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Higher temperature sensitivity for stable than for labile soil organic carbon – Evidence from incubations of long‐term bare fallow soils
Author(s) -
Lefèvre Romain,
Barré Pierre,
Moyano Fernando E.,
Christensen Bent T.,
Bardoux Gérard,
Eglin Thomas,
Girardin Cyril,
Houot Sabine,
Kätterer Thomas,
Oort Folkert,
Chenu Claire
Publication year - 2014
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.12402
Subject(s) - soil water , environmental chemistry , environmental science , soil carbon , term (time) , carbon fibers , soil science , soil organic matter , carbon cycle , chemistry , ecology , ecosystem , materials science , biology , physics , quantum mechanics , composite number , composite material
The impact of climate change on the stability of soil organic carbon ( SOC ) remains a major source of uncertainty in predicting future changes in atmospheric CO 2 levels. One unsettled issue is whether the mineralization response to temperature depends on SOC mineralization rate. Long‐term (>25 years) bare fallow experiments ( LTBF ) in which the soil is kept free of any vegetation and organic inputs, and their associated archives of soil samples represent a unique research platform to examine this issue as with increasing duration of fallow, the lability of remaining total SOC decreases. We retrieved soils from LTBF experiments situated at Askov (Denmark), Grignon (France), Ultuna (Sweden), and Versailles (France) and sampled at the start of the experiments and after 25, 50, 52, and 79 years of bare fallow, respectively. Soils were incubated at 4, 12, 20, and 35 °C and the evolved CO 2 monitored. The apparent activation energy ( E a ) of SOC was then calculated for similar loss of CO 2 at the different temperatures. The E a was always higher for samples taken at the end of the bare‐fallow period, implying a higher temperature sensitivity of stable C than of labile C . Our results provide strong evidence for a general relationship between temperature sensitivity and SOC stability upon which significant improvements in predictive models could be based.