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Mean residence time of soil organic matter associated with kaolinite and smectite
Author(s) -
Wattel Koekkoek E. J. W.,
Buurman P.,
Van Der Plicht J.,
Wattel E.,
Van Breemen N.
Publication year - 2003
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1046/j.1365-2389.2003.00512.x
Subject(s) - kaolinite , organic matter , clay minerals , soil water , soil science , soil organic matter , total organic carbon , residence time (fluid dynamics) , mineralogy , environmental chemistry , chemistry , environmental science , geology , geotechnical engineering , organic chemistry
Summary To gain insight into the effect of clay mineralogy on the turnover of organic matter, we analysed the 14 C activity of soil organic matter associated with clay in soils dominated by kaolinite and smectite in natural savanna systems in seven countries. Assuming that carbon inputs and outputs are in equilibrium in such soils, we took the 14 C age as mean residence time of the organic matter. We corrected the 14 C activity for the Suess effect, Bomb effect and difference between date of sampling and date of 14 C measurement. Organic matter associated with kaolinite turned over fast (360 years on average). Organic matter associated with smectite turned over relatively slowly, with an average mean residence time for the whole clay‐size fraction of 1100 years. Multiple linear regression indicates that clay mineralogy is the main factor explaining differences in the mean residence time of the organic matter extracted.