 |
| Titel |
Mineralisation, leaching and stabilisation of 13C-labelled leaf and twig litter in a beech forest soil |
| VerfasserIn |
A. Kammer, F. Hagedorn |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 8, no. 8 ; Nr. 8, no. 8 (2011-08-17), S.2195-2208 |
| Datensatznummer |
250006079
|
| Publikation (Nr.) |
 copernicus.org/bg-8-2195-2011.pdf |
|
|
|
|
|
| Zusammenfassung |
| Very few field studies have quantified the different pathways of C loss from
decomposing litter even though the partitioning of C fluxes is essential to
understand soil C dynamics. Using 0.75 kg m−2 of 13C-depleted leaf
(δ13C = −40.8 ‰) and 2 kg m−2 of twig litter
(δ13C = −38.4 ‰), we tracked the litter-derived C in soil CO2
effluxes, dissolved organic C (DOC), and soil organic matter of a beech
forest in the Swiss Jura. Autotrophic respiration was reduced by trenching.
Our results show that mineralisation was the main pathway of C loss from
decomposing litter over 1 yr, amounting to 24 and 31 % of the added twig
and leaf litter. Contrary to our expectations, the leaf litter C was
mineralised only slightly (1.2 times) more rapidly than the twig litter C.
The leaching of DOC from twigs amounted to half of that from leaves
throughout the experiment (2 vs. 4 % of added litter C). Tracing the
litter-derived DOC in the soil showed that DOC from both litter types was
mostly removed (88–96 %) with passage through the top centimetres of the
mineral soil (0–5 cm) where it might have been stabilised. In the soil
organic C at 0–2 cm depth, we indeed recovered 4 % of the initial twig C
and 8 % of the leaf C after 1 yr. Much of the 13C-depleted litter
remained on the soil surface throughout the experiment: 60 % of the twig
litter C and 25 % of the leaf litter C. From the gap in the 13C-mass
balance based on C mineralisation, DOC leaching, C input into top soils, and
remaining litter, we inferred that another 30 % of the leaf C but only
10 % of twig C could have been transported via soil fauna to soil depths
below 2 cm. In summary, over 1 yr, twig litter was mineralised more
rapidly relative to leaf litter than expected, and much less of the
twig-derived C was transported to the mineral soil than of the leaf-derived
C. Both findings provide some evidence that twig litter could contribute
less to the C storage in these base-rich forest soils than leaf litter. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|