APES Unit 3 - Agricultural system

Biogeochemical Cycle

The natural cycling of matter between living and non-living parts of ecosystems.

Reservoir

A storage area for elements or compounds, such as carbon in the atmosphere or nitrogen in soil.

Sequestration

The long-term storage of carbon or other elements in natural sinks like oceans or forests.

Ecosystem Services

Benefits provided by natural ecosystems, including water purification, pollination, and carbon sequestration.

Limiting Factor

A resource that is scarce but vital to ecosystem function, such as nitrogen or phosphorus.

Carbon Cycle

The movement of carbon between sources and sinks through biological and geological processes.

Photosynthesis

The process by which plants convert CO₂ and sunlight into glucose and oxygen.

Cellular Respiration

The process of breaking down glucose for energy, releasing CO₂.

Fast Carbon Cycling

The movement of carbon through biological processes such as photosynthesis and respiration.

Sedimentation & Burial

Long-term carbon storage in ocean sediments and fossil fuels.

Combustion

The burning of fossil fuels, releasing CO₂ into the atmosphere.

Uplift & Weathering

The release of stored carbon through geological processes.

Nitrogen Cycle

The movement of nitrogen through biological and geological processes.

Nitrogen Fixation

The conversion of atmospheric nitrogen (N₂) into a form usable by plants (NH₃, NH₄⁺).

Ammonification

The process by which decomposers convert organic nitrogen into ammonia (NH₃).

Nitrification

The conversion of ammonia (NH₄⁺) into nitrites (NO₂⁻) and then nitrates (NO₃⁻).

Assimilation

The uptake of nitrogen by plants to form amino acids and DNA.

Denitrification

The conversion of nitrates (NO₃⁻) back into atmospheric nitrogen (N₂) by bacteria.

Phosphorus Cycle

The movement of phosphorus through land, water, and organisms without an atmospheric component.

Weathering & Erosion

The breakdown of rocks releasing phosphorus into the soil and water.

Runoff

The movement of phosphorus from land to aquatic ecosystems.

Sedimentation

The formation of new rocks from accumulated phosphorus over time.

Eutrophication

Excess phosphorus (or nitrogen) in water leading to algal blooms and hypoxia.

Hydrologic Cycle

The movement of water through evaporation, condensation, precipitation, and infiltration.

Evaporation

The transformation of water from liquid to gas.

Condensation

The formation of clouds as water vapor cools.

Precipitation

Water falling to Earth as rain, snow, sleet, or hail.

Infiltration

Water seeping into the ground to replenish groundwater.

Green Revolution

The shift to modern agricultural techniques including mechanization, irrigation, GMOs, and chemical fertilizers.

Monoculture

The practice of growing a single crop species over a large area, reducing biodiversity.

GMO (Genetically Modified Organism)

An organism whose genetic material has been altered for desired traits.

Artificial Selection

The process of breeding organisms to enhance specific traits.

Pesticide Treadmill

The cycle of pest resistance requiring stronger pesticide applications.

Slash-and-Burn Agriculture

The cutting and burning of forests to create farmland.

Tilling

The process of turning soil before planting, which increases erosion and CO₂ release.

Overgrazing

When livestock consume vegetation faster than it can regenerate, leading to desertification.

Soil Compaction

When heavy machinery or livestock press soil particles together, reducing water infiltration.

Crop Rotation

Alternating crops each season to maintain soil nutrients and reduce pests.

Intercropping

Planting different crops together to improve soil health and biodiversity.

CAFOs (Concentrated Animal Feeding Operations)

Industrialized farming systems with high-density livestock.

Methane Emissions

Greenhouse gas released by cattle digestion.

Antibiotic Resistance

The evolution of bacteria due to excessive antibiotic use in livestock.

Tragedy of the Commons

Overuse of shared resources leading to depletion (e.g., overgrazing).

Free-Range Grazing

Livestock raised with natural grazing practices, requiring more land.

Soil Horizons

Different layers of soil, including topsoil (O & A horizons), subsoil (B horizon), and bedrock.

Erosion

The removal of soil by wind or water.

Desertification

The transformation of fertile land into desert due to overgrazing and deforestation.

Loam

A balanced mixture of sand, silt, and clay ideal for plant growth.

Percolation

The movement of water through soil.

Infiltration

The process of water soaking into the ground.

Windbreaks

Rows of trees planted to reduce wind erosion.

Contour Plowing

Plowing along land contours to reduce erosion.

Terracing

Step-like ridges built on slopes to prevent erosion.

No-Till Agriculture

Farming without disturbing soil structure, reducing erosion.

Furrow Irrigation

Water is poured into trenches between crop rows.

Flood Irrigation

Entire fields are flooded with water, leading to high evaporation losses.

Spray Irrigation

Water is sprayed over crops, more efficient but energy-intensive.

Drip Irrigation

A system that delivers water directly to plant roots, minimizing waste.

Salinization

The accumulation of salts in soil due to irrigation.

Waterlogging

Excess water saturation in soil, suffocating plant roots.

Aquifers

Underground water reservoirs.

Ogallala Aquifer

A major freshwater source in the U.S. Great Plains.

Point Source Pollution

Pollution from a single, identifiable source (e.g., factory discharge).

Nonpoint Source Pollution

Diffuse pollution from multiple sources (e.g., agricultural runoff).

Hypoxia (Dead Zones)

Areas in water with too little oxygen to support marine life.

Thermal Pollution

When industries discharge heated water into natural water bodies, disrupting ecosystems.

Noise Pollution

Harmful underwater noise from ships, sonar, and oil exploration.

Bioaccumulation

The buildup of toxins in an organism over time.

Biomagnification

The increasing concentration of toxins as they move up the food chain.

Endocrine Disruptors

Chemicals that interfere with hormonal systems (e.g., atrazine, DDT).

Heavy Metals

Toxic metals like lead, mercury, and arsenic that accumulate in organisms.

Persistent Organic Pollutants (POPs)

Toxic chemicals that remain in the environment for long periods.

10% Rule

The concept that only 10% of energy is transferred between trophic levels in a food chain.

Carbon Footprint

The total greenhouse gas emissions caused by an individual, organization, or country.

Albedo Effect

The ability of surfaces to reflect sunlight; lower albedo leads to higher heat absorption.

What process in the nitrogen cycle converts atmospheric nitrogen (N₂) into a usable form for plants?

Nitrogen Fixation

Describe one way human activity disrupts the phosphorus cycle.

Excess phosphorus from fertilizers runs off into water bodies, causing eutrophication and algal blooms.

A farmer notices that after years of growing the same crop, the soil is less fertile. What sustainable farming technique could improve soil quality without synthetic fertilizers?

Crop Rotation - growing different crops in alternating seasons replenishes soil nutrients naturally.

Why is the phosphorus cycle considered slower than the carbon or nitrogen cycles?

Phosphorus does not have a gaseous phase; it moves primarily through rock weathering and sedimentation.

A pesticide is applied to a crop, but over time, it becomes less effective, requiring stronger applications. What is this phenomenon called?

Pesticide Treadmill

What is the largest reservoir of carbon in the carbon cycle?

The ocean

What type of irrigation is the most water-efficient but also the most expensive?

Drip Irrigation

How does deforestation contribute to increased atmospheric CO₂?

Trees store carbon; removing them releases CO₂ and reduces future carbon sequestration.

What greenhouse gas is released in large amounts by cattle digestion?

Methane (CH₄)

What agricultural method involves clearing land by cutting and burning vegetation?

Slash-and-Burn Agriculture

What process in the water cycle moves water from the ground into the atmosphere?

Evaporation

Why are GMOs controversial?

Concerns include loss of genetic diversity, patent issues, and potential unknown health effects.

What is the process by which pollutants increase in concentration as they move up the food chain?

Biomagnification

What type of pollution results from increased water temperature due to industrial activities?

Thermal Pollution

What is a major consequence of eutrophication in aquatic ecosystems?

Hypoxia (low oxygen levels), leading to dead zones.

What is the 10% rule in energy transfer?

Only 10% of energy is passed to the next trophic level; the rest is lost as heat.

What type of soil particle holds the most water?

Clay

What is the primary cause of desertification?

Overgrazing, deforestation, and poor agricultural practices.

What soil conservation technique involves plowing along natural land contours to prevent erosion?

Contour Plowing

What law requires industries to obtain a permit before releasing pollutants into U.S. waterways?

The Clean Water Act

What process moves water downward into the soil to replenish groundwater?

Infiltration

What type of farming avoids synthetic fertilizers and pesticides?

Organic Farming

How do concentrated animal feeding operations (CAFOs) contribute to water pollution?

Animal waste runoff contaminates water with nutrients and pathogens.

What causes the formation of hypoxic dead zones in coastal areas?

Excess nutrients (especially nitrogen and phosphorus) from agricultural runoff.

What environmental problem occurs when aquifers are overused faster than they can recharge?

Groundwater Depletion