Soil

Components of soil

Sand, silt, clay, nutrients, humus, water, air and organisms

Four reasons of importance

Plants - anchors roots

Water - filters rainwater

Nutrient recycle - home to decomposers

Habitat

Humus

Main organic part of soil (broken down biomass)

Weathering

Breakdown of rocks into smaller pieces

Erosion

Transport of weathered rock fragments by wind and rain

Soil horizons

O-hor. - Layer of organic matter

A-hor. - Topsoil layer of humus

B-hor. - Subsoil layer of minerals

C-hor. - Bedrock, least weathered

3 types of soil degradation

1. Loss of Topsoil: Tilling, loss of vegetation disturbed soil, easier erosion

2. Compaction: Compression by heavy machinery, lessens ability to hold moisture

3. Nutrient depletion: Growing crops on the same soil, removes key nutrients

Parent material

soil pH + nutrient content

Topography

Steep slope = too much erosion

Level ground = deposition

Climate

Warmer = faster breakdown of organic matter

Rainy = more weathering, erosion + deposition

Soil texture

Percentage of sand, silt and clay

Loam

Ideal soil type which balances porosity or drainage with H2O holding cap

Porosity

The amount of pore space (more sandy)

Permeabilty

How easily water drains through a soil

Water holding capacity

How well water is retained by a soil