Soil Properties

Essential Standard 5.00- Explain the role of nutrients and fertilizers.

Objective 5.01

• Discuss Horticulture soils

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

Advantages of horticultural soils

1. Sterile.2. pH is neutral.3. Disease and weed free.4. It is good for starting disease sensitive

seeds• Tomato

5. It is easy to control the nutrient content 6. Improves crop uniformity.7. It is easy to create a horticulture soil for

particular plant needs.

Disadvantages

1. Expensive

2. It is light weight

Carbon : Nitrogen

• Materials with a high carbon to nitrogen ratio– Sawdust– Wood shavings

• Makes nitrogen unavailable for plant use

Soil Profiles and Sampling

Objective 5.02

• Discuss the soil profile and soil sampling 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

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 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

Physical 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

Soil Makeup

Solid particles

Pore Space

Water

Soil Sampling

• Soil sampling and testing is essential for an accurate fertilizer recommendation for growing plants.

Soil Sampling Procedures

1. Create a visual grid of the area to be planted.• For gardens and landscapes, take 5-10 sub-samples • Sample before the growing season.

2. Use a stainless steel soil-sampling probe.3. Take the surface sample to tillage depth

1. about 4inches for lawns2. 6-8 inches for crops

4. Mix the soil samples together.

Soil Sampling Procedures

5. Remove any grass, rocks or other material besides soil.

6. Avoid unusual spots • Problem areas need to be sent in a separate

box.7. Place soil samples in a box

• Obtain from the County Extension Office along with Soil Sample Information sheet

8. Send the box and information to:• Agronomic Division Soil Test Lab in Raleigh

for a free soil test.

FFA Land Judging CDE