Thunen Institute

Braunschweig, Germany

Thunen Institute

Braunschweig, Germany
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PubMed | Karlsruhe Institute of Technology, Thunen Institute, Scotland’s Rural College, CNR Institute for Agricultural and Forest Systems In the Mediterranean and 5 more.
Type: | Journal: The Science of the total environment | Year: 2016

The identification of site-specific agricultural management practices in order to maximize yield while minimizing environmental nitrogen losses remains in the center of environmental pollution research. Here, we used the biogeochemical model LandscapeDNDC to explore different agricultural practices with regard to their potential to reduce soil N2O emissions and NO3 leaching while maintaining yields. In a first step, the model was tested against observations of N2O emissions, NO3 leaching, soil micrometeorology as well as crop growth for eight European cropland and grassland sites. Across sites, LandscapeDNDC predicts very well mean N2O emissions (r(2)=0.99) and simulates the magnitude and general temporal dynamics of soil inorganic nitrogen pools. For the assessment of site-specific mitigation potentials of environmental nitrogen losses a Monte Carlo optimization technique considering different agricultural management options (i.e., timing of planting, harvest and fertilization, amount of applied fertilizer as well as residue management) was used. The identified optimized field management practices reduce N2O emissions and NO3 leaching from croplands on average by 21% and 31%, respectively. Likewise, average reductions of 55% for N2O emissions and 16% for NO3 leaching are estimated for grasslands. For mitigating environmental loss - while maintaining yield levels - it was most important to reduce fertilizer application rates by in average 10%. Our analyses indicate that yield scaled N2O emissions and NO3 leaching indicate possible improvements of nitrogen use efficiencies in European farming systems. Moreover, the applied optimization approach can be used also in a prognostic way to predict optimal timings and fertilization options (rates and splitting) upon accurate weather forecasts combined with the knowledge of modeled soil nutrient availability and plant nitrogen demand.

Belaya V.,Thunen Institute | Hanf J.H.,Geisenheim University
Agricultural and Food Economics | Year: 2016

The importance of power is underlined by many scientists who view it as a key behavioral construct. Power distinguishes itself as an effective tool in coordinating and promoting harmonious relationships, solving conflicts, and enhancing performance. An important challenge is to determine what role power plays in managing business-to-business relationships with specific attention to coordination and cooperation. The aim of our work is to investigate the role of power in business-to-business relationships to work out a strategy that enables managers to select an effective mix of power mechanisms. We work out and test a theoretical model of the effects of power on cooperation and coordination in business-to-business relationships and discuss possible managerial implications. To verify our research hypotheses, we conduct expert interviews via telephone about relationships of international food processing companies with their suppliers in Russia. © 2016, The Author(s).

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.

Since January 2010 in Germany no permission exists for keeping laying hens in conventional cages - two years before the EU regulation comes into force. Alternative systems like floor keeping, aviaries and small group systems must follow the intentions of the society with high animal welfare requirements. Nevertheless protection of work and the environment cannot be neglected for evaluation and comparison of different systems. Concentration of ammonia in and emissions from the stables were measured as 1 h spot once a month. Furthermore 24 h monitoring is added for each stable once in a quarter of a year to have the opportunity to indicate how the spot measurements reflect the diurnal profile and how seasonal effects must be considered. The paper gives a comprehensive view to the measuring procedure and the results of the investigations which show a wide span for the concentrations and emissions of ammonia for different alternative keepings of laying hens.

Beck W.,Thunen Institute | Sanders T.G.M.,Thunen Institute | Pofahl U.,University of Greifswald
Dendrochronologia | Year: 2013

Analysing climate-growth relationships is one of the key areas in dendrochronological research. One problem however remained unsolved - the discrepancy between the trees continuous growth over the vegetation period and the mean climate variables stretching over much longer periods. Here we present the possibility to calculate climate-growth correlations based on daily climate data using variable temporal width together with moving correlations to accommodate for short term as well as long term influences on tree growth. For the first time this offers the opportunity to acknowledge annual changes in the growing seasonal length and effects of short extreme events. Numerous outputs in data- and graphic-files allows a comparison of varying periods with significant correlations between climate and tree growth. Furthermore the use of climate scenarios is an optional tool for growth predictions. © 2012 Elsevier GmbH.

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.

Tietz A.,Thunen Institute | Forstner B.,Thunen Institute | Weingarten P.,Thunen Institute
German Journal of Agricultural Economics | Year: 2013

Investments in agricultural land have recently gained particular public attention both in the international and national context. In Germany, the recent increase in sale and rental prices for agricultural land has often been linked to the activities of non-agricultural investors. The aim of this study is to take stock of these activities and to explore the relevance of nonagricultural and supra-regional investors. Further, it is aimed at investigating the impact of such activities on the land market, agricultural structures and regional development. Four regional case studies are carried out, three of them in the New Länder (former GDR). In each case study region, structured interviews were conducted with about ten farm managers and ten regional experts. Results show that the group of 'non-agricultural investors' is very heterogeneous and cannot be delimited by clear indicators. Thus, the core question about the relevance of their activities can only be answered with respect to the type of investor. Judgements as regards their impact are highly dependent on the selection of regional case studies, the type of interviewees and their respective interests.

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.

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.

PubMed | Thunen Institute, Johannes Gutenberg University Mainz and Alfred Wegener Institute for Polar and Marine Research
Type: Journal Article | Journal: Marine pollution bulletin | Year: 2016

Plastic ingestion by marine biota has been reported for a variety of different taxa. In this study, we investigated 290 gastrointestinal tracts of demersal (cod, dab and flounder) and pelagic fish species (herring and mackerel) from the North and Baltic Sea for the occurrence of plastic ingestion. In 5.5% of all investigated fishes, plastic particles were detected, with 74% of all particles being in the microplastic (<5mm) size range. The polymer types of all found particles were analysed by means of Fourier transform infrared (FT-IR) spectroscopy. Almost 40% of the particles consisted of polyethylene (PE). In 3.4% of the demersal and 10.7% of the pelagic individuals, plastic ingestion was recorded, showing a significantly higher ingestion frequency in the pelagic feeders. The condition factor K was calculated to test differences in the fitness status between individuals with and without ingested plastic, but no direct effect was detected.

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