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| Titel |
Immobilization of copper by biochar in Cu-enriched agricultural soils
depends on interactions with soil organic carbon |
| VerfasserIn |
Slađana Mlinkov, Franz Zehetner, Franz Rosner, Georg Dersch, Gerhard Soja |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250144157
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| Publikation (Nr.) |
 EGU/EGU2017-7950.pdf |
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| Zusammenfassung |
| The appearance of downy mildew (Plasmopara viticola) in European vineyards of the 19th
century was the starting point for the search of effective fungicides to avoid severe yield
losses. Copper has been found as an important ingredient for several fungicides that have
been used in agriculture and horticulture. For organic viticulture, several diseases can
only be antagonized with Cu-containing fungicides as the application of organic
fungicides is not permitted. This long-lasting dependence on Cu-fungicides has led to a
gradual Cu enrichment of vineyard soils in traditional wine-growing areas, locally
exceeding 300 mg/kg. Although these concentrations do not affect the vines or wine
quality, they may impair soil microbiological functions in the top soil layer or the root
growth of green cover plants. Therefore, measures are demanded that reduce the
bioavailability of copper, thereby reducing the ecotoxicological effects. The use
of biochar and compost as soil amendment has been suggested as a strategy to
immobilize Cu and reduce the exchangeable fractions. In our study we have tested the
hypothesis that biochar immobilizes the bioavailability of Cu for soil cover crops
and reduces soil pore water concentrations. This study had the objective to test the
interactions of compost and biochar with respect to Cu immobilization in vineyard
soils.
A Cu-enriched vineyard soil (250 mg Cu kg−1) was analyzed both in greenhouse and
field experiments. In both experiments, soil with or without biochar and/or compost and
mixtures of the two components were used. In the greenhouse experiments, was used as test
plant Lolium multiflorum for Cu uptake; in the field, Lolium perenne and Trifolium repens
were analyzed.
Greenhouse experiment: Soil pore water concentrations showed clearer differences in Cu
concentration than Lolium multiflorum shoots. Compost increased dissolved organic carbon
(DOC) and Cu in soil pore water and biochar reduced it significantly. The mixtures of
compost and biochar produced intermediate results.
Field experiment: Cu concentrations in the roots of soil cover crops were higher than
above-ground parts. Biochar as soil additive (4 kg m−2) and a biochar-compost mixture at a
high application rate (10 kg m−2) reduced the Cu uptake into the roots. Compost without
biochar or the mixture at a lower dose (4 kg m−2) either had no or even a mobilizing
effect on Cu. Apparently the effects of compost and biochar are opposite. Biochar is
only able to exert an immobilizing effect if soil organic carbon content is not too
high; otherwise only very high biochar addition rates can counteract the effect of
compost.
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