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A Double Buffer Method for the Determination of Lime Requirement of Acid Soils
Author(s) -
Yuan T. L.
Publication year - 1974
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1974.03615995003800030020x
Subject(s) - lime , soil ph , chemistry , triethanolamine , soil water , titration , buffer solution , cation exchange capacity , buffer (optical fiber) , soil test , soil acidification , titration curve , inorganic chemistry , environmental chemistry , chromatography , soil science , analytical chemistry (journal) , geology , paleontology , telecommunications , computer science
A buffer method to take into consideration both the acidity and buffering property of individual acid soils was investigated. The buffer was composed of tris, imidazol, chromate, and pyridine in a 0.2 M CaCl 2 solution. It was prepared so that each addition of 0.1 meq of a strong acid to 50 ml of this buffer would reduce the pH by 0.1 unit within the pH range of 8.0 and 5.4. Two buffers of the same composition, one adjusted to pH 7.00 and the other to pH 6.00, were added to two separate soil samples. After shaking for 1 hour the pH was determined. The depression of the buffer pH measured the soil acidity neutralized to the equilibrium pH in these systems. The soil acidity to be neutralized from the equilibrium pH to the desired pH was determined by the buffering property of soil which, in turn, was defined by dividing the difference in soil acidity neutralized in the two buffer systems by the difference of the two equilibrium pH values. This is to represent the acidity released by the soil at each increment of pH. The lime required to raise the soil to the desired pH was calculated from the sum of these two acidity portions. The results from this method were highly correlated with and comparable to those by the lime incubation and BaCl 2 ‐triethanolamine methods.