Chevallier Tiphaine auteur aut IRD Hmaidi K. auteur aut IRD Kouakoua Ernest auteur aut IRD Bernoux Martial auteur aut IRD Gallali T. auteur aut IRD Toucet Joële auteur aut IRD Jolivet C. auteur aut IRD Deleporte P. auteur aut IRD Barthès Bernard auteur aut IRD text journalArticle eng text/pdf born digital access 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. specialized soil organic matter soil respiration carbon stabilization soil structure Q(10) FRANCE TUNISIE 068 178 4 592-600 2015 1436-8730 https://www.documentation.ird.fr/hor/fdi:010064900 10.1002/jpln.201400503 1436-8730 [F B010064900] https://www.documentation.ird.fr/hor/fdi:010064900 https://www.documentation.ird.fr/intranet/publi/2015/09/010064900.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2015-10-07 2023-08-25 fdi:010064900 fre