Soil composition
Solid phase (minerals + organic matter), liquid phase (soil water), gas phase (soil air). Humus comes from organic matter decomposition.
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Lesson overview
This lesson brings together the PDF, study notes and chapter flow so you can revise Edaphic Factors without losing the thread.
Soil composition
Solid phase (minerals + organic matter), liquid phase (soil water), gas phase (soil air). Humus comes from organic matter decomposition.
Soil pH
Measures acidity or basicity. pH 7 = neutral, pH < 7 = acidic, pH > 7 = basic. Influences nutrient uptake.
Texture and structure
Texture = proportions of sand, silt, clay. Structure = particle arrangement. Determines permeability and water retention.
Organic matter and humus
Litter (dead leaves…) is decomposed by decomposers (bacteria, fungi) into humus that enriches the soil.
Observation 1 - Edaphic Factors
Microscopic analysis.
Observation 2 - Edaphic Factors
Microscopic analysis.
Observation 3 - Edaphic Factors
Microscopic analysis.
Observation 4 - Edaphic Factors
Microscopic analysis.
Observation 5 - Edaphic Factors
Microscopic analysis.
Diagram 1 - Edaphic Factors
Diagram description.
Diagram 2 - Edaphic Factors
Diagram description.
Diagram 3 - Edaphic Factors
Diagram description.
Diagram 4 - Edaphic Factors
Diagram description.
Diagram 5 - Edaphic Factors
Diagram description.
Experiment 1 - Edaphic Factors
Results interpretation.
Experiment 2 - Edaphic Factors
Results interpretation.
Experiment 3 - Edaphic Factors
Results interpretation.
Experiment 4 - Edaphic Factors
Results interpretation.
Experiment 5 - Edaphic Factors
Results interpretation.
Observe → describe → explain
Start from facts (document/experiment), then build a reasoned scientific explanation.
Precise scientific vocabulary
Use exact terms: ecological factor, valence, productivity, biotope, biocenosis, reproduction.
Limiting factor
Growth/activity depends on the most constraining environmental factor.
Ecological valence
Wide valence = euryecious species; narrow valence = stenoecious species.