Oxygen Demand vs Temperature

Core concept

Root respiration is temperature-dependent. As temperature rises, roots consume oxygen faster.

This means oxygen stress can occur even when air-filled porosity appears adequate.

Temperature effects

• Respiration roughly doubles for every 10°C increase
• Oxygen solubility in water decreases as temperature rises
• Warm, wet root zones are the highest risk combination

Practical implications

• Summer irrigation carries higher oxygen risk
• Warm substrates require higher AFP
• High EC compounds oxygen stress
• Root pathogens thrive under low-oxygen, warm conditions

Agronomic note

Many “summer nutrient problems” are actually oxygen demand problems, not feed rate issues.