@article{fdi:010086318,
  title = {{D}rivers of the amount of organic carbon protected inside soil aggregates estimated by crushing : a meta-analysis},
  author = {{K}pemoua, {T}. {P}. {I}. and {B}arre, {P}. and {C}hevallier, {T}iphaine and {H}ouot, {S}. and {C}henu, {C}.},
  editor = {},
  language = {{ENG}},
  abstract = {{G}iven the importance of soil organic carbon ({SOC}) stocks and their dynamics in the regulation of climate change, understanding the mechanisms of {SOC} protection from decomposition is crucial. {I}t is recognized that soil aggregates can provide effective protection of organic carbon from microbial decomposition. {C}urrently, there is no systematic method for estimating the amount of protected carbon within aggregates. {H}owever, differences between {CO}2 emissions from incubation of intact versus crushed aggregates have been widely used as a proxy for {SOC} physical protection within aggregates. {T}here is no global analysis on this type of experiment yet, nor on the drivers of the amount of {SOC} physically protected in soils. {U}sing a meta-analysis including 165 pairs of observations from 22 studies encompassing a variety of ecosystems, climate and soil types, we investigated the crushing effects on cumulative carbon mineralization from laboratory incubation experiments. {T}he aggregates were initially separated by either wet sieving or dry sieving before dry crushing. {O}ur results indicated that aggregate crushing led on average to +31 % stimulation of carbon mineralization compared with intact aggregates, which represented 0.65 to 1.01 % of total {SOC}. {T}his result suggests the mineralization of a previously protected pool of labile organic carbon. {T}he linear regression analysis showed that the crushing effect on carbon mineralization depended on soil characteristics (carbon content, clay content and p{H}) as well as on aggregate size. {C}rushing aggregates stimulated carbon mineralization relative to control, up to +63 % in large aggregates (>10 mm), +38 % in large macro-aggregates (2-8 mm), +14 % in small macro-aggregates (0.25-2 mm) and +54 % in micro-aggregates (<0.25 mm). {W}ithin each aggregate size-class, the crushing effect depended on the crushing intensity. {T}he destruction of aggregates to <0.05 mm size had a greater effect on carbon mineralization (+130-133 %) than the destruction of aggregates to >2 mm (+3 to 40 %), < 2 mm (+58 to 62 %) and < 0.25 mm (+32 to 62 %) sizes regardless of the initial aggregate size. {T}hese results suggest that macroaggregates (>0.25 mm) are less protective than microaggregates (<0.25 mm). {O}ur dataset also show that soil physicochemical characteristics and experimental conditions influenced more the amount of protected {SOC} than land use and management. {C}ontrary to our expectations the crushing effect was not affected by tillage practices nor land use. {S}tandardizing the experimental conditions of aggregate crushing and subsequent incubation is needed to assess and compare the amount of physically protected {SOC} in diverse soils, and then to better understand the processes and drivers of {SOC} protection inside aggregates.},
  keywords = {{O}rganic carbon ; {A}ggregates ; {P}hysical protection ; {C}rushing ; {C}arbon mineralization},
  booktitle = {},
  journal = {{G}eoderma},
  volume = {427},
  numero = {},
  pages = {116089 [15 p.]},
  ISSN = {0016-7061},
  year = {2022},
  DOI = {10.1016/j.geoderma.2022.116089},
  URL = {https://www.documentation.ird.fr/hor/fdi:010086318},
}