Soil
Soil quality - based on properties
–Observed: soil profile,
composition, texture, or
particle size
–Measured: pH and
permeability
Soil Profile
• Soil forms in layers - soil profile
–Litter – organic matter on top
–Topsoil- nutrient rich top layer, for
plant growth
–Subsoil- under topsoil, small rocks
–Bedrock- semi solid rock
Soil
Soil
Composition
rock particles, minerals, decayed
material, air & water
• combination of these affects
–type of plants
–type of animals
Texture & particle size
• Texture - size of individual soil
particles.
• Determined by: proportions of sizes
that make up soil
• Particle size range – tiny (clay) to >
2 mm (gravel)
Permeability
• open spaces allowing water to
flow through it.
• How freely water flows is called
permeability.
• Used to understand drainage
• Percolation: amt of seepage
pH
• Soil can be acid-like or base-like
depending on measure of pH
• Soil pH range is 4-10 with lower
numbers being acidic
• Healthy soil is between 5-7
Soil
• MVP = most important abiotic factor in
an ecosystem because everything that
lives on land depends directly or
indirectly
• We lose 7% of topsoil / decade, = more
desert-like conditions.
• As a result of this, Ecosystems are
changing.