Unit 5.1 Study Guide - Agriculture PDF

Unit 5.1 Study Guide - Agriculture Do NOT memorize the definitions for these terms. You should be able to explain, provide examples and/or apply the following terms to the scientific process. _______________________________________________________________________...

Unit 5.1 Study Guide - Agriculture Do NOT memorize the definitions for these terms. You should be able to explain, provide examples and/or apply the following terms to the scientific process. _______________________________________________________________________ Table of Contents Nutrient Cycles and The Green Revolution Irrigation Methods Soil Formation, Eutrophication and Agricultural Erosion, Composition, Practices and Properties Pest Control Methods Meat Production Sustainable and Integrated Pest Methods Agriculture Management (IPM) Soil Formation, Erosion, Composition, and Properties Soil Formation and Erosion ​ Parent Material: ○​ Soil begins to form when the underlying rock (parent material) is weathered (broken down), transported (moved), and deposited (laid down). ​ Soil Horizons: ○​ Soils are categorized into different layers, or horizons, based on their composition (minerals, organic matter) and organic content. ​ O Horizon: Organic layer, rich in decomposed plant material (humus). ​ A Horizon: Topsoil, a mixture of organic matter and minerals, crucial for plant growth. ​ E Horizon: Leaching layer, where minerals are leached out, typically lighter in color. ​ B Horizon: Subsoil, where minerals and nutrients accumulate from above layers. ​ C Horizon: Weathered parent material, consisting of partially disintegrated rock. ​ R Horizon: Bedrock, the unweathered rock layer beneath the soil. ​ Erosion:  ○​ Soil can be eroded through natural processes such as wind or water movement. Protecting soil is vital as it helps filter and clean water, maintaining water quality. Soil Composition and Properties ​ Water Holding Capacity: ○​ This refers to the total amount of water that soil can retain. Different soil types have varying capacities, which contribute to land productivity and soil fertility. ​ Particle Size and Composition: ○​ The size of soil particles (clay, silt, sand) and their arrangement in each horizon influence soil characteristics like porosity (space between particles), permeability (ease of water movement), and fertility (nutrient availability). ​ Testing Soil Properties: ○​ There are various methods to analyze the chemical (nutrients), physical (texture), and biological (microorganisms) properties of soil, which inform decisions regarding irrigation and fertilizer use. ​ Soil Texture Triangle: ○​ This is a graphical tool used to identify and categorize soil types based on their proportions of clay, silt, and sand. Nutrient Cycles and Eutrophication The Nitrogen Cycle ​ Main Points: ○​ Most nitrogen reservoirs hold compounds for a short duration. ○​ Nitrogen fixation is crucial for converting atmospheric nitrogen into forms usable by plants (primarily ammonia). ○​ The atmosphere is the primary reservoir for nitrogen. ​ Key Processes: ○​ Nitrogen Fixation: + ​ The conversion of atmospheric nitrogen (N₂) into ammonia (NH₃/NH4 ) by certain bacteria AND through natural processes like lightning. ○​ Ammonification ​ When decomposers break down organic matter, such as dead plants and + animals, into ammonia (NH₃/NH4 ) ○​ Nitrification: + ​ The process where ammonia (NH₃/NH4 ) is converted into nitrate (NO₃⁻) by bacteria, making it more accessible to plants.  ○​ Assimilation ​ The process by which living organisms, particularly plants, absorb nitrates + (NO₃⁻) and ammonia (NH₃/NH4 ) from the soil and incorporate them into organic molecules, such as amino acids and proteins, essential for their growth and development. ○​ Denitrification: ​ The conversion of nitrates (NO₃⁻) back into nitrogen gas (N₂) by bacteria, returning it to the atmosphere. The Phosphorus Cycle ​ Main Points: ○​ Major reservoirs are primarily rock and sediment containing phosphorus-bearing minerals. ○​ The phosphorus cycle lacks an atmospheric component, leading to natural scarcity in many ecosystems, often making phosphorus a limiting nutrient. ​ Key Processes: ○​ Weathering: ​ The breakdown of rocks releases phosphorus into the soil and water. ○​ Absorption/Uptake: ​ Plants absorb phosphate (PO₄³⁻) from the soil. ○​ Decomposition: ​ After organisms die, phosphorus is returned to the soil by decomposers. Eutrophication ○​ Eutrophication is the process of nutrient enrichment (specifically nitrogen and phosphorus) in bodies of water. ​ Algal Bloom: ○​ Increased nutrients lead to algal blooms. When these blooms decompose, microbes consume oxygen, resulting in lower dissolved oxygen levels. ​ Hypoxic Waterways: ○​ Water bodies with low dissolved oxygen are termed hypoxic, often leading to die-offs of aquatic life. ​ Comparison: ○​ Oligotrophic waterways have low nutrient levels, stable algae populations, and high dissolved oxygen, contrasted with nutrient-rich eutrophic waterways. ​ Anthropogenic Causes:  ○​ Agricultural runoff and wastewater discharge are significant human-influenced factors contributing to eutrophication. The Green Revolution and Agricultural Practices The Green Revolution ​ Overview: ○​ The Green Revolution involved the adoption of new agricultural strategies to enhance food production. It yielded both positive and negative consequences. Key Strategies and Practices: ​ Mechanization: ○​ The use of machinery in agricultural processes to improve efficiency and productivity. ​ Genetically Modified Organisms (GMOs): ○​ Organisms whose genetic material has been altered to achieve desired traits, such as improved yield or resistance to pests. ​ Fertilization: ○​ The application of chemical or organic substances to soil to enhance plant growth. ​ Irrigation: ○​ The controlled application of water to crops to aid in growth, especially in arid regions. ​ Pesticides: ○​ Chemicals used to eliminate pests that threaten crop production. Impacts of Mechanization: ​ Positive: ○​ Increased profits and farming efficiency. ​ Negative: ○​ Greater dependence on fossil fuels, contributing to environmental issues. Impacts of Agricultural Practices Environmental Damage ​ Certain agricultural methods can have damaging effects on the environment. Key practices that can lead to environmental harm include: ○​ Tilling: ​ The agricultural preparation of soil, which can disrupt soil structure and  lead to erosion. ○​ Slash-and-Burn Farming: ​ A technique of clearing land by cutting and burning vegetation, which can result in deforestation and loss of biodiversity. ○​ Use of Fertilizers: ​ Excessive use can lead to nutrient runoff into waterways, causing pollution and disrupting aquatic ecosystems. Summary ​ The Green Revolution introduced advanced agricultural techniques that significantly increased food production but also raised concerns about environmental sustainability. Mechanization, while increasing efficiency, has led to greater fossil fuel dependence. Additionally, certain agricultural practices can harm the environment, necessitating greater awareness and management in agricultural methodologies. Irrigation Methods Water Use for Irrigation: ​ The largest human use of freshwater is for irrigation, which accounts for approximately 70% of total freshwater consumption. Types of Irrigation: ​ Drip Irrigation: ○​ Most efficient method with only 5% water lost; uses perforated hoses to deliver water directly to plant roots. ○​ High initial cost, less commonly used. ​ Furrow Irrigation: ○​ Involves cutting furrows between rows of crops, filling them with water. ○​ Inexpensive, but about 33% of water is lost to evaporation and runoff. ​ Flood Irrigation: ○​ Fields are flooded with water, resulting in approximately 20% water loss due to evaporation and runoff. ○​ Can lead to soil waterlogging. ​ Spray Irrigation: ○​ Pumps groundwater into spray nozzles over the field, with 25% or less water loss.  ○​ More efficient and costly than flood and furrow methods; requires energy to operate. Water Issues: ​ Waterlogging: ○​ Excess water in soil raises the water table, hindering plants' oxygen absorption through roots. ​ Salinization: ○​ Salt buildup in soil due to evaporation of irrigated water; can become toxic to plants over time. ​ Aquifer Depletion: ○​ Overuse of aquifers for irrigation, exemplified by the severe depletion of the Ogallala Aquifer in the central U.S. Pest Control Methods and Integrated Pest Management (IPM) Consequences of Common Pest Control Methods: ​ Resistance Development: ○​ Common pest control methods (pesticides, herbicides, fungicides, rodenticides, insecticides) can lead to organisms developing resistance through artificial selection. ​ Crop Benefits: ○​ These methods reduce pest damage and increase crop yields. Genetic Engineering of Crops: ​ Crops can be genetically engineered for increased resistance to pests and diseases. ​ Potential Downsides: This practice can lead to a loss of genetic diversity within the crop species. Integrated Pest Management: ​ Definition: IPM involves a combination of strategies to manage pest populations effectively while minimizing environmental disruption. ○​ Methods:  ​ Includes biological means (natural predators), physical methods (traps), and limited chemical use (targeted pesticides). ○​ Tactics: ​ Practices such as biocontrol, intercropping, and crop rotation are integral components. Benefits of IPM: ​ Reduces risks associated with pesticide use, protecting wildlife, water supplies, and human health. ​ Aims to sustain pest management in an eco-friendly way. Challenges of IPM: ​ While minimizing environmental disruptions, IPM can be complex and often more expensive to implement compared to conventional methods. Bioaccumulation and Biomagnification ​ Bioaccumulation: ○​ The process through which organisms absorb and concentrate harmful substances, primarily fat-soluble compounds, from their environment. ​ Biomagnification: ○​ The increase in concentration of substances in the tissues of organisms at successively higher trophic levels in a food chain or web. ​ Ecosystem Effects: ○​ Persistent substances can cause issues like eggshell thinning and deformities in top carnivores as they biomagnify through the food chain. ​ Human Health Risks: ○​ Humans can experience adverse health effects such as reproductive, nervous, and circulatory system problems due to biomagnification. ​ Examples of Persistent Substances: ○​ Common substances that bioaccumulate include DDT, mercury, and polychlorinated biphenyls (PCBs), which pose significant environmental concerns. Vocabulary ​ Pesticides: Chemicals used to kill pests. ​ Herbicides: Chemicals specifically designed to kill unwanted plants (weeds). ​ Fungicides: Chemicals that kill fungi, including molds and mildews. ​ Rodenticides: Chemicals that kill rodents. ​ Insecticides: Substances that kill insects. ​ Artificial Selection: The process by which humans breed specific traits in organisms. ​ Genetic Diversity: The variety of genetic characteristics within a species. ​ Biocontrol: Biological method of controlling pests using natural predators or parasites. ​ Intercropping: Growing two or more crops in close proximity for pest control and yield benefits. ​ Crop Rotation: The practice of alternating the types of crops grown in a particular area to improve soil health and reduce pest populations. Meat Production Methods Two Types of Meat Production: Concentrated Animal Feeding Operations (CAFOs): ​ Also known as feedlots. ​ Used to prepare livestock quickly for slaughter. ​ Animals are fed grains rather than their natural diet (grass). ​ Results in overcrowding and significant organic waste production, which can contaminate water supplies. ​ CAFOs are cost-effective, making meat cheaper for consumers. Free-Range Grazing: ​ Animals graze on grass for their entire lifecycle. ​ Typically free from antibiotics and chemicals that are common in feedlots. ​ Organic waste serves as a natural fertilizer. ​ Requires larger land areas and leads to higher prices for consumers. Efficiency of Meat Production: ​ Producing meat is less efficient compared to plant agriculture. ​ Meat production requires approximately 20 times more land to yield the same calorie amount as plants. Environmental Impact of Overgrazing: ​ Results in loss of vegetation and leads to soil erosion. ​ Can cause desertification, where low-precipitation regions become increasingly arid and turn into deserts. Benefits of Reduced Meat Consumption: ​ Can lead to decreased emissions of CO2, methane (CH4), and nitrous oxide (N2O). ​ Helps conserve water resources and reduces the use of antibiotics and growth hormones. ​ Improvement of topsoil quality. Vocabulary: ​ Feedlots: Specific type of CAFO focused on fattening livestock before slaughter. ​ Free-range grazing: Agricultural practice where animals roam freely to graze on grass. ​ Overgrazing: The depletion of vegetation due to excessive feeding by livestock. ​ Desertification: The process through which fertile land becomes increasingly arid and transitions to desert-like conditions. ​ Organic waste: Natural by-products from animals, which can enhance soil fertility. ​ Emissions: Release of gases such as CO2, CH4, and N2O into the atmosphere. Sustainable Agriculture Goal of Soil Conservation: ​ The primary aim is to prevent soil erosion, which can degrade land quality and agricultural productivity. Methods of Soil Conservation: ​ Contour Plowing: ○​ Plowing along the contours of the land to reduce water runoff and soil erosion. ​ Windbreaks: ○​ Planting trees or shrubs to act as barriers against wind, which helps reduce erosion. ​ Perennial Crops: ○​ Crops that live for multiple years, thus minimizing soil disturbance and erosion.  ​ Terracing: ○​ Creating stepped levels on slopes to slow down water runoff and soil loss. ​ No-Till Agriculture: ○​ Practicing farming without plowing to maintain soil structure and reduce erosion. ​ Strip Cropping: ○​ Alternating crops in strips to enhance soil conservation and reduce erosion. Strategies for Soil Fertility Improvement: ​ Crop Rotation: ○​ Alternating different crops in a field to enhance soil nutrients and break pest cycles. ​ Green Manure: ○​ Incorporating cover crops (like legumes) into the soil to improve organic matter and nutrients. ​ Limestone Addition: ○​ Applying limestone to increase soil pH and improve nutrient availability. Rotational Grazing: ​ A practice where livestock is moved between pastures systematically to prevent overgrazing and promote vegetation recovery.