title: Effects of different biochars and digestate on N2O fluxes under field conditions.
abstract: Field studies that have investigated the effects of char materials on the emission of nitrous oxide (N2O) are still scarce. Therefore, we conducted a field trial with bio- and hydrochars and measured N2O emissions for one whole year. It was hypothesised that the incorporation of chars reduces the emissions of N2O. Chars were produced by pyrolysis and hydrothermal carbonisation (HTC) using either maize silage or wood residues as feedstock. In addition, after production chars were post-treated with digestate in order to accelerate the ageing process of the chars. Chars and digestate were applied to the soil to raise the C content. Emissions of N2O were measured weekly and soil samples for inorganic nitrogen (N) and soil water-content were taken once a month. Additionally, the abundance of functional marker genes from denitrification (nosZ) was determined in October 2012 and in June 2013. The treatment with pure digestate emitted the most N2O compared to the control and char treatments. However, this was significant only in one case. There were no great differences between the char treatments due to high spatial variability and gene abundance of nosZ did not differ between treatments. Overall, emissions of N2O were relatively low. This was attributed to the heterogeneous distribution of the chars and the sandy soils that did not favour the production of N2O. To conclude, the emissions of N2O were mainly influenced by temperature and precipitation and to a minor extent by the type of char and post-treatment.
authors.affiliation: Leibniz-Institute for Agricultural Engineering Potsdam-Bornim e. V., Max-Eyth-Allee 100, 14469 Potsdam, Germany. Electronic address: cdicke@atb-potsdam.de.
authors.forename: Christiane
authors.initials: C
authors.lastname: Dicke
authors.affiliation: Leibniz-Institute for Agricultural Engineering Potsdam-Bornim e. V., Max-Eyth-Allee 100, 14469 Potsdam, Germany. Electronic address: jandert@atb-potsdam.de.
authors.forename: Janet
authors.initials: J
authors.lastname: Andert
authors.affiliation: Leibniz-Institute for Agricultural Engineering Potsdam-Bornim e. V., Max-Eyth-Allee 100, 14469 Potsdam, Germany. Electronic address: cammon@atb-potsdam.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Ammon
authors.affiliation: Leibniz-Institute for Agricultural Engineering Potsdam-Bornim e. V., Max-Eyth-Allee 100, 14469 Potsdam, Germany. Electronic address: jkern@atb-potsdam.de.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Kern
authors.affiliation: Leibniz-Institute for Agricultural Engineering Potsdam-Bornim e. V., Max-Eyth-Allee 100, 14469 Potsdam, Germany. Electronic address: ameyer-aurich@atb-potsdam.de.
authors.forename: Andreas
authors.initials: A
authors.lastname: Meyer-Aurich
authors.affiliation: Technical University of Berlin, Department of Soil Science, Ernst-Reuter-Platz 1, 10587 Berlin, Germany. Electronic address: martin.kaupenjohann@tu-berlin.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Kaupenjohann
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001673:Biodegradation, Environmental; D002606:Charcoal / Q000737:chemistry*; D058440:Denitrification; D004784:Environmental Monitoring; D009609:Nitrous Oxide / Q000032:analysis*; D012987:Soil / Q000737:chemistry
chemical_list: D000393:Air Pollutants; D012987:Soil; C540010:biochar; D002606:Charcoal; D009609:Nitrous Oxide
keywords: Digestate; Hydrothermal carbonization; Nitrous oxide; Post-treatment; Pyrolysis; nosZ