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- ItemNitrous oxide emissions from winter oilseed rape cultivation(Amsterdam [u.a.] : Elsevier, 2017) Ruser, Reiner; Fuß, Roland; Andres, Monique; Hegewald, Hannes; Kesenheimer, Katharina; Köbke, Sarah; Räbiger, Thomas; Quinones, Teresa Suarez; Augustin, Jürgen; Christen, Olaf; Dittert, Klaus; Kage, Henning; Lewandowski, Iris; Prochnow, Annette; Stichnothe, Heinz; Flessa, HeinzWinter oilseed rape (Brassica napus L., WOSR) is the major oil crop cultivated in Europe. Rapeseed oil is predominantly used for production of biodiesel. The framework of the European Renewable Energy Directive requires that use of biofuels achieves GHG savings of at least 50% compared to use of fossil fuel starting in 2018. However, N2O field emissions are estimated using emission factors that are not specific for the crop and associated with strong uncertainty. N2O field emissions are controlled by N fertilization and dominate the GHG balance of WOSR cropping due to the high global warming potential of N2O. Thus, field experiments were conducted to increase the data basis and subsequently derive a new WOSR-specific emission factor. N2O emissions and crop yields were monitored for three years over a range of N fertilization intensities at five study sites representative of German WOSR production. N2O fluxes exhibited the typical high spatial and temporal variability in dependence on soil texture, weather and nitrogen availability. The annual N2O emissions ranged between 0.24 kg and 5.48 kg N2O-N ha−1 a−1. N fertilization increased N2O emissions, particularly with the highest N treatment (240 kg N ha−1). Oil yield increased up to a fertilizer amount of 120 kg N ha−1, higher N-doses increased grain yield but decreased oil concentrations in the seeds. Consequently oil yield remained constant at higher N fertilization. Since, yield-related emission also increased exponentially with N surpluses, there is potential for reduction of the N fertilizer rate, which offers perspectives for the mitigation of GHG emissions. Our measurements double the published data basis of annual N2O flux measurements in WOSR. Based on this extended dataset we modeled the relationship between N2O emissions and fertilizer N input using an exponential model. The corresponding new N2O emission factor was 0.6% of applied fertilizer N for a common N fertilizer amount under best management practice in WOSR production (200 kg N ha−1 a−1). This factor is substantially lower than the linear IPCC Tier 1 factor (EF1) of 1.0% and other models that have been proposed. © 2017
- ItemA promising approach to low electrical percolation threshold in PMMA nanocomposites by using MWCNT-PEO predispersions(Oxford : Elsevier Science, 2016) Mir, Seyed Mohammad; Jafari, Seyed Hassan; Khonakdar, Hossein Ali; Krause, Beate; Pötschke, Petra; Taheri Qazvini, NaderElectrical conductive poly(methyl methacrylate) (PMMA) nanocomposites with low percolation threshold are very challenging to be prepared. Here, we show that the miscibility between poly(ethylene oxide) (PEO) as matrix for predispersions of multi-walled carbon nanotubes (MWCNTs) and PMMA represents an efficient approach to achieve very low electrical percolation threshold. PMMA/PEO-MWCNTs nanocomposites were prepared by a two-step solution casting method involving pre-mixing of MWCNTs with PEO and then mixing of PEO-MWCNTs with PMMA, resulting in a PMMA/PEO ratio of 80/20 wt%. The electrical percolation threshold (EPT) value was determined to be ~ 0.07 wt% which is significantly lower than most of the reported EPT values in the literature for PMMA/CNT composites. The very low electrical percolation threshold was attributed to the effectual role of PEO in self-assembly of secondary structures of nanotubes into an electrically conductive network. This was further confirmed by transmission electron microscopy and by comparing the obtained EPT value with the prediction of the excluded volume model in which statistical percolation threshold is defined based on uniform distribution of high-aspect ratio sticks in a matrix. Moreover, based on UV–Vis measurements and linear viscoelastic rheological measurements, optical and rheological percolation thresholds were obtained at nearly 0.01 wt% and 0.5 wt%, respectively.
- ItemRepresentativeness of European biochar research: part I–field experiments(Vilnius : Technika, 2017) Verheijen, Frank G. A.; Mankasingh, Utra; Penizek, Vit; Panzacchi, Pietro; Glaser, Bruno; Jeffery, Simon; Bastos, Ana Catarina; Tammeorg, Priit; Kern, Jürgen; Zavalloni, Costanza; Zanchettin, Giulia; Sakrabani, RubenA representativeness survey of existing European Biochar field experiments within the Biochar COST Action TD1107 was conducted to gather key information for setting up future experiments and collaborations, and to minimise duplication of efforts amongst European researchers. Woody feedstock biochar, applied without organic or inorganic fertiliser appears over-represented compared to other categories, especially considering the availability of crop residues, manures, and other organic waste streams and the efforts towards achieving a zero waste economy. Fertile arable soils were also over-represented while shallow unfertile soils were under-represented. Many of the latter are likely in agroforestry or forest plantation land use. The most studied theme was crop production. However, other themes that can provide evidence of mechanisms, as well as potential undesired side-effects, were relatively well represented. Biochar use for soil contamination remediation was the least represented theme; further work is needed to identify which specific contaminants, or mixtures of contaminants, have the potential for remediation by different biochars. © 2017 The Author(s) Published by VGTU Press and Informa UK Limited, [trading as Taylor & Francis Group].
- ItemSynergistic use of peat and charred material in growing media–an option to reduce the pressure on peatlands?(Vilnius : Technika, 2017) Kern, Jürgen; Tammeorg, Priit; Shanskiy, Merrit; Sakrabani, Ruben; Knicker, Heike; Kammann, Claudia; Tuhkanen, Eeva-Maria; Smidt, Geerd; Prasad, Munoo; Tiilikkala, Kari; Sohi, Saran; Gascó, Gabriel; Steiner, Christoph; Glaser, BrunoPeat is used as a high quality substrate for growing media in horticulture. However, unsustainable peat extraction damages peatland ecosystems, which disappeared to a large extent in Central and South Europe. Furthermore, disturbed peatlands are becoming a source of greenhouse gases due to drainage and excavation. This study is the result of a workshop within the EU COST Action TD1107 (Biochar as option for sustainable resource management), held in Tartu (Estonia) in 2015. The view of stakeholders were consulted on new biochar-based growing media and to what extent peat may be replaced in growing media by new compounds like carbonaceous materials from thermochemical conversion. First positive results from laboratory and greenhouse experiments have been reported with biochar content in growing media ranging up to 50%. Various companies have already started to use biochar as an additive in their growing media formulations. Biochar might play a more important role in replacing peat in growing media, when biochar is available, meets the quality requirements, and their use is economically feasible. © 2017 The Author(s) Published by VGTU Press and Informa UK Limited, [trading as Taylor & Francis Group].
- ItemBiochar as a tool to reduce the agricultural greenhouse-gas burden–knowns, unknowns and future research needs(Vilnius : Technika, 2017) Kammann, Claudia; Ippolito, Jim; Hagemann, Nikolas; Borchard, Nils; Cayuela, Maria Luz; Estavillo, José M.; Fuertes-Mendizabal, Teresa; Jeffery, Simon; Kern, Jürgen; Novak, Jeff; Rasse, Daniel; Saarnio, Sanna; Schmidt, Hans-Peter; Spokas, Kurt; Wrage-Mönnig, NicoleAgriculture and land use change has significantly increased atmospheric emissions of the non-CO2 green-house gases (GHG) nitrous oxide (N2O) and methane (CH4). Since human nutritional and bioenergy needs continue to increase, at a shrinking global land area for production, novel land management strategies are required that reduce the GHG footprint per unit of yield. Here we review the potential of biochar to reduce N2O and CH4 emissions from agricultural practices including potential mechanisms behind observed effects. Furthermore, we investigate alternative uses of biochar in agricultural land management that may significantly reduce the GHG-emissions-per-unit-of-product footprint, such as (i) pyrolysis of manures as hygienic alternative to direct soil application, (ii) using biochar as fertilizer carrier matrix for underfoot fertilization, biochar use (iii) as composting additive or (iv) as feed additive in animal husbandry or for manure treatment. We conclude that the largest future research needs lay in conducting life-cycle GHG assessments when using biochar as an on-farm management tool for nutrient-rich biomass waste streams. © 2017 The Author(s) Published by VGTU Press and Informa UK Limited, [trading as Taylor & Francis Group].
- ItemRepresentativeness of European biochar research: part II–pot and laboratory studies(Vilnius : Technika, 2017) Sakrabani, Ruben; Kern, Jürgen; Mankasingh, Utra; Zavalloni, Costanza; Zanchettin, Giulia; Bastos, Ana Catarina; Tammeorg, Priit; Jeffery, Simon; Glaser, Bruno; Verheijen, Frank G. A.Biochar research is extensive and there are many pot and laboratory studies carried out in Europe to investigate the mechanistic understanding that govern its impact on soil processes. A survey was conducted in order to find out how representative these studies under controlled experimental conditions are of actual environmental conditions in Europe and biomass availability and conversion technologies. The survey consisted of various key questions related to types of soil and biochar used, experimental conditions and effects of biochar additions on soil chemical, biological and physical properties. This representativeness study showed that soil texture and soil organic carbon contents used by researchers are well reflected in the current biochar research in Europe (through comparison with published literature), but less so for soil pH and soil type. This study provides scope for future work to complement existing research findings, avoiding unnecessary repetitions and highlighting existing research gaps. © 2017 The Author(s) Published by VGTU Press and Informa UK Limited, [trading as Taylor & Francis Group].
- ItemEditorial: special issue on biochar as an option for sustainable resource management (EU COST Action TD1107 final publication)(Vilnius : Technika, 2017) Glaser, Bruno; Baltrėnas, Pranas; Kammann, Claudia; Kern, Jürgen; Baltrėnaitė, EditaThe articles appearing in this special issue on Biochar as an Option for Sustainable Resource Management are mainly the extended versions of the contributions presented in Biochar COST Action meetings, especially at the International Biochar conference held September 2015 at Geisenheim University (Germany), which was the final conference of the COST Action TD1107. © 2017 Vilnius Gediminas Technical University (VGTU) Press.
- ItemAssessing the economic profitability of fodder legume production for Green Biorefineries – A cost-benefit analysis to evaluate farmers profitability(Amsterdam [u.a.] : Elsevier Science, 2016) Papendiek, Franka; Tartiu, Valentina E.; Morone, Piergiuseppe; Venus, Joachim; Hönig, AnneFodder legumes play a major role in developing sustainable agricultural production systems and contain a range of compounds, which can be utilized to produce a wide spectrum of materials currently manufactured from petroleum-based sources. Hence, if associated with Green Biorefinery technology, the use of fodder legumes brings about significant advantages in terms of overall environmental sustainability. Since fodder legume production in Europe is currently very low, the objective of this study is to assess if a new value chain generated by Green Biorefineries can make fodder legume production profitable for farmers, and therewith increase cultivation numbers. We conducted a financial cost-benefit analysis of producing biomass from agricultural land in the federal state of Brandenburg (Germany) in three different production scenarios at two farm size levels. Costs, benefits, expected profits and risks between the scenarios were quantified. Fodder legume production for traditional fodder production was already able to increase the internal rate of return, while the production of feedstocks for Green Biorefineries, depending on prices paid for the legume juice showed an even higher profit potential. Therefore, in future agricultural production systems, fodder legumes should be part of crop rotations again.
- ItemChange points of global temperature(Bristol : IOP Publ., 2015) Cahill, Niamh; Rahmstorf, Stefan; Parnell, Andrew C.We aim to address the question of whether or not there is a significant recent 'hiatus', 'pause' or 'slowdown' of global temperature rise. Using a statistical technique known as change point (CP) analysis we identify the changes in four global temperature records and estimate the rates of temperature rise before and after these changes occur. For each record the results indicate that three CPs are enough to accurately capture the variability in the data with no evidence of any detectable change in the global warming trend since ∼1970. We conclude that the term 'hiatus' or 'pause' cannot be statistically justified.
- ItemCorrigendum: The role of storage dynamics in annual wheat prices (2017 Environ. Res. Lett. 12 054005)(Bristol : IOP Publ., 2018) Schewe, Jacob; Otto, Christian; Frieler, Katja[no abstract available]