Dynamics and identification of soil microbial populations actively assimilating carbon from 13C-labelled wheat residue as estimated by DNA- and RNA-SIP techniques.

International audience; This work is the first report on the use of DNA-, RNA-SIP approaches to elucidate the dynamics and the diversity of bacterial populations actively assimilating C derived from plant residues labelled at more than 90% (13)C. Wheat-residues, were incorporated and incubated into soil microcosms for 28 days. At the end of the incubation time, no more than 55% of the total CO(2) released was (13)C-labelled, suggesting the occurrence of an important priming effect process. After 7 days, more than 30% of the whole DNA extracted were labelled, allowing an efficient separation of labelled from unlabelled DNA using density gradient centrifugation. The genetic structure of bacte…

Conclusion générale

Soil Organic Matter in Mediterranean regions

Contamination of soil by copper affects the dynamics, diversity, and activity of soil bacterial communities involved in wheat decomposition and carbon storage.

ABSTRACT A soil microcosm experiment was conducted to evaluate the influence of copper contamination on the dynamics and diversity of bacterial communities actively involved in wheat residue decomposition. In the presence of copper, a higher level of CO 2 release was observed, which did not arise from greater wheat decomposition but from a higher level of stimulation of soil organic matter mineralization (known as the priming effect). Such functional modifications may be related to significant modifications in the diversity of active bacterial populations characterized using the DNA stable-isotope probing approach.

Le potentiel de stockage de carbone du semis direct en comparaison d'autres techniques culturales

International audience