%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Chevallier, Tiphaine
%A Hmaidi, K.
%A Kouakoua, Ernest
%A Bernoux, Martial
%A Gallali, T.
%A Toucet, Joële
%A Jolivet, C.
%A Deleporte, P.
%A Barthès, Bernard
%T Physical protection of soil carbon in macroaggregates does not reduce the temperature dependence of soil CO2 emissions
%D 2015
%L fdi:010064900
%G ENG
%J Journal of Plant Nutrition and Soil Science
%@ 1436-8730
%K soil organic matter ; soil respiration ; carbon stabilization ; soil structure ; Q(10)
%K FRANCE ; TUNISIE
%M ISI:000359062700007
%N 4
%P 592-600
%R 10.1002/jpln.201400503
%U https://www.documentation.ird.fr/hor/fdi:010064900
%> https://www.documentation.ird.fr/intranet/publi/2015/09/010064900.pdf
%V 178
%W Horizon (IRD)
%X In a warmer world, soil CO2 emissions are likely to increase. There is still much discussion about which soil organic C (SOC) pools are more sensitive to increasing temperatures. While the temperature sensitivity of C stabilized by biochemical recalcitrance or by sorption to mineral surfaces has been characterized, few studies have been carried out on the temperature sensitivityexpressed as Q(10)of C physically protected inside soil macroaggregates (0.2-2mm). It has been suggested that increasing the availability of labile SOC by exposing C through macroaggregate crushing would decrease Q(10), i.e., the temperature dependence of soil CO2 emissions. To test this hypothesis, the temperature dependence of CO2 emissions from C physically protected in macroaggregates was measured through 21-d laboratory incubations of crushed and uncrushed soils, at 18 degrees C and 28 degrees C. 199 topsoil samples, acidic or calcareous, with SOC ranging from 2 to121gkg(-1) soil were investigated. The CO2 emissions were slightly more sensible to temperature than to C deprotection: about 0.3mgCg(-1)soil (=13 mgC g(-1) SOC) and 0.2 mgC g(-1) (=12mgC g(-1) SOC) were additionally mineralized, in average, by increasing the temperature or by disrupting the soil structure, respectively. The mean Q(10) index ratio of CO2 emitted at 28 degrees C and 18 degrees C was similar for crushed and uncrushed soil samples and equaled 1.6. This was partly explained because Q(10) of macro-aggregate-protected C was 1. The results did not support the initial hypothesis of lower temperature dependence of soil CO2 emissions after macroaggregate disruption, although a slight decrease of Q(10) was noticeable after crushing for soils with high amounts of macroaggregate-protected C. Field research is now needed to confirm that soil tillage might have no effect on the temperature sensitivity of SOC stocks.
%$ 068