Horticulture - Soil Pt. 1

Soil

The top layer of the Earth’s surface that generally consists of loose rock, and mineral particles mixed with dead organic matter

Mineral material is derived from

Rock

Soil Properties

Physical, Chemical, and Biological

Physical Soil Property

Color, particle size, porosity, water relations

Chemical Soil Property

Nutrient holding ability, soil acidity (pH)

Biological Soil Property

Soil microflora, macrofauna, partnerships

• Up to 1 billion bacteria - mostly beneficial to soil and plants

• Soil Fungi - responsible for progressive activity in soil

Is soil alive?

No

What should good soil do?

Provide:

• Anchorage

• Water - Cohesive (stick together) and Adhesive (stick onto things)

• Nutrients

• Oxygen - roots don’t grow if there is no oxygen

What should good soil do? Pt. 2

• Improve water infiltration by up to 20%

• Reduce and slows runoff (sedimentation)

• Purifies water - takes impurities out

• Decomposes pollutants

• Bacteria - Microbacterium vaccae promotes human health

• Reduce irrigation and fertilizing frequency

• Increases plant longevity

How does bacteria Microbacterium vaccae promotes human health?

Secretes serotonin when inhaled/ingested

Ideal Soil Makeup

Mineral particles - 45%

Water - 25%

Air - 25%

Organic Matter - 5%

• Humus - 80%

• Roots - 10%

• Organisms - 10%

Soil Profile: Horizonation

• Surface Layers

• Topsoil

• Subsoil

• Loose Parent Material

• Bedrock

Surface Layers

Organic debris, partly decomposed (O horizons)

Topsoil

Mineral particles mixed with organic material (A horizons)

Subsoil

Compounds draining from above accumulates (B Horizons)

• Generally a lighter soil color

Loose Parent Material

Partly weathered rock (C Horizons)

Bedrock

R horizons

How to take a soil profile?

Use a soil probe