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A Dual‐Buffer Titration Method for Lime Requirement of Acid Minesoils
Author(s) -
Harper W. S.,
Baker D. E.,
McCormick L. H.
Publication year - 1988
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1988.00472425001700030018x
Subject(s) - titration , lime , chemistry , acid–base titration , soil ph , hydrolysis , buffer (optical fiber) , soil water , stoichiometry , soil test , base (topology) , inorganic chemistry , soil science , organic chemistry , environmental science , mathematics , materials science , metallurgy , telecommunications , mathematical analysis , computer science
A lime requirement test termed the dual‐buffer titration (DBT) was developed for acid minesoils occurring in Pennsylvania. The DBT uses two buffers to stoichiometrically account for contributions of hydrogen ions (H + ) to soil acidity to pH 7.0, including those from the hydrolysis of Al. The first buffer lowers the soil pH to 3.17 to dissolve Al‐OH polymers, amorphous coatings, and interlayer species. The second buffer raises the pH to approximately 8.2, titrating the exchangeable Al 3+ and other hydrolyzed species to neutralized forms. Lastly, a titration of the buffers‐soil mixture with standardized base to pH 8.2 provides a direct measure of the lime requirement. For comparison, a 5‐month CaCO 3 incubation of 31 soils was also determined. The results by the two methods were highly correlated ( r = 0.92) for 24 samples and statistically the same at a probability level of 0.001.