title: Contrasting effects of biochar on N2O emission and N uptake at different N fertilizer levels on a temperate sandy loam.
abstract: Biochar has been frequently suggested as an amendment to improve soil quality and mitigate climate change. To investigate the optimal management of nitrogen (N) fertilization, we examined the combined effect of biochar and N fertilizer on plant N uptake and N2O emissions in a cereal rotation system in a randomized two-factorial field experiment on a sandy loam soil in Brandenburg, Germany. The biochar treatment received 10Mgha-1wood-derived biochar in September 2012. Four levels of N fertilizer, corresponding to 0, 50%, 100%, 130% of the recommended fertilizer level, were applied in winter wheat (Triticum aestivum L.)) and winter rye (Secale cereal L.) in 2013 and 2014 followed by the catch crop oil radish (Raphanus sativus L. var. oleiformis). Biomass and N uptake of winter wheat and winter rye were significantly affected by the level of N fertilizer but not by biochar. For N uptake of oil radish an interaction effect was observed for biochar and N fertilizer. Without applied fertilizer, 39% higher N uptake was found in the presence of biochar, accompanied by higher soil NH4+content and elevated cumulative CO2emissions. At 130% of the recommended fertilizer level, 16% lower N uptake and lower cumulative N2O emissions were found in the biochar-mediated treatment. No significant change in abundance of microbial groups and nosZ gene were observed. Our results highlight that biochar can have a greenhouse gas mitigation effect at high levels of N supply and may stimulate nutrient uptake when no N is supplied.
authors.affiliation: Leibniz-Institute for Agricultural Engineering and Bioeconomy, Potsdam, Germany; College of Environment and Resources, Anhui Agricultural Univeristy, Hefei, China.
authors.forename: Zhencai
authors.initials: Z
authors.lastname: Sun
authors.affiliation: Leibniz-Institute for Agricultural Engineering and Bioeconomy, Potsdam, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Sänger
authors.affiliation: Leibniz Centre for Agricultural Landscape Research (ZALF), Institute of Landscape Biogeochemistry, Müncheberg, Germany.
authors.forename: Philip
authors.initials: P
authors.lastname: Rebensburg
authors.affiliation: Leibniz Centre for Agricultural Landscape Research (ZALF), Institute of Landscape Biogeochemistry, Müncheberg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Lentzsch
authors.affiliation: Leibniz Centre for Agricultural Landscape Research (ZALF), Institute of Landscape Biogeochemistry, Müncheberg, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Wirth
authors.affiliation: Technical University of Berlin, Department of Soil Science, Berlin, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Kaupenjohann
authors.affiliation: Leibniz-Institute for Agricultural Engineering and Bioeconomy, Potsdam, Germany. Electronic address: ameyer-aurich@atb-potsdam.de.
authors.forename: Andreas
authors.initials: A
authors.lastname: Meyer-Aurich
keywords: Greenhouse gas emissions; Microbial community; nosZ gene