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Braunschweig, Germany

Bargmann I.,Free University of Berlin | Bargmann I.,Julius Kuhn Institute | Martens R.,Thunen Institute | Rillig M.C.,Free University of Berlin | And 3 more authors.
Journal of Plant Nutrition and Soil Science | Year: 2014

Hydrochars and biochars are products of the carbonization of biomass in different conversion processes. Both are considered suitable soil amendments, though they differ greatly in chemical and physical composition (e.g., aromaticity, inner surface area) due to the different production processes (pyrolysis, hydrothermal carbonization), thus affecting their degradability in soil. Depending on the type, char application may provide soil microorganisms with more (hydrochars) or less (biochars) accessible C sources, thus resulting in the incorporation of nitrogen (N) into microbial biomass. A soil-incubation experiment was conducted for 8 weeks to determine the relationship between mineral-N concentration in the soil solution and microbial-biomass development as well as soil respiration. An arable topsoil was amended with two hydrochars from feedstocks with different total N contents. Biochars from the same feedstocks were used for comparison. Both char amendments significantly decreased mineral-N concentration and promoted microbial biomass compared to the nonamended control, but the effects were much stronger for hydrochar. Hydrochar application increased soil respiration significantly during the first week of incubation, simultaneous with the strongest decrease in mineral-N concentration in the soil and an increase in microbial biomass. The amount of N detected in the microbial biomass in the hydrochar treatments accounted for the mineral N "lost" from the soil during incubation. This shows that microbial immobilization is the main sink for decreasing mineral-N concentrations after hydrochar application. However, this does not apply to biochar, since the amount of N recovered in microorganisms was much lower than the decrease in soil mineral-N concentration. Our results demonstrate that while both chars are suitable soil amendments, their properties need to be considered to match the application purpose (C sequestration, organic fertilizer). © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Wagner K.,University of Veterinary Medicine Vienna | Barth K.,Thunen Institute | Hillmann E.,ETH Zurich | Palme R.,University of Veterinary Medicine Vienna | And 2 more authors.
Applied Animal Behaviour Science | Year: 2013

The aim of this study was to test the effects of mother rearing on behavioural and physiological stress reactions of calves in challenging situations. Thus, we compared mother-reared and artificially reared calves that were kept in the same group but with varying contact with adults. Mother-reared calves (Mother) were suckled and had unrestricted contact with their mothers and also with the cow herd in the cubicle barn; artificially reared calves were fed milk up to 16. kg per day and animal via an automatic milk feeder (Automat). At the age of 43 days, the calves were separated from the group for 15. min (isolation test; Mother: n= 16; Automat: n= 16), and at 90 days of age, they underwent a social confrontation test with an unfamiliar calf in an arena for 20. min (Mother: n= 11; Automat: n= 11). Data were analysed using ANOVA and GLMM. In the isolation test, Mother calves showed more (P< 0.05) escape behaviour and tended to be more vigilant (P< 0.1). Concerning physiological parameters, no differences were detected in the mean heart rate over 15. min of isolation, but the increase in salivary cortisol concentrations 5. min after the end of the test tended to be lower in Mother calves than in Automat calves (P< 0.1). During confrontation, Mother calves showed less frequently solitary play behaviour (i.e. mainly locomotor play) than Automat calves (P< 0.05) but initiated more frequently social play when no cow was present adjacent to the test arena (P< 0.05). The results suggest that mother-reared calves showed higher motivation to rejoin their mothers and/or herd and tried to cope more actively with being isolated. In addition, in the confrontation test Mother calves seemed to be socially more active and more attentive to their social environment, but less motivated for locomotor play possibly due to the much larger space available to them in the cow barn. © 2013 Elsevier B.V. Source

Belaya V.,Thunen Institute | Hanf J.H.,University Geisenheim
International Journal on Food System Dynamics | Year: 2016

Vertical collaborations in supply chains imply the achievement of mutual benefits for the participating partners such as increasing sales, reducing costs and risks and improving the overall performance. However, the benefits are sometimes difficult to gain due to existing differences in interests and goals of the individual chain members. Thus, conflicts are inevitable. Power can be seen as one of the mechanisms to resolve conflicts in supply chains. By and large, the findings provide support that power could have a profound impact on conflict resolution in vertical collaborations. However, in order to successfully resolve conflicts the knowledge of different power types is essential. Source

Styles D.,Bangor University | Gibbons J.,Bangor University | Williams A.P.,Bangor University | Stichnothe H.,Thunen Institute | And 2 more authors.
GCB Bioenergy | Year: 2015

On-farm anaerobic digestion (AD) of wastes and crops can potentially avoid greenhouse gas (GHG) emissions, but incurs extensive environmental effects via carbon and nitrogen cycles and substitution of multiple processes within and outside farm system boundaries. Farm models were combined with consequential life cycle assessment (CLCA) to assess plausible biogas and miscanthus heating pellet scenarios on dairy farms. On the large dairy farm, the introduction of slurry-only AD led to reductions in global warming potential (GWP) and resource depletion burdens of 14% and 67%, respectively, but eutrophication and acidification burden increases of 9% and 10%, respectively, assuming open tank digestate storage. Marginal GWP burdens per Mg dry matter (DM) feedstock codigested with slurry ranged from -637 kg CO2e for food waste to +509 kg CO2e for maize. Codigestion of grass and maize led to increased imports of concentrate feed to the farm, negating the GWP benefits of grid electricity substitution. Attributing grass-to-arable land use change (LUC) to marginal wheat feed production led to net GWP burdens exceeding 900 kg CO2e Mg-1 maize DM codigested. Converting the medium-sized dairy farm to a beef-plus-AD farm led to a minor reduction in GWP when grass-to-arable LUC was excluded, but a 38% GWP increase when such LUC was attributed to marginal maize and wheat feed required for intensive compensatory milk production. If marginal animal feed is derived from soybeans cultivated on recently converted cropland in South America, the net GWP burden increases to 4099 kg CO2e Mg-1 maize DM codigested - equivalent to 55 Mg CO2e yr-1 per hectare used for AD-maize cultivation. We conclude that AD of slurry and food waste on dairy farms is an effective GHG mitigation option, but that the quantity of codigested crops should be strictly limited to avoid potentially large international carbon leakage via animal feed displacement. © 2015 John Wiley & Sons Ltd. Source

Hudjetz S.,RWTH Aachen | Herrmann H.,RWTH Aachen | Cofalla C.,RWTH Aachen | Brinkmann M.,RWTH Aachen | And 6 more authors.
Environmental Science and Pollution Research | Year: 2014

There is a consensus within the scientific community that sediments act as a long-term sink for a variety of organic and inorganic pollutants, which, however, can re-enter the water column upon resuspension of deposited material under certain hydraulic conditions such as flood events. Within the implementation of the European Water Framework Directive, it is important to understand the potential short- and long-term impact of suspended particulate matter (SPM)-associated contaminants on aquatic organisms as well as the related uptake mechanisms for a sound risk assessment. To elucidate the effects of sediment-bound organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), rainbow trout (Oncorhynchus mykiss) were exposed to three resuspended natural sediments with different contamination levels. Physicochemical parameters including dissolved oxygen concentration, pH and temperature, total PAH concentration in sediments and SPM as well as different biomarkers of exposure in fish (7-ethoxyresorufin O-deethylase activity, biliary PAH metabolites, micronuclei, and lipid peroxidation) were measured following seven days of exposure within an annular flume, a device to assess erosion and deposition processes of cohesive sediment. Concentrations of PAHs in SPM remained constant and represented the different contamination levels in the un-suspended sediments. Significant differences in bile metabolite concentrations as well as in 7-ethoxyresorufin O-deethylase induction compared to control experiments (untreated animals and animals that were exposed in the annular flume without sediment) were observed for all exposure scenarios. The ratio between 1-hydroxypyrene in bile from fish exposed to the three different contamination levels was 1.0:3.6:10.7 and correlated well with (1) the ratio of pyrene concentrations in corresponding sediments which was 1.0:3.1:12.7 and (2) with the ratio of particle-bound pyrene in SPM which was 1.0:2.7:11.7. In contrast, hepatic lipid peroxidation and micronuclei formation represented the different contamination levels less conclusive. The results of this study clearly demonstrate that firmly bound PAH from aged sediments can become bioaccessible upon resuspension under flood-like conditions and are readily absorbed by aquatic organisms such as rainbow trout. Associated short-term effects were clearly documented and possible adverse long-term impacts due to genotoxicity are likely to follow. © 2013, Springer-Verlag Berlin Heidelberg. Source

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