Reactions of Lime in Soil
- Reaction with Carbon Dioxide
All liming materials (oxide, hydroxide, or carbonate) react with CO₂ and water in the soil to form bicarbonates:
CaO + H₂O + 2CO₂ → Ca(HCO₃)₂ → Ca²⁺ + 2H₂O + 2CO₂
Ca(OH)₂ + 2CO₂ → Ca(HCO₃)₂ → Ca²⁺ + 2H₂O + 2CO₂
CaCO₃ + H₂O + 2CO₂ → Ca(HCO₃)₂ → Ca²⁺ + 2H₂O + 2CO₂
- Reaction with Soil Colloids
Ca²⁺ and Mg²⁺ from lime replace exchangeable H⁺ and Al³⁺ in the soil, reducing soil acidity.