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A bicarbonate titration method for lime requirement to neutralize exchangeable acidity of pond bottom soils
- Han, Yangxue, Boyd, Claude E., Viriyatum, Rawee
- Aquaculture 2014 v.434 pp. 282-287
- acidity, alkalinity, bicarbonates, calcium carbonate, lime requirement, neutralization, pH, ponds, potassium, soil, soil sampling, sulfuric acid, titration
- The lime requirement of ponds can be determined by direct titration with standard sulfuric acid of the amount of alkalinity neutralized by the exchangeable acidity displaced from a bottom soil sample equilibrated with a solution of 1.0N in potassium ion and 0.04N in bicarbonate (2mg CaCO3 equivalent mL−1). This procedure, called the K-bicarbonate method here, provided precise estimates of lime requirement that were 9.6% to 27.2% (average=12.9%) greater than those obtained by the method currently recommended for use on pond soils. It is likely that the K-bicarbonate method neutralizes more of the exchangeable acidity in pond bottom soil samples than does the current method recommended for pond bottom soils and thereby provides a more reliable estimate of lime requirement. Moreover, the K-bicarbonate method does not require a hazardous chemical, a mechanical shaker, or a pH meter as does the current method for pond lime requirement. The cost per analysis also is cheaper by the K-bicarbonate method than with the method currently recommended for pond soils.