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| Titel |
Comparison of different methods to assess root litter carbon input to the soil in a young deciduous forest |
| VerfasserIn |
Pietro Panzacchi, Pietro Boldreghini, Lucia Cantoni, Paola Gioacchini, Giustino Tonon |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250041935
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| Zusammenfassung |
| Estimating fine root turnover and rhizodeposition remains a mayor challenge in natural
ecosystems studies. In the present research we estimated root litter carbon (C) imputs to the
soil during 2006 coupling one direct and one indirect method.
The study was carried out in a fifteen-year-old mixed hardwood plantation established in
northern Italy on a former agricultural land (Clay content ~60%). A first estimation of net
rhizodeposition was obtained by the application of an isotopic method by using in-growth
cores filled with “C4 soil”. Plastic mesh bags (2.5 cm diameter, 60 cm long, 0.5 cm mesh
size) were packed respecting the original soil bulk density with soil from a long term Zea
mais crop system (δ 13C = –22.0 ± 0.2 ) and placed in the soil at different distances from
the stem of trees. “Control” bags made with a special tissue, porous to water and gases but
impenetrable to roots, were also placed nearby. By using the mass balance approach the flux
of C to the soil was calculated. This latter estimation was then compared to the root
litter input estimated by the application of the total belowground carbon allocation
(TBCA) approach for forests far from the steady state that can be simplified as
follows:
Ra + Lr+ ÎrootC = TBCA = Rsoil --Ll+ ÎlitterC + ÎsoilC + ÎrootC
(1)
where and Rsoil is total soil respiration, Ra is autotrophic soil respiration estimated by
the “trenching method”, Lr and Ll are belowground and aboveground litter respectively,
ÎlitterC, ÎsoilC and ÎrootC are the variations of C of litter layer, soil and roots
respectively. From equation 1 it is possible to extrapolate Lr:
Lr = Rsoil --Ra+ ÎlitterC + ÎsoilC + ÎrootC (2)
The two methods, that have never been exploited with the aim to estimate
rhizodeposition, gave similar final results. Actually, the net rhizodeposition (C input to the
soil by root minus heterotrophic respiration) was 3.27 Mg of C ha-1 by isotopic
approach and the total rhizodeposition was 3.22 Mg of C ha-1 by TBCA approach. |
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