Abstract
There were strong correlations between soil pH and pHof water (R2 = 0.810) and total alkalinity (R2 = 0.724) in laboratory soil-water systems prepared with acidic rainwater and pond soil samples from Thailand. Moreover, water pH and total alkalinity were highly correlated (R2 = 0.987). Although soil carbonate concentration was not correlated with total alkalinity, there was a correlation between the product of soil carbonate and soil organic carbon and total alkalinity (R2 = 0.482). Other soil properties, exchange acidity, cation exchange capacity, base saturation, and total sulfur, were either not correlated or weakly correlated with total alkalinity. Total alkalinity did not exceed 20 mg/L except in systems with soils containing free carbonate. A method that estimates the amount of liming material needed to completely base-saturate bottom soils and provides an excess of carbonate, should be used in Thailand and other places. Calcitic agricultural limestone gave higher total alkalinity concentration in soil-water systems than dolomitic agricultural limestone. There usually would be no justification for selecting higher-priced dolomitic limestone for use in ponds.