Bibcode
Fabiola, B.; Olivier, M.; Houdusse, F.; Fuentes, M.; Garcia, M. J. M.; Lévêque, J.; Yvin, J. C.; Maron, P. A.; Lemenager, D.
Referencia bibliográfica
EGU General Assembly 2012, held 22-27 April, 2012 in Vienna, Austria., p.14055
Fecha de publicación:
4
2012
Número de citas
0
Número de citas referidas
0
Descripción
Organic matter (OM) influences many of the soil functions and occupies a
central position in the global carbon cycle. At the scale of the
agro-ecosystem, primary productivity is dependent on the recycling of
soil organic matter (SOM) by the action of decomposers (mainly bacteria
and fungi), which mineralize organic compounds, releasing the nutrients
needed for plant growth. At a global scale, the recycling of the SOM
determines the carbon flux between soil and atmosphere, with major
consequences in terms of environmental quality. In this context, the
management of SOM stocks in agro-ecosystems is a major issue from which
depend the maintenance of the productivity and sustainability of
agricultural practices. The use of additional fertilizer appears to be a
promising way to achieve such management. These products have been
proven effectives in many field trials. However, their mode of action,
particularly in terms of impact on soil microbial component, is still
nearly unknown. In this context, this study aims to test the influence
of an additional fertilizer on (i) soil microbial communities (total
biomass, density of bacteria and fungi), and (ii) soil functioning in
terms of dynamics of organic matter. It is based on experiments in soil
microcosms which follow in parallel the kinetics of mineralization of
different organic carbon compartments (endogenous compartment: soil
organic matter; exogenous compartment: wheat residue provided) and the
dynamics of microbial communities after the addition of wheat residues
in soil. Two different soils were used to evaluate the influence of soil
physicochemical characteristics on the effect induced by the addition in
terms of fertilization. The first results show a significant effect of
the input of additional fertilizer on the dynamics of soil organic
matter. They also show that soil pH as well as the dose at which the
additional fertilizer is applied are important for modulating the
observed effect. Characterization of microbial communities by molecular
tools (quantification of molecular biomass, quantitative PCR of 16S and
18S ribosomal genes to quantify bacteria and fungi, respectively) will
allow linking the changes of the mineralization of carbon compartments
with the response of the soil microbial communities.