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| Titel |
Plants determine diversity and function of soil microbial and mesofaunal communities - results from a girdling experiments in a temperate coniferous forest |
| VerfasserIn |
J. Subke, N. Voke, V. Leronni, M. J. I. Briones, P. Ineson |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250023922
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| Zusammenfassung |
| The potential for carbon (C) sequestration in soils depends on the rate of humification of C
inputs to soils in relation to the decomposition of old soil organic matter. Recent results
indicate a close connection between the input of fresh organic matter and the decomposition
of old organic matter through soil priming. We conducted a tree girdling experiment in order
to better understand the interdependence of soil microbial communities and plant
belowground C allocation.
A girdling experiment in a mature Western Hemlock (Tsuga heterophylla) stand near
York (NE England) confirms the pattern observed in other girdling studies, with a reduction
in total soil CO2 efflux (RS) to about 60% of control plots following a delay of about 2
weeks. High frequency measurements of RS immediately after girdling show a short-lived
significant increase in RS in girdled plots between 3 and 8 hours after tree girdling, which
have not been observed previously. The autotrophic flux contribution (calculated as the
difference in RS between the control and girdled plots) declined throughout autumn, but in
contrast to most girdling studies, remained significantly greater than zero throughout during
December and January. This result indicates that tree belowground allocation continues
throughout winter, despite regular night-time frosts in the period measurement were taken.
Dominant mesofauna invertebrates (Enchytraeid worms) showed a positive response to
girdling and higher abundances were recorded in the girdled plots when compared
to the control ones, although differences were only significant on one sampling
occasion. These results suggest that, in contrast to other components of the soil
food-web, these organisms appear to be underpinned by detrital decomposition
rather than by recent photosynthate-C deposition. Litterbag incubations showed no
significant short-term treatment effect over the 4 months period following girdling,
indicating no measurable interaction of decomposition and plant activity by this
method.
The results emphasise the strong influence of plants on the composition and activity of
microbial soil communities. This has clear implications for our ability to predict ecosystem
response to environmental change, including shifts in land use managements, and
we discuss the need of incorporating these effects into current ecosystem models. |
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