Soil Properties

23.00-Explain the properties of soils and their relationship

to plant growth.

Soils and growing media

• Soils and growing media are made up of two types of materials– Organic matter– Inorganic compounds

Organic Matter

• Dead plant or animal tissue

• contains carbon

• usually has diseases or insects

Types of organic matter

• Compost

• bark-particles too large to use in seed germination media

• mulch-used to cover soil to help hold moisture and prevent weeds

• straw

• peat moss

Composting

Types of Organic Matter

• Sphagnum

• Sawdust-high carbon to nitrogen ratio makes nitrogen unavailable for plant use

• Wood shavings- high carbon to nitrogen ratio makes nitrogen unavailable for plant use

Inorganic compounds

• Do not contain carbon

• usually sterile

Types of inorganic compounds

• Soilless media-artificial soil

• Vermiculite-mica mineral matter used to start seeds and cuttings, helps hold moisture, has neutral pH

• Perlite-natural volcanic material that helps aeration and water-holding capacity

Vermiculite

Perlite

pH• Measurement of acidity or alkalinity

from 0 to 14• Acid-less than 7.0• Alkaline-more than 7.0• Most organic matter is acid• Most artificial media is neutral• Ideal pH for most ornamental plants

and lawn or turf grasses is 5.5 to 7.0

Hydroponics

• The process of growing plants without soil

Types of hydroponics

• Aggregate culture– using sand or gravel to support plant

roots

• Water culture, solution culture, or nutriculture– plant roots grow in water containing

dissolved nutrients

Types of hydroponics

• Aeroponics– plant roots hang in air and are misted

regularly with a nutrient solution

• Continuous-flow system– nutrient solution flows constantly

over plant roots–most commonly used for commercial

production

Hydroponics at Epcot

Advantages of hydroponics

• No soil and problems associated with soil

• Easy to control nutrient content of plants

Disadvantages of hydroponics

• Plant support must be provided with strings, wires or stakes

• Water quality must be high• Diseases spread through water• More moisture or humidity in air to

cause favorable environment for disease organisms

• More expensive

What is the physical make up of soil?

Soil Profile

• Layers of soil are called horizons

• Typical profile– A Horizon-topsoil• most fertile• most organic matter• top or first layer

– B Horizon-subsoil– C Horizon-bedrock

Soil Profile

A Horizon

B Horizon

C Horizon

Soil Profile

Soil Structure

• How particles cluster together– single grain– granular (best for most plants)– blocky– platy–massive

Soil Structure

Single Grain

Soil Structure

Granular

Soil Structure

Blocky

Soil Structure

Platy

Soil Structure

Massive

Soil structure

• Soil structure is more important to producers who grow plants in natural soils

• Producers of container grown plants add ingredients to make growing media desirable

Soil Texture

• Size of particles

• Types of textures– clayey– loamy– sandy

Clayey Texture

• Small particles

• Has a high water-holding capacity

• most common texture in western NC

Loamy texture

• About equal parts of sand, clay and silt

• Ideal texture for most non-container outside plants

Sandy texture

• Large particles

• Low moisture-holding capacity

• Most common in eastern NC

Soil Makeup

Solid particles

Pore Space

Water

FFA Land Judging CDE