WAEC SSCE - Agricultural Science - 2011

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The layer of the soil profile where most biological activities occur is the A-horizon. This is the top layer of the soil, also known as the topsoil, which is rich in organic matter and nutrients. It is in this layer that plant roots grow, microorganisms thrive and decompose organic materials, such as dead leaves and animal remains. The A-horizon is essential for supporting plant growth and providing nutrients for agriculture, forestry and other land uses.

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Sub-surface irrigation is an irrigation technique where water is applied below the soil surface directly to the roots of the crops. Some of the advantages of sub-surface irrigation include that it reduces the rate of evaporation, conserves water, and reduces weed growth. However, the option that does not fit as an advantage of sub-surface irrigation is that "it can be used only for specific types of crops." This is because sub-surface irrigation can be used for a wide range of crops and is not limited to specific types.

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The insect that transmits swollen shoot disease of cocoa is the mealybug. Mealybugs are small, soft-bodied insects that are covered in a white, waxy powder. They feed on plant sap, and when they feed on cocoa trees, they can transmit the virus that causes swollen shoot disease. Swollen shoot disease is a serious viral disease that can cause stunted growth and death of cocoa trees. It is therefore important to control mealybug populations in cocoa farms to prevent the spread of the disease.

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Poaching is prohibited in game reserves to conserve wildlife. Game reserves are areas of land set aside for the conservation of wildlife and are protected by law. Poaching refers to the illegal hunting or capturing of wildlife, which can be detrimental to the survival of species and disrupt the natural ecosystem. Therefore, the prohibition of poaching in game reserves aims to conserve wildlife by protecting them from illegal hunting activities.

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The correct answer is Exoriepus. This is because calopogonium, pueraria, and centrosema are all leguminous crops that can fix atmospheric nitrogen in their root nodules with the help of symbiotic bacteria. The nitrogen fixed by the bacteria is converted to nitrates in the soil, thus enriching the soil with nitrates. However, Exoriepus is not a leguminous crop and does not have the ability to fix atmospheric nitrogen. Therefore, it cannot enrich the soil with nitrates.

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To start an oil palm plantation, a farmer should obtain a long-term loan. This is because oil palm trees take several years to mature and start producing fruit, usually between three to four years. Thus, the farmer will need a loan that provides enough time for the trees to mature and begin producing income. A long-term loan typically has a repayment period of more than one year and allows the borrower to repay the loan over an extended period, usually with a lower interest rate than short-term loans. It provides the farmer with the necessary funds to purchase land, prepare the land, purchase seedlings, pay for labor, and other expenses required for the initial plantation establishment. In summary, a long-term loan is the most appropriate type of loan for starting an oil palm plantation.

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The main function of an agricultural extension agent is to educate farmers on innovations in agriculture. Agricultural extension agents are trained professionals who provide farmers with knowledge and skills to improve their farm productivity, income and overall livelihood. They educate farmers on new agricultural techniques, technologies, and practices that can help them to increase their yield, reduce their production costs, and improve the quality of their products. Agricultural extension agents also provide information on market opportunities, government policies, and other factors that can affect farmers' livelihoods. Their main goal is to help farmers become self-sufficient, profitable, and sustainable in their farming practices.

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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 a tool that uses the Earth's magnetic field to determine the direction of North, South, East, and West. The surveyor would use the magnetic compass to align the base line in the direction he or she desires before taking measurements. The other options, such as the abney level, ranging pole, and plumb bob, are surveying tools, but they are not used specifically for determining the direction of a base line.

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To calculate the interest to be paid on the borrowed capital, we can use the simple interest formula: Interest = Principal * Rate * Time Where: - Principal = D50,000.00 (the borrowed capital) - Rate = 5% (the interest rate) - Time = 1 year Plugging in the values: Interest = 50,000.00 * 0.05 * 1 Interest = 2,500.00 Therefore, the interest to be paid on the borrowed capital after one year is D2,500.00. The correct option is (a) D2,500.00.

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The disadvantage of human power among the given options is that it has low output. Human power is limited to the strength and endurance of the person using it, which is often not enough to power certain equipment or perform heavy tasks efficiently. This makes it a less productive option compared to other sources of power such as machinery, animals or engines that can produce higher levels of output.

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Yolk sac infection, coccidiosis, and pullorum are diseases that commonly occur during brooding. Fowlpox is not a disease that is commonly associated with brooding. Therefore, the correct option is (b) I, II and IV only.

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A sow that is not producing milk after farrowing should be given oxytocin. Oxytocin is a hormone that stimulates milk letdown in lactating animals. When a sow has difficulty producing milk after farrowing, it could be due to inadequate hormonal stimulation. In such a situation, oxytocin injection is administered to stimulate the release of milk from the mammary glands, and this helps the piglets to receive the necessary nutrition.

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The correct sequence of feed utilization in farm animals is ingestion, digestion, absorption, and assimilation. First, the animal ingests or eats the feed. The food then undergoes digestion in the stomach and intestines, where it is broken down into smaller particles and nutrients. These nutrients are then absorbed by the small intestine and transported to the bloodstream. Finally, the nutrients are assimilated or used by the body for energy, growth, and maintenance of various bodily functions. It is important to note that proper nutrition is crucial for farm animals to maintain good health, maximize growth, and produce high-quality products such as meat, milk, and eggs.

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Yellow coloration of the lower leaves of a growing maize plant may be due to a deficiency in nitrogen. Nitrogen is an essential nutrient required by maize plants to grow and develop properly. When there is a lack of nitrogen in the soil, the plant will not be able to produce enough chlorophyll, which is responsible for the green color in plants. This will cause the lower leaves to turn yellow due to chlorosis. Therefore, a deficiency in nitrogen can lead to yellowing of the leaves in maize plants.

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Bush burning refers to the practice of intentionally setting fire to an area of uncultivated land. Although this practice can have some benefits, such as clearing land for agriculture or reducing the risk of wildfires, it also has many negative effects. One of the most significant of these negative effects is that bush burning destroys soil organic matter. Soil organic matter is an important component of healthy soil, as it provides nutrients for plants and helps to retain moisture. When the soil organic matter is destroyed by bush burning, it can take many years for it to be replenished. This can lead to reduced soil fertility, decreased crop yields, and other problems. Therefore, it is important to avoid or minimize the practice of bush burning in order to maintain healthy soil and sustainable agriculture.

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The regulatory control of diseases in crop production refers to the steps taken to prevent and manage the spread of diseases that affect crops. Out of the options given, the best answer is "quarantine." Quarantine is a process of isolating plants or crops that are suspected to be infected with a disease, to prevent the spread of the disease to other healthy plants. By separating infected plants from healthy ones, the disease is prevented from spreading further, and the healthy plants can continue to grow unaffected. Option A, "rouging," refers to the process of removing and destroying infected plants or parts of plants from the crop to prevent the disease from spreading. This method is effective when the disease is localized, but it may not be practical when dealing with large-scale infections. Option C, "crop rotation," involves the planting of different crops in a particular field in different seasons to reduce the buildup of pathogens that are specific to a particular crop. This method is useful in reducing the incidence of soil-borne diseases, but it may not be effective in controlling airborne diseases. Option D, "soil tillage," refers to the mechanical manipulation of the soil to create favorable conditions for the growth of crops. While soil tillage may help control some soil-borne diseases, it may also increase the risk of soil erosion and nutrient loss. In summary, quarantine is the most effective regulatory control measure for diseases in crop production.

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The correct sequence for the use of coupled implements for land preparation is plough, harrow, and ridger. Ploughing is the first operation in land preparation. It involves breaking the soil and turning it over to a certain depth. After ploughing, the soil is left in loose clods, and the next operation is harrowing. Harrowing helps to level the soil, break the clods into smaller pieces, and remove weeds and other unwanted debris from the soil surface. Once harrowing is done, the soil is ready for ridging. Ridging is the process of making raised beds or ridges on which crops are grown. It is done to improve drainage and aeration of the soil, especially in areas with heavy rainfall or poor drainage. Therefore, the correct sequence for the use of coupled implements for land preparation is ploughing, harrowing, and ridging.

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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 system is a form of agroforestry that is commonly used in tropical regions. Farmers plant food crops like maize, beans, or cassava in between rows of newly planted trees. As the trees grow, they provide shade for the crops and help to prevent soil erosion. Once the trees have matured, they can be harvested for timber or other forest products, and the cycle can begin again. This system benefits both the environment and the local communities, as it provides food and income while also promoting the sustainable management of forest resources.

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The soil water that is available for root absorption at field capacity is capillary water. Capillary water is held in the soil pores by capillary forces and is available for plant roots to absorb. At field capacity, the soil is filled with water and excess water has drained away, leaving capillary water in the soil pores. Hygroscopic water is bound too tightly to the soil particles to be available to plants, gravitational water drains quickly out of the soil, and superfluous water is water that exceeds the soil's holding capacity and can lead to waterlogging.

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Piglet anaemia is a condition where newborn piglets lack enough iron in their bodies, leading to poor growth, weakness, and even death. The most effective way to control piglet anaemia is by using iron drugs. Iron injections or oral iron supplements can be given to the piglets soon after birth to prevent or treat anaemia. Sulphur drugs, anthelmintics, and antibiotics are not effective in controlling piglet anaemia. Sulphur drugs are used to treat bacterial infections, anthelmintics are used to control parasitic worms, and antibiotics are used to treat bacterial infections.

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Tsetse flies are of economic importance in livestock production because they transmit trypanosomes, which are protozoan parasites that cause a group of diseases called trypanosomiasis or sleeping sickness. These diseases affect both domestic and wild animals, causing significant economic losses due to reduced productivity, morbidity, and mortality. Additionally, trypanosomiasis can also infect humans, causing serious health problems and sometimes even death. Therefore, controlling tsetse flies is essential to prevent the spread of trypanosomes and improve animal and human health.

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Micro-nutrients are required by plants in very small quantities. These nutrients are essential for plant growth and development, but are needed in smaller amounts compared to macro-nutrients like nitrogen, phosphorus, and potassium. Some examples of micro-nutrients include iron, manganese, zinc, copper, boron, and molybdenum. These nutrients play important roles in various plant processes such as photosynthesis, enzyme activation, and hormone regulation. Deficiencies in micro-nutrients can lead to stunted growth, decreased yield, and even plant death. Therefore, it is important to ensure that plants have adequate amounts of micro-nutrients to thrive.

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Sexual maturity in farm animals is not influenced by their breed, sex or weaning age, but it can be influenced by their nutrition. Adequate nutrition is essential for proper growth and development of the reproductive system in animals, which in turn affects their sexual maturity. Therefore, animals that are well-nourished are more likely to reach sexual maturity at the appropriate age compared to animals that are malnourished or undernourished.

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The use of animal traction, which involves using animals to pull farm equipment, is limited in the forest zones of West Africa due to the presence of tsetse flies. These flies transmit trypanosomiasis, a disease that affects both humans and animals. The disease can be fatal to animals and can also cause drowsiness and decreased work capacity, making it difficult for animals to work on farms. As a result, farmers in forest zones rely more on manual labor or the use of machines for farming activities.

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The false statement about soil organisms is that "soil with good texture and structure cannot harbour soil microbes." This statement is false because the texture and structure of soil play an important role in creating a favorable environment for soil organisms to thrive. Soil texture refers to the size of the mineral particles that make up the soil, while soil structure refers to the arrangement of these particles into aggregates. A soil with good texture and structure will have a balance of pore space and water retention that will support the growth and survival of soil microbes. Therefore, the statement that good soil texture and structure cannot harbor soil microbes is false.

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The causes of deforestation in West Africa are factors that contribute to the loss of forest cover in the region. Deforestation is the conversion of forested land to non-forested land, which may occur due to human activities or natural causes. The factors that contribute to deforestation in West Africa are typically related to human activities such as agriculture, urbanization, and logging. I. Expansion of cultivated land is a major cause of deforestation in West Africa. As the population grows and demand for food increases, farmers clear more land for agriculture. This can lead to the destruction of forests, as trees are cut down to make way for crops. II. High population growth rate is also a contributing factor to deforestation in West Africa. With a growing population, there is a greater demand for food, housing, and other resources, which can lead to the destruction of forests. As the population grows, there is also more pressure to convert forested land to agricultural or urban areas. III. Conservation of wildlife in game reserves is not a cause of deforestation. Game reserves are areas that are set aside for the conservation of wildlife, and are typically not used for agriculture or urban development. As such, they do not contribute to deforestation. IV. Urban growth is a contributing factor to deforestation in West Africa. As cities grow, there is a greater demand for resources such as wood and other building materials. This can lead to the destruction of forests as trees are cut down to meet the demand for these resources. Therefore, the correct option is (c) I, II, and IV only.

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The correct answer is "ascaris." Ascaris is a type of parasite that lives inside the body of its host. Specifically, it lives in the small intestine of humans and other animals. Ascaris is a type of roundworm that can grow up to 35 cm long and lay up to 200,000 eggs per day. These eggs are passed out of the host's body through their feces, which can then contaminate soil and water sources, leading to further infections. Mites, lice, and ticks are external parasites that live on the outside of their hosts. Mites are typically found in skin, hair follicles, and other areas on the surface of the host's body. Lice are commonly found on the hair and scalp of humans and other mammals. Ticks are known for burrowing into the skin of their hosts, where they can feed on blood for extended periods of time. To put it simply, Ascaris is the only option that lives inside the body of its host, specifically in the small intestine. The other options - mites, lice, and ticks - are external parasites that live on the outside of their host's body.

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Corms, rhizomes, and tubers are examples of underground stems. Underground stems are stems that grow below the ground and serve to anchor the plant, store food and water, and propagate new plants. Corms are thickened, vertically oriented, underground stems, such as those found in crocuses and gladioli. Rhizomes are horizontal stems that grow underground, such as those found in ginger and bamboo. Tubers are enlarged structures on the ends of underground stems that store nutrients, such as those found in potatoes.

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Grafting is a process used in crop production that involves the joining of two parts of related crops. The process involves cutting a stem or bud from one plant and attaching it to the rootstock of another plant. The two parts are then secured together until they grow together and form a single plant. Grafting is commonly used to propagate plants with desirable characteristics or to repair damaged plants.

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Agriculture contributes to the economy of West African Countries in many ways, including job creation, foreign exchange earnings, and the provision of raw materials to industries. However, it does not supply armaments for territorial defence. Armaments refer to weapons and military equipment, which are not typically produced through agricultural activities. Therefore, the correct answer is "supply of armaments for territorial defence."

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When a tall (TT) crop is crossed with a dwarf (tt) crop, the resultant crop will be 100% tall (Tt) in the first generation of offspring. This is because tallness (T) is dominant over dwarfness (t), meaning that even if one copy of the tallness gene is present (Tt), the plant will exhibit the tall phenotype. Therefore, all of the offspring in the first generation will be heterozygous (Tt) and tall. If two of these heterozygous plants (Tt) are crossed, the resulting offspring may be tall (TT), dwarf (tt), or heterozygous and tall (Tt) in a 1:2:1 ratio, respectively. This is known as a monohybrid cross and follows Mendelian genetics.

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Under the commercial land tenure system, farmers find it difficult to secure loans because land holdings cannot be used as security. In this system, land is often owned by large-scale commercial farmers, who have greater resources and can more easily use their land as collateral for loans. Small-scale farmers, who often work on leased land or own small plots, are not able to provide the same level of collateral and therefore struggle to secure loans. This makes it more difficult for them to invest in their farms and improve their productivity, which can perpetuate poverty and contribute to food insecurity.

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Basalt, granite and pumice are rocks formed as a result of volcanic eruption. When volcanoes erupt, molten lava and ash are released. These materials cool and solidify to form rocks. Basalt is a dark-colored fine-grained rock, formed from the cooling of lava. Granite is a coarse-grained rock formed from the slow cooling of magma deep underground. Pumice is a light-colored rock that forms from the cooling of frothy lava with trapped gas bubbles. Therefore, option B is the correct answer.

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Crop rotation decreases the incidence of pests by breaking the life cycles of pests. Crop rotation is the practice of growing different crops on a particular piece of land in a planned sequence over time. Different crops have different nutrient requirements and host different pests and diseases. Crop rotation interrupts the life cycles of pests and diseases by removing their hosts from the field, thereby reducing their populations. Pests and diseases that may have built up in the soil or on crop residues can be reduced or eliminated by growing crops that are not their hosts in the rotation. As a result, the likelihood of a pest or disease outbreak is reduced, and the overall health of the soil and crops is improved.

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Pineapple is widely propagated using suckers. A sucker is a vegetative shoot that arises from the base of the pineapple plant. It is an exact replica of the mother plant and has the same genetic makeup. Propagation using suckers is advantageous because it allows for the production of uniform plants that are disease-resistant, high-yielding, and mature earlier. The suckers are detached from the mother plant and planted in soil or any other suitable growing medium. Within a short period, the sucker will develop roots and start to grow, producing new fruit after about 18 months.

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When a tall (TT) crop is crossed with a dwarf (tt) crop, the resulting first filial generation (F1) will all be Tt (tall). This is because tallness is dominant over dwarfness. When these F1 individuals are crossed with each other, the genotypic ratio of the second filial generation (F2) will be 1 TT : 2 Tt : 1 tt. This is because each parent in the F1 generation can contribute either a T or t allele, resulting in four possible genotypes for the offspring: TT, Tt, Tt, and tt. Therefore, the genotypic ratio of the F2 generation is 1:2:1 (TT:Tt:tt). So, the answer is 1:2:1.

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Ammonium nitrate cannot be used to neutralize soil acidity. This is because ammonium nitrate is an acidifying fertilizer, meaning that it lowers the pH of the soil when applied. The other options, wood ash, limestone, and calcium phosphosilicate, are all alkaline materials that can be used to neutralize soil acidity. Wood ash is a quick-acting source of potassium and calcium that also raises soil pH. Limestone and calcium phosphosilicate are both slow-acting sources of calcium that gradually raise soil pH over time.

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Ginger is propagated by using its rhizome. A rhizome is a modified stem that grows horizontally underground and produces roots and shoots from its nodes. When planting ginger, the rhizome is cut into pieces, each with at least one bud, and then planted in the soil. The rhizome will then sprout and develop into a new ginger plant. This method of propagation allows for the production of genetically identical plants, which ensures consistency in the crop yield and quality.

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The correct answer is the "price of cowpea." The demand for cowpea by consumers is primarily determined by its price. As with any product or commodity, the higher the price, the lower the demand, and vice versa. Consumers tend to buy more cowpea when the price is low and less when the price is high. This is because when the price is high, it becomes more expensive for consumers to buy, which may cause them to look for alternative products or reduce their consumption of cowpea. While the income of consumers is also a factor that can influence demand, it is not as important as the price of cowpea. Even if consumers have a high income, they may still be unwilling to pay a high price for cowpea, which could result in lower demand. Similarly, while the taste of consumers is a consideration, it is not as significant a factor as price. If the price is too high, even consumers who enjoy the taste of cowpea may switch to alternative products. Finally, the supply of cowpea is not a factor that determines the demand for cowpea. Supply refers to the quantity of cowpea that is available in the market, while demand refers to the quantity of cowpea that consumers are willing to buy at a given price. The supply of cowpea may influence its price, but it does not directly determine the demand.

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The device which would help to stabilize heat in an incubator is a thermostat. A thermostat is an electrical device that controls the temperature of a system, such as an incubator, by sensing its temperature and activating a switch that turns heating or cooling devices on or off. In the case of an incubator, the thermostat maintains a constant temperature within the incubator, ensuring that the eggs or embryos inside are kept at the optimal temperature for development. This is important for successful incubation, as fluctuations in temperature can lead to poor hatch rates or other developmental problems. Therefore, a thermostat is a crucial component in an incubator for maintaining a stable temperature and ensuring successful hatching or development of eggs or embryos.

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Sugarcane has a fibrous root system. A fibrous root system is a type of root system that is made up of many small, branching roots that are roughly the same size. Sugarcane is a tall grass that grows in tropical and subtropical regions and has a fibrous root system that helps it to absorb water and nutrients from the soil efficiently. The other crops listed - cotton, coffee, and cowpea - have taproot systems or a combination of taproot and fibrous root systems.

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A young female cattle which has never calved is known as a "heifer". A heifer is a female cow that has not yet given birth to a calf. They are usually raised for breeding purposes and are kept until they reach maturity and are ready to mate with a bull. Once they have given birth to their first calf, they are no longer considered heifers and are referred to as cows.

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The main objective of establishing forests in arid regions is to check desert encroachment. Arid regions are areas with low rainfall and vegetation cover. These areas are prone to desertification due to human activities such as overgrazing, deforestation, and poor land use practices. Forest establishment in arid regions helps to combat desertification by improving soil fertility, preventing soil erosion, and increasing vegetation cover. Forests act as a barrier to the encroachment of deserts, helping to maintain ecological balance and preserve biodiversity. Therefore, the establishment of forests in arid regions is critical for environmental sustainability and the prevention of desertification.

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Newly-born rabbits are called "bunnies". This term is commonly used to refer to young rabbits, especially those that are still very small and have not yet developed their full set of features. The term "bunny" is often used interchangeably with "kit" or "kitten" to refer to the young of many other animals, such as cats.

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Land in agricultural business is a durable asset because its value is realized over several years. Land can be used for many years and the value of the land as an asset is not realized in a short period of time. Unlike labour, which can be depleted or worn out, land can be used for a long time to produce crops, livestock, and other agricultural products. Land can also appreciate in value over time, making it a valuable asset for agricultural businesses. While land can be expanded by reclamation, this is not the primary reason why it is considered a durable asset. Finally, land is not a free gift of nature, as it often has to be acquired and developed for agricultural purposes, which can be a significant investment.

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The factor that does not influence the distribution of cattle in West Africa is "light". Light does not have a direct influence on the distribution of cattle as they are not dependent on it for survival. Factors such as pastures, diseases, and rainfall are important in determining the distribution of cattle in West Africa. The availability of pastures and water resources, for instance, influence where the cattle can graze and sustain themselves. Diseases can also impact the distribution of cattle by limiting their ability to survive in certain regions. Rainfall is an important factor in determining the availability of pastures and water resources, and therefore, also plays a significant role in the distribution of cattle.

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In preparing for parturition (giving birth) of a sow (female pig), warmth should be provided to prevent chilling of the young piglets. During birth, the piglets are wet and can easily become cold, which can lead to hypothermia and other health problems. Providing warmth can help prevent this and ensure the piglets have a good start in life.

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(a) Ten differences between subsistence and commercial agriculture

(b) Sources of farm power

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(a) Soil consistency

Soil consistency is the degree of resistance of the soil to deformation or rupture, that is the strength with which soil particles hold together (cohesion) and stick to other objects (adhesion) at different moisture contents. It is described as loose, friable, firm or hard when dry, and as sticky and plastic when wet.

(b) Influence of soil properties on crop growth

(i) Soil texture: texture refers to the relative proportion of sand, silt and clay. It determines how much water and air the soil holds and how easily roots penetrate. Sandy (coarse) soils drain fast and dry quickly, holding few nutrients, while clayey (fine) soils hold much water and nutrients but may become waterlogged and poorly aerated. A well balanced loam gives the best water, air and nutrient supply for crop growth.

(ii) Soil pH: pH measures the acidity or alkalinity of the soil. It controls the availability of plant nutrients; most crops grow best at slightly acidic to neutral pH (about 6 to 7). Very acidic or very alkaline soils lock up nutrients, may release toxic elements, and reduce the activity of beneficial soil micro-organisms, thereby limiting crop growth.

(c)(i) Four methods of maintaining soil fertility

1. Application of organic manure
2. Application of inorganic (chemical) fertilisers
3. Crop rotation
4. Cover cropping/green manuring (mixed farming and fallowing are also acceptable)

(c)(ii) How each method maintains soil fertility

• Organic manure: adds nutrients to the soil, and improves soil structure, aeration and water-holding capacity.
• Inorganic fertiliser: supplies specific nutrients (N, P, K) quickly, and corrects identified nutrient deficiencies to boost yield.
• Crop rotation: alternating deep- and shallow-rooted crops uses nutrients from different soil depths, and including legumes fixes nitrogen while breaking the pest and disease cycle.
• Cover cropping/green manuring: protects the soil from erosion and adds organic matter, and legume cover crops fix atmospheric nitrogen into the soil.

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(a) Four ways in which rangeland is important in livestock production

1. Source of cheap natural feed: rangeland supplies natural pasture (grasses and legumes) which grazing animals feed on directly, greatly reducing the cost of buying feed.
2. Supply of water: streams, ponds and other natural water sources found within the rangeland provide drinking water for the livestock.
3. Space for exercise and free movement: the open land gives the animals room to move about and exercise, which keeps them healthy and reduces stress.
4. Shelter and shade: the scattered trees and shrubs on the rangeland provide shade and protection against harsh weather (sun, wind and rain).

(Also acceptable: habitat and breeding ground for natural mating; source of mineral licks and medicinal plants.)

(b) Carrying capacity of the rangeland

From the diagram, the rangeland is a stadium shape: a central rectangle with a semicircular end on each side.

• Length of the straight (rectangular) portion \(= 250\,\text{m}\)
• Width \(= 114\,\text{m}\), so each semicircle has diameter \(114\,\text{m}\) and radius \(r = \dfrac{114}{2} = 57\,\text{m}\)

Step 1: Area of the rectangular portion

\[A_{\text{rect}} = L \times W = 250 \times 114 = 28{,}500\,\text{m}^2\]

Step 2: Area of the two semicircular ends

The two equal semicircles together make one full circle of radius \(57\,\text{m}\). Taking \(\pi = \dfrac{22}{7}\):

\[A_{\text{circle}} = \pi r^2 = \frac{22}{7} \times 57^2 = \frac{22}{7} \times 3249 = 10{,}211.14\,\text{m}^2\]

Step 3: Total area of the rangeland

\[A_{\text{total}} = 28{,}500 + 10{,}211.14 = 38{,}711.14\,\text{m}^2\]

Step 4: Convert to hectares \((1\ \text{hectare} = 10{,}000\,\text{m}^2)\)

\[A_{\text{total}} = \frac{38{,}711.14}{10{,}000} = 3.87\,\text{hectares}\]

Step 5: Carrying capacity

Recommended grazing area per cattle \(= 3\,\text{m} \times 3\,\text{m} = 9\,\text{m}^2\).

\[\text{Carrying capacity} = \frac{\text{Total area}}{\text{Area per cattle}} = \frac{38{,}711.14}{9} = 4301.2\]

Since a fraction of an animal is not counted, the rangeland (about 3.87 hectares) can carry 4301 cattle.

(If the shape is read as a rectangle with only one semicircular end, the area \(= 28{,}500 + \tfrac{1}{2}(10{,}211.14) = 33{,}605.57\,\text{m}^2 = 3.36\ \text{ha}\), giving a carrying capacity of \(3733\) cattle.)

(c) Two benefits of each management practice

(i) Dipping

• Controls external parasites such as ticks, lice and mites on the skin and coat of the animal.
• Prevents parasite-borne diseases (for example anaplasmosis, babesiosis and heartwater) and keeps the hide healthy.

(ii) Vaccination

• Confers immunity, protecting the animal against specific infectious diseases such as anthrax, blackleg and rinderpest.
• Reduces the death rate and checks the outbreak and spread of epidemic diseases within the herd.

(iii) Artificial insemination

• Allows the use of semen from superior, proven sires so that the genetic quality and productivity of the offspring are improved.
• Prevents the transmission of breeding (venereal) diseases spread during natural mating, and lets one superior bull serve many cows even over long distances.

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(a) Field pest versus storage pest

A field pest is a pest that attacks and damages crops while they are still growing on the farm (in the field), for example the grasshopper and stem borer, whereas a storage pest is a pest that attacks and damages harvested farm produce kept in storage, for example the weevil and rat.

(b) Two reasons for early harvesting of maize

1. To avoid damage and losses caused by field pests, birds and rodents.
2. To reduce spoilage from rain, mould and rotting and to prevent lodging of over-mature plants (early harvest of green maize also fetches a good market price).

(c) Methods of crop improvement

(i) Introduction: this is bringing in crop varieties or planting materials from another area or country where they have desirable qualities, and growing them in a new environment. If they perform well, they are multiplied and released to farmers.

(ii) Cross breeding (hybridisation): this is the deliberate mating (crossing) of two crop plants of different varieties, each having desirable qualities, so that the offspring combines the good qualities of both parents, for example high yield with disease resistance.

(d) Six factors to consider in selecting a crop variety

1. High yielding ability.
2. Resistance to pests and diseases.
3. Suitability to the local soil and climate.
4. Early maturing ability.
5. Market demand and consumer preference.
6. Tolerance to drought and adverse conditions (good storage/keeping quality is also acceptable).

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(a)(i) Agricultural extension

Agricultural extension is an informal, out-of-school educational service that teaches farmers improved and modern farming methods, carries the results of agricultural research to them, and helps them to solve their farm and home problems so as to raise their standard of living.

(a)(ii) Five demerits of cooperative societies

1. Poor and dishonest management can lead to loss or embezzlement of members' funds.
2. Many members are illiterate, which leads to poor record keeping and mismanagement.
3. Disagreement and lack of unity among members can break up the society.
4. Inadequate capital limits what the society can do for its members.
5. Delay in decision making because decisions are taken collectively (over-dependence on the society and undue government interference are also acceptable).

(b)(i) Three effects of rural-urban migration on agriculture

1. It causes shortage of farm labour because able-bodied young people leave the villages for the towns.
2. Farm output falls as farmland is left uncultivated or abandoned, leading to food shortage.
3. It leaves mostly the aged and weak to farm, so productivity and adoption of modern methods decline (cost of hired labour also rises).

(b)(ii) Three solutions to rural-urban migration

1. Provide social amenities such as good roads, water, electricity, schools and health centres in the rural areas.
2. Make farming attractive and profitable through mechanisation, credit, subsidies and good prices for produce.
3. Establish industries and create job opportunities in the rural areas to keep the youth on the land.

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(a)(i) Vegetative propagation

Vegetative propagation is the method of raising new plants from the vegetative parts of a parent plant such as the stem, root, leaf or bud (for example cuttings, suckers, tubers, bulbs, budding and grafting), without the use of seeds. The new plants are genetically identical to the parent.

(a)(ii) Advantages and disadvantages of vegetative propagation

Advantages:

1. The new plants keep exactly the good qualities of the parent plant.
2. Plants mature and bear fruit earlier than those raised from seed.
3. It is useful for propagating crops that produce few or no viable seeds.

Disadvantages:

1. It does not allow production of new/improved varieties (no genetic variation).
2. Diseases of the parent plant are easily passed on to the offspring.
3. The plants lack a tap root, are less vigorous and cannot be stored or transported over long distances as easily as seeds.

(b) Four cultural methods of controlling crop pests

1. Crop rotation.
2. Regular weeding and keeping the farm clean (field sanitation).
3. Early planting and early harvesting to escape pest attack.
4. Use of resistant varieties and proper spacing (destroying crop residues after harvest is also acceptable).

(c) Four harmful effects of chemical pest control

1. Chemicals may kill useful organisms such as bees, natural enemies and soil organisms.
2. They pollute the soil, water and air (environmental pollution).
3. Chemical residues on crops are poisonous and harmful to human and animal health.
4. Continuous use makes pests develop resistance to the chemicals.

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(a) Deep litter system of poultry management

Advantages:

1. Many birds can be kept together in one house, so it saves space and labour.
2. The litter (droppings and bedding) can later be used as valuable manure.
3. Birds are protected from bad weather, predators and theft, and eggs are cleaner and easily collected.

Disadvantages:

1. Diseases and parasites spread quickly among the closely kept birds.
2. Damp or dirty litter produces ammonia, bad odour and can cause respiratory diseases.
3. It requires high capital for housing, litter and feeding, and birds may develop vices such as cannibalism and egg eating.

(b) Reasons for animal husbandry practices

(i) Castration of goats

1. To make the animals docile and easy to handle.
2. To improve the quality and remove the offensive smell/taste of the meat.
3. To prevent indiscriminate/uncontrolled mating and to promote fattening.

(ii) Creep feeding of pigs

1. To supply extra nutrients to the piglets since the sow's milk is not enough.
2. To help the piglets grow fast and reach weaning weight early.
3. To accustom the piglets to solid feed and reduce the stress of weaning.

(c) Four local breeds of cattle reared in West Africa

1. White Fulani (Bunaji)
2. Sokoto Gudali
3. Red Bororo (Rahaji)
4. N'Dama (Muturu and Keteku are also acceptable)

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(a)(i) Farm credit

Farm credit is the money or resources borrowed by a farmer from a source such as a bank or cooperative, to be used for farming operations and repaid later, usually with interest, over an agreed period.

(a)(ii) Five sources of farm credit

1. Commercial banks
2. Agricultural/development banks (for example the Bank of Agriculture)
3. Cooperative societies
4. Government loans and grants
5. Money lenders, friends and relatives (thrift/esusu societies are also acceptable)

(b)(i) Three main extension teaching methods

1. Individual (person-to-person) method
2. Group method
3. Mass (mass media) method

(b)(ii) Most appropriate method for creating awareness about the disease outbreak

The mass (mass media) method is the most appropriate.

(b)(iii) Two reasons for the choice

1. It reaches a very large number of farmers over a wide area within a very short time, which is important because the disease is spreading fast.
2. It is quick and cheap per farmer reached, so the warning gets to everyone before the disease spreads further.

(b)(iv) Three problems in using the mass method

1. There is no personal contact, so farmers cannot ask questions or get their doubts cleared (no feedback).
2. The message may be too general and may not suit the individual conditions of each farmer.
3. Many rural farmers may not own radio/television or read newspapers, and the message may be misunderstood or ignored.

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(a)(i) Soil tillage

Soil tillage is the mechanical manipulation or working of the soil (by ploughing, harrowing, ridging, etc.) to loosen it, prepare a good seedbed, control weeds and create favourable conditions for planting and crop growth.

(a)(ii) Primary versus secondary tillage

Primary tillage is the first, deep and rough breaking of the land (for example ploughing) that opens up and loosens the soil, whereas secondary tillage is the lighter, shallow working done after primary tillage (for example harrowing and ridging) to break clods, level the soil and prepare a fine seedbed.

(b) Roles of soil management practices

(i) Green manuring

1. Adds organic matter and improves soil structure.
2. Increases soil nitrogen and fertility (especially when legumes are used).
3. Protects the soil surface from erosion and smothers weeds.

(ii) Mulching

1. Conserves soil moisture by reducing evaporation.
2. Controls weeds and moderates soil temperature.
3. Protects the soil from erosion and adds organic matter when it decays.

(c) Six reasons for irrigation in crop production

1. To supply water to crops during the dry season or periods of drought.
2. To make crop production possible all year round.
3. To supplement rainfall where it is inadequate or unreliable.
4. To dissolve and make soil nutrients and applied fertilisers available to crops.
5. To help in land preparation and softening of hard soil (as in paddy rice).
6. To reduce the harmful effects of high soil temperature and to leach out excess salts from the soil.

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(a) Contributions of science and technology

(i) Crop protection

1. Development of chemical pesticides, herbicides and fungicides for controlling pests, weeds and diseases.
2. Breeding of pest- and disease-resistant crop varieties.
3. Development of biological control methods and improved storage/spraying equipment to protect crops in the field and in store.

(ii) Climatology and meteorology

1. Accurate weather forecasting helps farmers to plan planting, spraying and harvesting.
2. Rainfall and temperature records guide the choice of crops and the timing of farm operations.
3. Early warning of drought, flood and storms allows farmers to take protective measures and reduce losses.

(b) Two functions of each farm machine/implement