Objective 5.02 Discuss the soil profile for surface and subsurface layers.

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