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| Titel |
Effect of Biochar on Greenhouse Gas Emissions and Nitrogen Cycling in Laboratory and Field Experiments |
| VerfasserIn |
Nikolas Hagemann, Johannes Harter, Radina Kaldamukova, Reiner Ruser, Simone Graeff-Hönninger, Andreas Kappler, Sebastian Behrens |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250090720
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| Publikation (Nr.) |
 EGU/EGU2014-4973.pdf |
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| Zusammenfassung |
| The extensive use of nitrogen (N) fertilizers in agriculture is a major source of anthropogenic
N2O emissions contributing 8% to global greenhouse gas emissions. Soil biochar amendment
has been suggested as a means to reduce both CO2 and non-CO2 greenhouse gas emissions.
The reduction of N2O emissions by biochar has been demonstrated repeatedly in field
and laboratory experiments. However, the mechanisms of the reduction remain
unclear. Further it is not known how biochar field-weathering affects GHG emissions
and how agro-chemicals, such as the nitrification inhibitor 3,4–dimethylpyrazole
phosphate (DMPP), that is often simultaneously applied together with commercial
N-fertilizers, impact nitrogen transformation and N2O emissions from biochar amended
soils.
In order investigate the duration of the biochar effect on soil N2O emissions and its
susceptibility to DMPP application we performed a microcosm and field study with a
high-temperature (400 °C) beech wood derived biochar (60 t ha-1 and 5 % (w/w)
biochar in the field and microcosms, respectively). While the field site contained
the biochar already for three years, soil and biochar were freshly mixed for the
laboratory microcosm experiments. In both studies we quantified GHG emissions and
soil nitrogen speciation (nitrate, nitrite, ammonium). While the field study was
carried out over the whole vegetation period of the sunflower Helianthus annuus L.,
soil microcosm experiments were performed for up to 9 days at 28°C. In both
experiments a N-fertilizer containing DMPP was applied either before planting of the
sunflowers or at the beginning of soil microcosms incubation. Laboratory microcosm
experiments were performed at 60% water filled pore space reflecting average field
conditions.
Our results show that biochar effectively reduced soil N2O emissions by up to 60 % in the
field and in the soil microcosm experiments. No significant differences in N2O emission
mitigation potential between field-aged and fresh biochar were observed for the specific
biochar used in this study. N2O emission reduction occurred even in the presence of DMPP in
the field and in the laboratory microcosms. Our results suggest that simultaneous
measurements of soil samples from the same field site in the laboratory yield similar biochar
effects to those quantified in the field and that the mechanisms of N2O mitigation seem to be
independent of plant growth and application of the commercial nitrification inhibitor DMPP. |
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