Indicators of Soil Quality

• Due to weathering and erosion, the Sedimentary, Metamorphic Igneous Rocks are turning into sediment.
• Due to heat and pressure, the Sedimentary and Igneous Rocks are turning into Metamorphic Rocks.
• Due to compaction and cementation, the sediment turns into Sedimentary Rocks.
• Due to melting through the atmosphere, the Igneous and Metamorphic Rocks turn into magma.
• Due to cooling, the magma forms back into Igneous Rocks.
• What is the Weathering process?


  > breaking down or dissolving of rocks and minerals on Earth's surface.
• What are the factors that can affect the Weathering process?

  > temperature and climate

  > Moisture or water

  > Type of rocks
• Mechanical Weathering - breaking or disintegration of rocks into smaller pieces without changing their composition.

  CAUSES:

  * Ice wedging

  * pressure release

  * plant growth

  * abrasion
• Biological Weathering - It is contributed to or removal of ions and minerals from the weathering environment and physical variations due to movement or development of organisms.

  CAUSES: plants, animals, fungi, bacteria.
• Soil - surface material that covers most land. It contains mineral particles, organic matter, water, and air.
• Composition of Soil:

  Water - 25%

  Air - 25%

  Mineral - 45%

  Organic Matter - 5%
• WHAT ARE THE SOIL PROPERTIES?

  Texture - size of particles; proportion of its composition (sand, silt, clay & loam)

  IMPORTANCE:

  * aeration

  * water drainage/retention

  * useful in agriculture.
• Structure - arrangement of its composition; influence by the presence of organic matter & other organisms.

  IMPORTANCE:

  * aeration

  * water movement

  * useful for plant growth.
• Porosity - This is the amount of pore space between soil particles.
• Chemistry - chemical composition, properties & reaction of soils.

  IMPORTANCE: nutrients absorption.
• Color - indicates the presence or amount of organic matter and iron.

  IMPORTANCE: water drainage.
• Profile - shows the different layers/section/horizon.

  IMPORTANCE: nutrients content/quality.
• HORIZONS IN SOIL PROFILE:

  O (Organic) - rich in humus

  A (Surface) - known as topsoil

  B (subsoil) - rich in minerals

  C (Substratum) - partially weathered rocks

  R (Bedrock) - mass of rock.
• Chemical weathering is a process where rocks and other materials are broken down by chemical reactions, primarily through the interaction with water and dissolved chemicals.