Understanding Cation Exchange Capacity (CEC) in Soil

CEC measures a soil's ability to hold positively charged nutrients (cations) like calcium, magnesium, potassium, and ammonium.

Key Points

• Clay and organic matter have negative charges that attract cations.
• High CEC = more nutrient reserve, less leaching.
• Sandy soils have low CEC; require frequent, light fertilization.
• pH affects CEC: higher pH increases negative charge on organic matter.

Practical Implication

CEC guides fertilizer strategy: high-CEC soils need less frequent applications; low-CEC soils need spoon-feeding. It's a fundamental soil property, not something easily changed.