tse-tse flies". The equatorial rainforest belt is located in areas with a high prevalence of tse-tse flies, which are known to transmit diseases like trypanosomiasis (also known as sleeping sickness) to cattle. This makes it unsuitable for cattle production, as it poses a health risk to the animals. Additionally, the dense vegetative growth in the equatorial rainforest makes it difficult for cattle to graze, which further contributes to the unsuitability of this region for cattle production.

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The question is asking which of the following options is NOT included in government agricultural policies. The answer is "increasing the number of peasant farmers." This means that the government does not have a policy of increasing the number of peasant farmers. The other options listed are policies that governments may have to promote agriculture and related industries.

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The salvage value of an asset is the estimated resale value of the asset at the end of its useful life. In this case, the tractor was sold for N20,000.00 after 10 years of use, which means that its salvage value is N20,000.00. Therefore, the correct answer is N20,000.00.

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Parturition in the doe (rabbit) is referred to as "kindling". This term is specific to rabbits and refers to the process of giving birth to young rabbits, also known as kits. During kindling, the doe typically gives birth to multiple kits in a single litter, with litters ranging in size from 1-14 kits. The term "kidding" is used for goats, "lambing" for sheep, and "farrowing" for pigs.

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The option that is not an objective of pasture management is "the lowest possible dry matter yield of pasture." Pasture management involves the manipulation of grazing and forage resources to achieve certain goals. The other options are common objectives of pasture management. For example, having the most palatable mixture of pasture crops will encourage grazing animals to consume more and make efficient use of the available pasture. High leaf-stem ratio is also important as it is an indicator of forage quality, while achieving the best possible nutritive value of pasture ensures that the animals receive adequate nutrition for growth, reproduction, and maintenance. However, obtaining the lowest possible dry matter yield of pasture is counterproductive, as it will reduce the amount of forage available for animals to graze on, leading to lower productivity and potential negative impacts on the environment.

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Wood ash and oil palm bunches are rich sources of potassium. Potassium is an essential macronutrient required by plants for their growth and development. It plays a vital role in regulating water balance, strengthening plant cells, and improving resistance to diseases and stress. Wood ash is a byproduct of burning wood, while oil palm bunches are a residue of the oil extraction process from the fruit of the oil palm tree. Both of them are commonly used as organic fertilizers in agriculture due to their high potassium content.

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The amount of planting material needed for a given area of land is known as seed rate. It is the amount or weight of seeds required to plant a specific area of land. The seed rate varies depending on factors such as the type of crop, soil type, climate, and planting method. The seed rate is an important factor in determining crop yield and ensuring uniform plant spacing. A high seed rate may result in overcrowding and competition for nutrients, while a low seed rate may result in poor yield due to underutilization of the available resources.

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Banana blight is not a viral disease of crops. Banana blight is caused by a bacterium called Xanthomonas campestris. The disease affects banana plants and causes wilting and rotting of the plant's pseudostem and leaves.

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The agricultural programme that covers risk and uncertainties in agricultural business is the agricultural insurance scheme. This is because the agricultural insurance scheme is designed to protect farmers from financial losses due to various risks such as natural disasters, crop failure, and pest infestations. The scheme provides a form of indemnity to farmers who have suffered losses due to an insured peril. The indemnity helps to reduce the financial burden of the losses and enables farmers to recover from the impact of the loss. The other agricultural programmes such as the agricultural development project, river basin development authority, and farm settlement scheme do not provide risk and uncertainties coverage.

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Subsistence agriculture is a type of farming in which farmers produce only enough food to feed their families and themselves. The main goal is to produce enough food to survive, rather than to make a profit. Therefore, the surplus produced is usually small or nonexistent, and savings are also limited. As a result, farm sizes are typically small, and yields are not usually high.

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An area of land where fruit trees are grown is commonly called an orchard.

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Chemicals are not allowed in the harvesting of fish. Using chemicals can contaminate the water and the fish, making it unsafe for human consumption. The other options (nets, baskets, and traps) are commonly used in fish harvesting and do not pose a threat to the safety of the fish or consumers.

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The deficiency symptom peculiar to vitamin B in livestock is the loss of appetite and weight. Vitamin B plays an important role in metabolism and digestion of carbohydrates, proteins, and fats in livestock. A deficiency in vitamin B can result in a reduced appetite, weight loss, and stunted growth. Other symptoms may include muscle weakness, nervous disorders, and decreased milk production.

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The correct answer is "selective exploitation". Selective exploitation is a forestry management technique where only matured trees are cut down for timber or other uses while leaving the younger trees to continue growing. This technique helps to ensure the sustainability of the forest by maintaining a healthy balance between the amount of wood harvested and the growth of new trees. It is often practiced in natural forests where trees grow naturally without human intervention, and it is an alternative to clear-cutting which involves cutting down all trees in an area.

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(a) Government and Non-Governmental Organisations improving agriculture in West Africa

Six Government organisations:

• Ministry of Agriculture (Federal/State).
• Agricultural Development Programmes (ADPs).
• National agricultural research institutes (for example NIFOR, IAR, NRCRI).
• Bank of Agriculture / agricultural credit agencies.
• National Agricultural Extension and Research Liaison Services (NAERLS).
• Nigeria Agricultural Quarantine Service / commodity boards.

Four Non-Governmental Organisations:

• Food and Agriculture Organisation (FAO).
• International Institute of Tropical Agriculture (IITA).
• Sasakawa Global 2000.
• USAID / Oxfam (development partners).

(b) Five ways NGOs contribute to agricultural productivity

• They provide credit, grants and farm inputs to farmers.
• They train farmers and provide extension education on improved practices.
• They supply improved seeds, breeds and technology.
• They fund agricultural research and rural infrastructure.
• They help farmers form cooperatives and find markets for produce.

(c) Six ways science and technology have boosted crop production

• Development of improved, high-yielding and disease-resistant crop varieties.
• Use of chemical fertilizers to improve soil fertility and yield.
• Use of agro-chemicals (herbicides, pesticides) to control weeds and pests.
• Mechanisation with tractors and implements, speeding up operations.
• Irrigation technology allowing all-year cropping.
• Improved storage, processing and preservation techniques that reduce losses (and tissue culture/biotechnology for rapid multiplication).

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(a) Systems of breeding

(i) In-breeding: The mating of closely related animals, for example brother to sister or parent to offspring, within the same breed. It is used to fix and concentrate desirable characteristics and to produce pure lines, but if continued it can lead to inbreeding depression (loss of vigour and fertility).

(ii) Line-breeding: A milder form of in-breeding in which animals are mated to keep them closely related to one outstanding ancestor (for example grand sire to grand daughter), but not as close as parent-offspring mating. It aims to retain the good qualities of a superior ancestor while reducing the harmful effects of close in-breeding.

(iii) Cross-breeding: The mating of animals of two different breeds. It combines the desirable qualities of both breeds and produces offspring with hybrid vigour (heterosis), which are often more vigorous, faster growing and more productive than either parent.

(b) Three methods of collecting semen from a proven male for artificial insemination

• Use of an artificial vagina.
• Electro-ejaculation (electrical stimulation).
• Massage method (manual massage of the ampullae/rectal massage).

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(a) Percentage of early adopters and its implication

Total number of farmers = 10 + 15 + 70 + 25 = 120.

\[ \text{Percentage of early adopters} = \frac{15}{120} \times 100 = 12.5\% \]

Implication: Only a small proportion (12.5%) of the farmers readily accept new ideas early. This means the extension system is not very effective at getting farmers to adopt innovations, so the extension agents need to intensify their teaching, demonstrations and follow-up to speed up the rate of adoption in the village.

(b) Four ways of encouraging the innovators

• Give them recognition, awards and encouragement for trying new ideas.
• Supply them with improved inputs, credit and technical support.
• Use their farms as demonstration/result plots so others can learn from them.
• Provide regular training, information and visits by extension agents.

(c) Four possible reasons for the high number of late adopters

• Illiteracy and lack of access to information.
• Poverty/lack of funds to buy the new inputs.
• Strong attachment to tradition and fear of the risk of new methods.
• Inadequate extension contact and poor infrastructure (roads, markets).

(d) Two merits of print media as a channel for extension

• The information is permanent and can be kept and re-read for reference.
• It can reach many literate farmers over a wide area at relatively low cost.

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(a) The law of diminishing returns states that when additional equal units of a variable factor of production, such as fertilizer, are applied to a fixed factor, such as land, total output will initially increase at an increasing rate, then at a decreasing rate, and may eventually decrease.

(b) Completed table:

Size of farm (ha)	Quantity of fertilizer used (bags)	Yield of maize (bags)	Change in quantity of fertilizer (bags)	Change in yield of maize (bags)
2	0	8	-	-
2	8	24	8	16
2	12	48	4	24
2	16	80	4	32
2	20	120	4	40
2	24	150	4	30
2	28	170	4	20
2	32	180	4	10
2	34	180	2	0
2	36	170	2	-10

(c) Graph of yield of maize against quantity of fertilizer used:

The graph shows that from 0 to 20 bags of fertilizer, maize yield rises at an increasing rate: the successive increases in yield are 16, 24, 32 and 40 bags. This is the stage of increasing returns.

Beyond 20 bags, output still rises but at a decreasing rate. The increases in yield fall from 30 bags to 20 bags and then to 10 bags as fertilizer rises from 20 to 32 bags. This is the stage of diminishing returns.

At 34 bags of fertilizer, the yield is at its maximum of 180 bags and the additional yield is zero. When fertilizer is increased to 36 bags, yield falls from 180 bags to 170 bags, giving a negative return of 10 bags. Thus, after 20 bags of fertilizer, each further addition produces a smaller increase in maize yield, and excessive fertilizer eventually reduces output.

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(a) Seven economic importance of insect pests in crop production

1. They destroy crops in the field through sucking, boring, burrowing and defoliation activities.
2. They reduce crop yield and severe infestation may lead to total crop failure.
3. They reduce the quality, nutritional value and market value of crops and stored produce.
4. They make fruits and vegetables unattractive, damaged and unmarketable.
5. They increase the cost of production because farmers spend money on insecticides and other control measures.
6. They serve as vectors of plant diseases, especially viral diseases.
7. They reduce the viability and germination capacity of stored seeds and may cause storage losses.

(b) Two hosts of cotton stainer

1. Okra.
2. Kenaf.

(c) Soil-dwelling insect pests and general control measures

Two soil-dwelling insect pests of crops:

1. Termites.
2. Crickets.

Five general control measures of insect pests of crops:

1. Use resistant or tolerant crop varieties.
2. Practise crop rotation.
3. Spray or dust crops with recommended insecticides.
4. Treat seeds or planting materials with appropriate insecticides before planting.
5. Practise proper farm sanitation by removing crop residues, weeds and alternate host plants.

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Environmental factors in poultry production

(a) Temperature

Temperature affects feeding, growth, egg production and comfort of birds. Very high temperature causes heat stress, reduced feed intake, panting and lower egg production, while very low temperature (especially for chicks) causes chilling, huddling and death.

Two ways of controlling its effect:

• Provide brooders/heat sources (lamps) to warm chicks in cold conditions.
• Provide adequate ventilation, shade and cool clean water, and orientate/insulate the house to reduce heat.

(b) Relative humidity

High relative humidity makes litter damp and cakey, encourages ammonia build-up, moulds and disease, and hampers heat loss from birds. Very low humidity causes dusty conditions and dehydration.

Two ways of controlling its effect:

• Provide good ventilation (open sides, fans) to remove excess moisture.
• Keep the litter dry by regular turning/replacement and avoid water spillage.

(c) Light

Light stimulates activity, feeding and, importantly, the reproductive system, thereby influencing sexual maturity and the rate of egg laying. Too little light reduces egg production; excessive/uncontrolled light can cause restlessness and vices such as cannibalism.

Two ways of controlling its effect:

• Provide artificial (electric) lighting to supplement day length and stimulate laying.
• Regulate the light duration and intensity using timers, dimmers or by curtaining/shading the house.

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(a) Plant nutrients

(b) Two examples of nitrogenous fertilizers

• Urea.
• Ammonium sulphate (also calcium ammonium nitrate).

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(a) Four ways ornamental plants are important

• They beautify the environment (homes, offices, gardens and streets).
• They are used for landscaping and to provide shade.
• They serve as windbreaks, hedges and boundary/screen plants.
• They are a source of income when sold and help purify the air, reducing pollution.

(b) Examples

(i) Ornamental trees: Royal palm, flamboyant (flame of the forest), frangipani.

(ii) Ornamental shrubs: Hibiscus, croton, ixora, bougainvillea.

(c) Explanations

(i) Pasture: Land covered with grasses and/or herbaceous legumes that is grazed directly by livestock, or the herbage itself grown for grazing.

(ii) Forage: The vegetative parts of plants (grasses and legumes) that are eaten by livestock, either grazed fresh in the field or cut and served as hay or silage.

(d) Four roles of legumes in agriculture

• They fix atmospheric nitrogen through root nodule bacteria (Rhizobium), enriching the soil.
• They serve as cover crops that protect the soil from erosion and conserve moisture.
• They provide high-protein food for humans and fodder for livestock.
• They add organic matter (green manure) that improves soil structure and fertility.

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(a) Definitions

(i) Taungya farming: A system of forestry in which farmers are allowed to grow food/arable crops in-between young forest tree seedlings on the same piece of land during the early years of the plantation, tending the trees until the canopy closes.

(ii) Crop rotation: The practice of growing different types of crops in a definite order (sequence) on the same piece of land over successive seasons or years to maintain soil fertility and control pests and diseases.

(b) Four advantages of taungya farming

• It provides food crops and income to the farmer while the trees are young.
• It reduces the cost of establishing and maintaining the forest plantation (weeding is done free by farmers).
• It makes better use of land and sunlight in the early years.
• It provides employment and helps control weeds around the tree seedlings.

(c) Four principles underlying the choice of a crop rotation system

• Deep-rooted crops should follow shallow-rooted crops.
• Leguminous crops should be included to restore soil nitrogen.
• Crops of the same family (with similar pests/diseases) should not follow one another.
• Heavy feeders should be followed by light feeders or soil-restoring crops, and cover crops included to protect the soil.

(d) Four advantages of crop rotation

• It maintains and improves soil fertility.
• It controls the build-up of pests, diseases and weeds.
• It reduces soil erosion and improves soil structure.
• It gives higher and more varied yields and income.

(e) Situations under which crop rotation is recommended

Crop rotation is recommended where land is limited and must be cropped continuously, where there is a build-up of soil-borne pests and diseases, where soil fertility is declining, and where the farmer wants a steady supply of varied produce without leaving land to fallow.

Akọwa Nkọwa

(a) The Gunter's chain

The Gunter's chain is a land-measuring (surveying) chain that is 66 feet (about 20.1 m) long and made up of 100 links, each link being 7.92 inches. It is used to measure horizontal distances on farmland during chain surveying. Ten square chains make one acre, which makes it convenient for computing land area.

(b) Area of the triangular farm

The measurements must be in the same unit. Perpendicular length = 1200 m = 1.2 km, base = 2 km.

\[ \text{Area} = \tfrac{1}{2} \times \text{base} \times \text{perpendicular height} \]

\[ \text{Area} = \tfrac{1}{2} \times 2\,\text{km} \times 1.2\,\text{km} = 1.2\,\text{km}^2 \]

(Equivalently \(\tfrac{1}{2} \times 2000\,\text{m} \times 1200\,\text{m} = 1{,}200{,}000\,\text{m}^2 = 120\ \text{hectares}\).)

(c) Four precautions to eliminate errors when chaining

• Keep the chain straight, taut and horizontal during measurement.
• Use ranging poles to keep the line straight between the two points.
• Count the arrows/pins carefully and record readings correctly to avoid miscounting a chain length.
• Check the chain for stretched, bent or missing links before use and correct for sag and slope.

(d) Four factors in choosing a site for a new school garden

• Fertile, well drained soil.
• Nearness to a reliable source of water.
• Nearness to the school and accessibility.
• A fairly level, gentle land free from erosion, with adequate sunlight.