Agricultural management affects the response of soil bacterial community structure and respiration to water-stress

• Published in: Soil biology & biochemistry Vol. 66; pp. 69 - 77
• Main Authors: Kaisermann, Aurore, Roguet, Adélaïde, Nunan, Naoise, Maron, Pierre-Alain, Ostle, Nicholas, Lata, Jean-Christophe
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.11.2013; Elsevier
• Subjects: Agricultural land use; agricultural management; Agronomy. Soil science and plant productions; Bacteria; bacterial communities; Bacterial community structure; Biochemistry and biology; Biological and medical sciences; C mineralisation; carbon; carbon dioxide; carbon sequestration; carbon sinks; Chemical, physicochemical, biochemical and biological properties; climate change; community structure; conventional tillage; drought; drought tolerance; Drying–rewetting; Environmental Sciences; field experimentation; Fundamental and applied biological sciences. Psychology; Global change; land use planning; Life Sciences; management systems; mineralization; no-tillage; organic matter; Physics, chemistry, biochemistry and biology of agricultural and forest soils; respiratory rate; soil; soil bacteria; soil ecology; soil organic matter; Soil science; Stability; stress tolerance; Vegetal Biology; water stress; Stability; Drying–rewetting; Bacterial community structure; Agricultural land use; C mineralisation; Global change; Community structure; Farmland; Water stress; Land use; Carbon cycle; Soils; Mineralization; Bacteria; Agriculture; Rewetting; Drying-rewetting; Respiration; Microbial community; Drying; CATABOLIC DIVERSITY; NITROGEN MINERALIZATION; RESILIENCE; FUNCTIONAL STABILITY; ORGANIC-MATTER; CLIMATE-CHANGE; MICROBIAL COMMUNITY; CARBON STOCKS; LAND-USE CHANGE; DRYING-REWETTING FREQUENCY
• ISSN: 0038-0717; 1879-3428
• DOI: 10.1016/j.soilbio.2013.07.001

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. •Carbon enrichment after land use conversion do not confer greater microbial stability.•Community structure and activity are resilient after a dry rewetting event.•Resilience rate of bacterial community structure differs between land use.•Functional resistance is affected by agriculture reconversion.