Neto M. S. auteur aut IRD Scopel E. auteur aut IRD Corbeels M. auteur aut IRD Cardoso A. N. auteur aut IRD Douzet J. M. auteur aut IRD Feller Christian auteur aut IRD Piccolo M. D. auteur aut IRD Cerri C. C. auteur aut IRD Bernoux Martial auteur aut IRD text journalArticle eng text/pdf born digital access No-tillage mulch-based (NTM) cropping systems have been widely adopted by farmers in the Brazilian savanna region (Cerrado biome). We hypothesized that this new type of management should have a profound impact on soil organic carbon (SOC) at regional scale and consequently on climate change mitigation. The objective of this study was thus to quantify the SOC storage potential of NTM in the oxisols of the Cerrado using a synchronic approach that is based on a chronosequence of fields of different years under NTM. The study consisted of three phases: (1) a farm/cropping system survey to identify the main types of NTM systems to be chosen for the chronosequence; (2) a field survey to identify a homogeneous set of situations for the chronosequence and (3) the characterization of the chronosequence to assess the SOC storage potential. The main NTM system practiced by farmers is an annual succession of soybean (Glycine max)or maize (Zea mays) with another cereal crop. This cropping system covers 54% of the total cultivated area in the region. At the regional level, soil organic C concentrations from NTM fields were closely correlated with clay + silt content of the soil (r(2) = 0.64). No significant correlation was observed (r(2) = 0.07), however, between these two variables when we only considered the fields with a clay + silt content in the 500-700 g kg(-1) range. The final chronosequence of NTM fields was therefore based on a subsample of eight fields, within this textural range. The SOC stocks in the 0-30 cm topsoil layer of these selected fields varied between 4.2 and 6.7 kg C m(-2) and increased on average (r(2) = 0.97) with 0.19 kg C m(-2) year(-1). After 12 years of NTM management, SOC stocks were no longer significantly different from the stocks under natural Cerrado vegetation (p < 0.05), whereas a 23-year-old conventionally tilled and cropped field showed SOC stocks that were about 30% below this level. Confirming our hypotheses, this study clearly illustrated the high potential of NTM systems in increasing SOC storage under tropical conditions, and how a synchronic approach may be used to assess efficiently such modification on farmers' fields, identifying and excluding non desirable sources of heterogeneity (management, soils and climate). specialized Cover crops Chronosequence Intensive agriculture Tropics Oxisols 068 110 1 187-195 2010 0167-1987 https://www.documentation.ird.fr/hor/fdi:010049063 10.1016/j.still.2010.07.010 0167-1987 [F B010049063] https://www.documentation.ird.fr/hor/fdi:010049063 https://www.documentation.ird.fr/intranet/publi/2010/10/010049063.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2010-11-05 2017-08-23 fdi:010049063 fre