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One equation to analyse the pH of soil systems
Author(s) -
BOSATTA E.
Publication year - 1993
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1993.tb00453.x
Subject(s) - alkalinity , cation exchange capacity , soil water , chemistry , saturation (graph theory) , soil ph , leaching (pedology) , soil science , inorganic chemistry , context (archaeology) , environmental chemistry , mathematics , environmental science , geology , paleontology , combinatorics
SUMMARY Starting from the basic equations of chemical equilibrium, an analytical mathematical expression is derived that relates pH to base saturation, concentration of acid anions (SO 4 2− , NO 3 − , etc.) and other properties of the soil and soil solution. The equation is particularly valid in acid soils (low base saturation and relatively large, >100 μmol c dm −3 , concentration of acid anions) in the range in which cation exchange is the buffering mechanism. Values of pH, alkalinity and degassed pH calculated with the aid of this equation compared well to values measured in three forest‐floor horizons; calculated pH values also compared well to values measured on a number of acid soils. The equation is also used to derive analytical mathematical expressions for alkalinity, soil leaching sensitivity (a measure of the sensitivity of a soil solution to become dominated by A1 3+ ), and other variables of interest in the context of acidification.