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Please use this identifier to cite or link to this item:
http://hdl.handle.net/10174/28302
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Title: | Mulching-induced preservation of soil organic matter quality in a burnt eucalypt plantation in central Portugal |
Authors: | De la Rosa, José M. Jiménez-Morillo, Nicasio T González-Pérez, José A Almendros, Gonzalo Vieira, Diana Knicker, Heike Keizer, Jakob |
Keywords: | Mulching Humic acid Pyrogenic substance Wildfire |
Issue Date: | 2019 |
Abstract: | Mulching has amply proven its effectiveness to mitigate post-fire soil erosion but its impacts on soil organic
matter (SOM) quality and quantity continue poorly studied. The present study addressed this knowledge gap for
a eucalypt plantation in central Portugal that had been burnt and, immediately after the wildfire, mulched with
13.6 Mg ha−1 of eucalypt logging residues some five years before. This was done by performing a range of
analytical techniques (elemental and isotope analyses, analytical pyrolysis and 13C NMR spectroscopy) not only
on the bulk soil samples but also on their humic acids (HAs) and free organic matter (FOM) fractions. While
mulching reduced soil and SOM losses with 91 and 93%, respectively, it also improved SOM quality of the
topsoil, in particular in terms of HAs and FOM. At 0–4 cm depth, both HAs and FOM contents were roughly twice
as high in the mulched plots as in the control plots. The effects of mulching on the molecular composition of HAs
and FOM fractions, however, varied markedly. Analytical pyrolysis (Py-GC/MS) revealed that mulching had led
to a noticeable accumulation of labile, aliphatic SOM constituents such as carbohydrate-derived and alkyl
compounds (fatty acids and n-alkanes) but that it hardly affected the composition of HAs. Even so, solid-state 13C
NMR spectroscopy showed that mulching had resulted in a relative increase in aryl C in the FOM fraction,
suggesting an enhanced preservation of the pyrogenic OM. Overall, the combined use of a range of analytical
techniques allowed to conclude that, five years after their application, the forest logging residues had led to a
greater preservation of the fire-derived pyrogenic OM (mainly aromatic compounds) in the topsoil as well as to
higher contents of SOM's most labile molecular constituents (mainly carbohydrates and n-alkyl compounds). The
former reflected the reduced erosion rates, while the latter was probably due to a combination of reduced
erosion rates with the additional input of fresh organic matter |
URI: | https://doi.org/10.1016/j.jenvman.2018.10.114 http://hdl.handle.net/10174/28302 |
Type: | article |
Appears in Collections: | HERCULES - Publicações - Artigos em Revistas Internacionais Com Arbitragem Científica
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