objective 5.02 discuss the soil profile for surface and subsurface layers
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Objective 5.02
Discuss the soil profile for surface and subsurface layers
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
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 Examples: tobacco farmer, vegetable
gardener Producers of container grown plants add
ingredients to make growing media desirable and are not as concerned with the natural soil’s quality Example: A greenhouse grower uses potting
soil instead of “natural” soil.
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
Which has largest soil particles, Sand or Clay?
SAND
Soil pH
Measurement of acidity or alkalinity from 0 to 14 Acid-less than 0-6.9 Alkaline-more than 8-14
Most organic matter is acid Most artificial media is neutral Ideal pH for most gardens is 5.5 to
7.0
Terms to know aboutPhysical Properties of Soils Permeability
rate at which water moves through the soil
Water holding capacity ability of a soil to hold water for plant
use Porosity
amount of air space between soil particles
Physical Properties of Soils 50% of soil should be pore space
25% water space 25% air space.
50% of soil should be soil particles 45% mineral matter 5% organic matter
WHY DO PLANTS NEED PORE SPACE IN THE SOIL?.......OXYGEN FOR ROOTS!
Soil Makeup
Solid particles
Pore SpaceWater