4 Components of Soil
definitions to know
Porosity: The amount of space between mineral particles within the soil
Water Holding Capacity: The amount of water a soil can absorb
Aeration: The ability for soil to move gas
Weathering: The break down of minerals from the surrounding environement
Essential Nutrients: Nutrients necessary for plant growth and development
Minerals
45%
3 classes of minerals
Sand | Silt | Clay
Mineral class determined by
Color | Texture | Size
Different mixtures of the 3 classes create unique types of soil with different properties.
Smaller particles reduce space between minerals decreasing porosity, and promote better water holding capacity.
Larger particles create more air pockets increasing porosity, and promote better
drainage & aeration.
Organic Matter
5%
Small in quantity, but large impact in soil properties
Four Functions of Organic Matter
​1- Major nutrient source​
2- Food/energy for organisms
3- Stabilize soil structure
4- ​Increase water holding capacity
Organic Matter creates a living, breathing ecosystem where energy and nutrients are exchanged between microbes, plant roots, animals, and water
Decomposed plants and animals broken down by living microbes provide the nutrients and energy to the living system in the soil, completing the circle of life.
Composition of Organic Matter​
Living microbes in the soil like bacteria, fungi, and algae that break down decomposed plants and animals to transfer essential nutrients to mineral particles and plant roots.
Larger organisms like worms and insects loosen the soil to improve aeration and digest decomposing plants and animals to smaller bits and pieces to provide microbes more accessible access to essential nutrients.
Water
25%
Water holding capacity is based on mineral particle size and amount of organic matter
High Organic Matter
Small Particle Size
High Water Holding Capacity
Essential nutrients flow through the water, acting as the highway for nutrients to maneuver
The flow of nutrients in the water is delivered to the plants roots for plant development
Air
25%
The air component is the remaining space between the mineral particles when it is not filled with Organic Matter or Water.
Provides nutrients like Oxygen, Nitrogen, and Carbon (through carbon dioxide) directly into the soil
Loose, porous soil provides better soil aeration and more room for roots to grow.
The air space also allows the soil to soak up excess greenhouse gases in the atmosphere like methane or carbon dioxide.