review packet

Tectonic Plate Boundaries & Examples

  • Divergent: Mid-Atlantic Ridge (Iceland), Great Rift Valley (Africa)

  • Transform: San Andreas Fault (California), Turkey

  • Convergent: Himalayas, Japan, Caribbean Islands, Andes Mountains, Cascades (Washington State)

Soil-Related Topics

  • Weathering: Breakdown of rocks into soil

  • Soil Composition: Minerals, organic material, water, air

  • Soil Layers: The top three layers (excluding eluviated) are the most important. The most productive layer is topsoil because it contains the highest amount of organic matter.

  • Ecosystem Services of Soil:

    1. Nutrient cycling

    2. Water filtration

Physical Properties of Soil

  • Texture: Determined by particle size

  • Permeability: Rate at which water moves through soil

  • Porosity: Space between soil particles

Chemical Properties of Soil

  • Nutrients: Essential elements like nitrogen, phosphorus, and potassium

  • CEC (Cation Exchange Capacity): High in clay, good for nutrient retention

  • pH: Affects nutrient availability; slightly higher pH is generally better

  • Salinity: Excess salts can harm plant growth

Biological Properties of Soil

  • Functions of Soil Organisms: Decomposition, nutrient cycling, soil aeration

  • Best Type of Soil: Loam (balance of sand, silt, and clay)

Human Impact on Soil

  • Soil Degradation:

    • Overgrazing

    • Deforestation

    • Poor agricultural practices

Tragedy of the Commons

  • Example: Overfishing

  • Solutions: Regulations, ownership policies

Industrial Agriculture (Green Revolution)

  • Practices:

    • Monocropping

    • High-yield crop varieties

    • Synthetic fertilizers and pesticides

Pesticide Treadmill: Pests develop resistance, requiring stronger chemicals Antibiotic Resistance: Similar to the pesticide treadmill, but with bacteria

Irrigation Issues

  • Waterlogging

  • Salinization

  • Aquifer depletion

  • Saltwater intrusion

Sustainable Agriculture Techniques

  • Contour Plowing: Reduces soil erosion

  • Windbreaks: Prevent wind erosion

  • Perennials: Reduce soil disturbance

  • Terracing: Prevents water runoff

  • No-Till Farming: Reduces soil degradation

  • Crop Rotation: Prevents nutrient depletion

  • Green Manure: Adds nutrients back into soil

  • Rotational Grazing: Prevents overgrazing

Environmental Consequences of Modern Agriculture

  • Climate change

  • Soil degradation

  • Water scarcity

  • Biodiversity loss

Steps to Feeding the World Sustainably

  • Reduce food waste

  • Improve crop efficiency

  • Use resources efficiently

  • Promote regenerative agriculture