Compaction Dynamics Over Time

What compaction is

Compaction is the progressive reduction of pore space caused by pressure, settling, and structural collapse.

It affects both soils and substrates.

How compaction develops

• Repeated traffic or handling
• Irrigation-induced settling
• Organic matter decomposition
• Sodium-induced dispersion
• Fine particle migration

Compaction often increases gradually and goes unnoticed.

Effects of compaction

• Increased bulk density
• Reduced air-filled porosity
• Slower drainage
• Restricted root growth
• Reduced oxygen diffusion

Substrates vs soils

• Soils compact mainly from external pressure
• Substrates compact from internal collapse and decomposition
• Lightweight mixes are particularly vulnerable over time

Management strategies

• Avoid working wet soils
• Maintain calcium levels
• Control sodium inputs
• Use structural components in substrates
• Monitor physical properties, not just chemistry

Key concept

Compaction is a time-dependent process, not a single event.