Résumé
Soil microorganisms are responsible for organic matter decomposition processes that regulate soil carbon storage and mineralisation to CO2. Climate change is predicted to increase the frequency of drought events, with uncertain consequences for soil microbial communities. In this study we tested the hypothesis that agricultural management used to enhance soil carbon stocks would increase the stability of microbial community structure and activity in response to water-stress. Soil was sampled from a long-term field trial with three soil carbon management systems and was used in a laboratory study of the effect of a dry–wet cycle on organic C mineralisation and microbial community structure. After a drying–rewetting event, soil microcosms were maintained wet and microbial community structure and abundance as well as microbial respiration were measured for four weeks. The results showed that the NO-TILL management system, with the highest soil organic matter content and respiration rate, had a distinct bacterial community structure relative to the conventional and the TILL without fertiliser systems. In all management systems, the rewetting event clearly modified microbial community structure and activity. Both returned to their pre-drought state after 28 days. However, the magnitude of variation of C mineralisation was lower (i.e. the resistance to stress was higher) in the NO-TILL system. The genetic structure of the NO-TILL bacterial communities was most modified by water-stress and exhibited a slower recovery rate. This suggests that land use management can increase microbial functional resistance to drought stress via the establishment of bacterial communities with particular metabolic capacities. Nevertheless, the resilience rates of C mineralisation were similar among management regimes, suggesting that similar mechanisms occur, maybe due to a common soil microbial community legacy.
Auteurs, date et publication :
Auteurs Aurore Kaisermann , Adélaïde Roguet , Naoise Nunan , Pierre-Alain Maron , Nicholas Ostle , Jean-Christophe Lata
Publication : Soil Biology and Biochemistry
Date : 2013
Volume : 66
Pages : 69-77
Catégorie(s)
#Genosol #INRAERésumé
The establishment of the range of soil biodiversity found within European soils is needed to guide EU policy development regarding the protection of soil. Such a base-line should be collated from a wide-ranging sampling campaign to ensure that soil biodiversity from the majority of soil types, land-use or management systems, and European climatic (bio-geographical zones) were included. This paper reports the design and testing of a method to achieve the large scale sampling associated with the establishment of such a baseline, carried out within the remit of the EcoFINDERS project, and outlines points to consider when such a task is undertaken. Applying a GIS spatial selection process, a sampling campaign was undertaken by 13 EcoFINDERS partners across 11 countries providing data on the range of indicators of biodiversity and ecosystem functions including; micro and meso fauna biodiversity, extracellular enzyme activity, PLFA and community level physiological profiling (MicroResp™ and Biolog™). Physical, chemical and bio-geographical parameters of the 81 sites sampled were used to determine whether the model predicted a wide enough range of sites to allow assessment of the biodiversity indicators tested. Discrimination between the major bio-geographical zones of Atlantic and Continental was possible for all land-use types. Boreal and Alpine zones only allowed discrimination in the most common land-use type for that area e.g. forestry and grassland sites, respectively, while the Mediterranean zone did not have enough sites sampled to draw conclusions across all land-use types. The method used allowed the inclusion of a range of land-uses in both the model prediction stage and the final sites sampled. The establishment of the range of soil biodiversity across Europe is possible, though a larger targeted campaign is recommended. The techniques applied within the EcoFINDERS sampling would be applicable to a larger campaign.
Auteurs, date et publication :
Auteurs D. Stone , P. Blomkvist , N. Bohse Hendriksen , M. Bonkowski , H. Bracht Jørgensen , F. Carvalho , M. B. Dunbar , C. Gardi , S. Geisen , R. Griffiths , A. S. Hug , J. Jensen , H. Laudon , S. Mendes , P. V. Morais , A. Orgiazzi , P. Plassart , J. Römbke , M. Rutgers , R. M. Schmelz
Publication : Applied Soil Ecology
Date : 2016
Volume : 97
Pages : 3-11