The European organic food market - how to increase its transparency?

Der Europäische Markt für ökologische Lebensmittel ist seit den 1990er Jahren stark gewachsen. Begünstigt wurde dies durch die Einführung der EU-Richtlinie 2092/91 zur Zertifizierung ökologischer Produkte und durch die Zahlung von Subventionen an umstellungswillige Landwirte. Diese Maßnahmen führten am Ende der 1990er Jahre für einige ökologische Produkte zu einem Überangebot auf europäischer Ebene. Die Verbrauchernachfrage stieg nicht in gleichem Maße wie das Angebot, und die Notwendigkeit für eine Verbesserung des Marktgleichgewichts wurde offensichtlich. Dieser Bedarf wurde im Jahr 2004 von der Europäischen Kommission im ersten „Europäischen Aktionsplan für ökologisch erzeugte Lebensmittel und den ökologischen Landbau“ formuliert. Als Voraussetzung für ein gleichmäßigeres Marktwachstum wird in diesem Aktionsplan die Schaffung eines transparenteren Marktes durch die Erhebung statistischer Daten über Produktion und Verbrauch ökologischer Produkte gefordert. Die Umsetzung dieses Aktionsplans ist jedoch bislang nicht befriedigend, da es auf EU-Ebene noch immer keine einheitliche Datenerfassung für den Öko-Sektor gibt. Ziel dieser Studie ist es, angemessene Methoden für die Erhebung, Verarbeitung und Analyse von Öko-Marktdaten zu finden. Geeignete Datenquellen werden identifiziert und es wird untersucht, wie die erhobenen Daten auf Plausibilität untersucht werden können. Hierzu wird ein umfangreicher Datensatz zum Öko-Markt analysiert, der im Rahmen des EU-Forschungsprojektes „Organic Marketing Initiatives and Rural Development” (OMIaRD) erhoben wurde und alle EU-15-Länder sowie Tschechien, Slowenien, Norwegen und die Schweiz abdeckt. Daten für folgende Öko-Produktgruppen werden untersucht: Getreide, Kartoffeln, Gemüse, Obst, Milch, Rindfleisch, Schaf- und Ziegenfleisch, Schweinefleisch, Geflügelfleisch und Eier. Ein zentraler Ansatz dieser Studie ist das Aufstellen von Öko-Versorgungsbilanzen, die einen zusammenfassenden Überblick von Angebot und Nachfrage der jeweiligen Produktgruppen liefern. Folgende Schlüsselvariablen werden untersucht: Öko-Produktion, Öko-Verkäufe, Öko-Verbrauch, Öko-Außenhandel, Öko-Erzeugerpreise und Öko-Verbraucherpreise. Zudem werden die Öko-Marktdaten in Relation zu den entsprechenden Zahlen für den Gesamtmarkt (öko plus konventionell) gesetzt, um die Bedeutung des Öko-Sektors auf Produkt- und Länderebene beurteilen zu können. Für die Datenerhebung werden Primär- und Sekundärforschung eingesetzt. Als Sekundärquellen werden Publikationen von Marktforschungsinstituten, Öko-Erzeugerverbänden und wissenschaftlichen Instituten ausgewertet. Empirische Daten zum Öko-Markt werden im Rahmen von umfangreichen Interviews mit Marktexperten in allen beteiligten Ländern erhoben. Die Daten werden mit Korrelations- und Regressionsanalysen untersucht, und es werden Hypothesen über vermutete Zusammenhänge zwischen Schlüsselvariablen des Öko-Marktes getestet. Die Datenbasis dieser Studie bezieht sich auf ein einzelnes Jahr und stellt damit einen Schnappschuss der Öko-Marktsituation der EU dar. Um die Marktakteure in die Lage zu versetzen, zukünftige Markttrends voraussagen zu können, wird der Aufbau eines EU-weiten Öko-Marktdaten-Erfassungssystems gefordert. Hierzu wird eine harmonisierte Datenerfassung in allen EU-Ländern gemäß einheitlicher Standards benötigt. Die Zusammenstellung der Marktdaten für den Öko-Sektor sollte kompatibel sein mit den Methoden und Variablen der bereits existierenden Eurostat-Datenbank für den gesamten Agrarmarkt (öko plus konventionell). Eine jährlich aktualisierte Öko-Markt-Datenbank würde die Transparenz des Öko-Marktes erhöhen und die zukünftige Entwicklung des Öko-Sektors erleichtern. ---------------------------

Local food security and principle of organic farming (from farm to fork) in context of food culture in Indonesia: Minangkabau's case study

The basic idea behind improving local food security consists of two paths; first, accessibility (price, stock) and second, availability (quantity and biodiversity); both are perquisites to the provision of nutrients and a continuous food supply with locally available resources. The objectives of this thesis are to investigate if indigenous knowledge still plays an important role in traditional farming in the Minangkabau`s culture, thus supporting local food security. If the indigenous knowledge still plays a role in food culture in the Minangkabau`s culture which is linked to the matrilineal role and leads to a sound nutrition. Further, it should be tested if marantau influences traditional farming and food culture in Minangkabau`s, and if the local government plays a role in changing of traditional farming systems and food culture. Furthermore this thesis wants to prove if education and gender are playing a role in changing traditional farming system and food culture, and if the mass media affects traditional farming systems and food culture for the Minangkabau. The study was completed at four locations in West Sumatera; Nagari Ulakan (NU) (coastal area), Nagari Aia Batumbuak (NAB) (hilly area), Nagari Padang Laweh Malalo (NPLM) (lake area), Nagari Pandai Sikek (NPS) (hilly area). The rainfall ranged from 1400- 4800 mm annually with fertile soils. Data was collected by using PRA (Participatory Rural Appraisal) to investigate indigenous knowledge (IK) and its interactions, which is also combining with in depth-interview, life history, a survey using semi-structured-questionnaire, pictures, mapping, and expert interview. The data was collected from June - September 2009 and June 2010. The materials are; map of area, list of names, questionnaires, voices recorder, note book, and digital camera. The sampling method was snowball sampling which resulted in the qualitative and quantitative data taken. For qualitative data, ethnography and life history was used. For quantitative, a statistical survey with a semi-structured questionnaire was used. 50 respondents per each site participated voluntarily. Data was analyzed by performing MAXQDA 10, and F4 audio analysis software (created and developed by Philip-University Marburg). The data is clustered based on causality. The results show that; the role of IK on TFS (traditional farming system) shown on NPLM which has higher food crop biodiversity in comparison to the other three places even though it has relatively similar temperature and rainfall. This high food crop biodiversity is due to the awareness of local people who realized that they lived in unfavourable climate and topography; therefore they are more prepared for any changes that may occur. Carbohydrate intake is 100 % through rice even though they are growing different staple crops. Whereas most of the people said in the interviews that not eating rice is like not really eating for them. In addition to that, mothers still play an important role in kitchen activities. But when the agriculture income is low, mothers have to decide whether to change the meals or to feel insecure about their food supply. Marantau yields positive impact through the remittances it provides to invest on the farm. On the other hand, it results in fewer workers for agriculture, and therefore a negative impact on the transfer of IK. The investigation showed that the local government has a PTS (Padi Tanam Sabatang) programme which still does not guarantee that the farmers are getting sufficient revenue from their land. The low agricultural income leads to situation of potential food insecurity. It is evident that education is equal among men and women, but in some cases women tend to leave school earlier because of arranged marriages or the distances of school from their homes. Men predominantly work in agriculture and fishing, while women work in the kitchen. In NAB, even though women work on farmland they earn less then men. Weaving (NPS) and kitchen activity is recognized as women’s work, which also supports the household income. Mass media is not yielding any changes in TFS and food culture in these days. The traditional farming system has changed because of intensive agricultural extension which has introduced new methods of agriculture for the last three decades (since the 1980’s). There is no evidence that they want to change any of their food habits because of the mass media despite the lapau activity which allows them to get more food choices, instead preparing traditional meal at home. The recommendations of this thesis are: 1) The empowerment of farmers. It is regarding the self sufficient supply of manure, cooperative seed, and sustainable farm management. Farmers should know – where are they in their state of knowledge – so they can use their local wisdom and still collaborate with new sources of knowledge. Farmers should learn the prognosis of supply and demand next prior to harvest. There is a need for farm management guidelines; that can be adopted from both their local wisdom and modern knowledge. 2) Increase of non-agricultural income Increasing the non-agricultural income is strongly recommended. The remittances can be invested on non-agricultural jobs. 3) The empowerment of the mother. The mother plays an important role in farm to fork activities; the mother can be an initiator and promoter of cultivating spices in the backyard. Improvement of nutritional knowledge through information and informal public education can be done through arisan ibu-ibu and lapau activity. The challenges to apply these recommendations are: 1) The gap between institutions and organizations of local governments. There is more than one institution involved in food security policy. 2) Training and facilities for field extension agriculture (FEA) is needed because the rapid change of interaction between local government and farmer’s dependent on this agency.

Gaseous and leaching losses of carbon and nitrogen in irrigated organic farming of a coastal oasis in Oman

In der Dissertation wurden die Effekte verschiedener C/N-Verhältnisse und verschiedener Verhältnisse von strukturellen zu löslichen Kohlenhydraten (NDF/SC) von Dung, der in bewässerten Gemüsekulturen im Norden Omans appliziert wurde, untersucht. Im auf sandigen Böden durchgeführten Experiment wurden zwei Büffeldungvarianten zum einen mit einem C/N-Verhältnis von 19 und einem NDF/SC-Verhältnis von 17 (ORG1) und zum anderen mit einem C/N-Verhältnis von 25 und einem NDF/SC-Verhältnis von 108 (ORG2) verwendet. Das relevante faktorielle Anbausystem war eine zweijährige Rotation, bestehend aus Rettich gefolgt von Blumenkohl und Karotte. Eine signifikante Zunahme der Erträge, des Sproßdurchmessers und der Pflanzenhöhe von Blumenkohl (P<0,001) sowie der Konzentration von Askorbinsäure in den Wurzeln von Rettich (P<0,01) mit erhöhter Verfügbarkeit von N, P und K von ORG2 über ORG1 bis hin zur Mineraldünger-Kontrollbehandlung (MIN) konnte festgestellt werden. Innerhalb von 260 Tagen wurden für die gesamte Anbauperiode mit einem photoakustischen Infrarot-Multigasmonitor und einer damit verbundenen Haube bodenbürtige Gasemissionen gemessen. Die errechneten Nettobilanzen zeigten Überschüsse von N und P, welche von Defiziten für K begleitet waren. Die Kohlenstoff Nettobilanzen waren während des Untersuchungszeitraums negativ oder nicht konsistent. Die Ergebnisse zeigen, dass unter extremen klimatischen Bedingungen bewässerter sandiger Böden organische Kultivierung zuerst durch den Kohlenstoffgehalt von Dung und Boden und erst dann durch die applizierten Mengen an N, P und K limitiert wird. Es konnte festgestellt werden, dass Gasemissionen den größten Teil der N und C Verluste von bewässerten sandigen Böden im Norden Omans darstellen. Die Reduzierung von Treibhausgasen und Sickerverlusten sollte weiterhin im Fokus zukünftiger Untersuchungen stehen, um zur Entwicklung von nachhaltigen organischen Anbausystemen im Oman und anderen ariden tropischen Ländern beizutragen.

Labelling schemes for organic food: Consumer attitudes, preferences and willingness-to-pay in six European countries

Since July 2010, all pre-packed organic food produced in the European Union (EU) must carry the new mandatory EU logo for organic food. Voluntary organic labels (such as national governmental logos and logos of private farmers’ associations and control bodies) can still be used, but only in addition to the mandatory EU logo. This change in the regulatory environment of organic labelling raises a number of questions regarding consumer preferences for different kinds of organic certification logos, which the present dissertation addressed. The first objective was to explore and analyse consumer perceptions, attitudes, preferences and willingness-to-pay (WTP) regarding different voluntary organic labels. The second objective was to investigate consumer perceptions and attitudes towards a mandatory EU logo. A combination of qualitative and quantitative methods of consumer research in six European countries was employed including focus group discussions, choice experiments and structured interviews. Based on the empirical results, recommendations are drawn for different actors in the organic sector.

Attitudes and behaviour towards food attributes and organic food – a triangular methodological investigation of occasional organic consumers

Organic food is increasingly available in the conventional food retail, where organic products are offered alongside with various other types of products and compete mainly with conventional and the so-called conventional-plus products. The latter are conventional products displaying particular quality attributes on the product packaging, such as ‘no artificial additives’, or ‘from animal welfare husbandry’. Often, these quality attributes also apply to organic products. Occasional organic consumers might prefer such conventional-plus alternatives that are perceived to be ‘between’ organic and conventional products. The overall objective of this PhD thesis was to provide information about the segment of occasional organic consumers. In particular, the thesis focussed on consumer perceptions and attitudes towards the quality of, and preferences for, organic, conventional and conventional-plus products in two countries: Germany and Switzerland. To achieve these objectives, qualitative and quantitative consumer research was combined in order to explore occasional organic consumers’ perceptions and attitudes as well as to observe their preferences and buying behaviour regarding different types of food products: organic, conventional and conventional-plus products. The qualitative research showed that, depending on single criteria, organic production was both positively as well as negatively assessed by consumers. Consumer perception of organic food was found to be highly selective and primarily focussed on the final stage of the particular production process. A major problem is that consumers are still mostly unfamiliar with factors associated with organic production, have a lack of confidence, and often confuse organic with conventional products. Besides this, consumer expectations of organic products are different from the expectations of conventional products. The quantitative research revealed that attitudes strongly determine consumers’ preferences for organic, conventional and conventional-plus products. Consumer attitudes tended to differ more between organic and conventional choices rather than conventional-plus and conventional choices. Furthermore, occasional organic consumers are heterogeneous in their preferences. They can be grouped into two segments: the consumers in one segment were less price sensitive and preferred organic products. The consumers in the other segment were more price sensitive and rather preferred conventional-plus or conventional products. To conclude, given the selective and subjective nature of consumer perception and the strong focus of consumer perception on the final stage of the food production process, specific additional values of organic farming should be communicated in clear and catchy messages. At the same time, these messages should be particularly focussed on the final stage of organic food production. The communication of specific added values in relation with organic products to improve the perceived price-performance-ratio is important since conventional-plus products represent an interesting alternative particularly for price sensitive occasional organic consumers. Besides this, it is important to strengthen affirmative consumer attitudes towards organic production. Therefore, policy support should emphasise on long-term communication campaigns and education programmes to increase the consumer awareness and knowledge of organic food and farming. Since consumers expect that organic food is regionally or at least domestically produced while they less accept organic imports, policy support of domestic and regional producers is a crucial measure to fill the current gap between the increasing consumer demand of organic food and the stagnation of the domestic and regional organic food supply.

Synthesis and characterisation of novel nitrogen and fluorine containing spirobifluorene derivatives for electronic applications and crystal engineering

Among organic materials, spirobifluorene derivatives represent a very attractive class of materials for electronic devices. These compounds have high melting points, glass transitions temperatures and morphological stability, which makes these materials suitable for organic electronic applications. In addition, some of spirobifluorenes can form porous supramolecular associations with significant volumes available for the inclusion of guests. These molecular associations based on the spirobifluorenes are noteworthy because they are purely molecular analogues of zeolites and other microporous solids, with potential applications in separation, catalysis, sensing and other areas.

Factors influencing a conversion to organic farming in Nepalese tea farms

Organic agriculture in developing countries has increased in past decades especially due to the high demand of organic products in developed countries. The rate of conversion to organic production in Nepal, however, is observed much slower than expected. This study investigates factors that determine the conversion to organic production using Nepalese tea producers as a case study. A survey of 181 farmers was conducted in the Ilam and Panchthar district of Nepal, among which 86 were organic farmers and 95 were conventional farmers. A discriminant analysis was used to identify socio-economic characteristics that distinguish conventional and organic farmers. Results from the estimated discriminant function suggest that farmers located in a distance from regional markets, older in age, better trained, affiliated with institutions and having larger farms are more likely to adopt organic production. Similarly, a factor analysis shows that environmental awareness, bright market prospects, observable economic benefit and health consciousness are the major factors influencing farmers’ decisions on the conversion to organic production. While planning programs for the development of the organic tea sector in Nepal, policy makers should consider the support of farmers’ institutions, provision of training to farmers and raise farmers’ awareness about the environmental, economic and health benefits of organic farming.

Effects of Organic and Inorganic Fertilizers on Growth and Yield of Banana (Musa AAA cv. Malindi) in Oman

The Sultanate of Oman is located on the south-eastern coast of the Arabian Peninsula, which lies on the south-western tip of the Asian continent. The strategic geographical locations of the Sultanate with its many maritime ports distributed on the Indian Ocean have historically made it one of the Arabian Peninsula leaders in the international maritime trade sector. Intensive trading relationships over long time periods have contributed to the high plant diversity seen in Oman where agricultural production depends entirely on irrigation from groundwater sources. As a consequence of the expansion of the irrigated area, groundwater depletion has increased, leading to the intrusion of seawater into freshwater aquifers. This phenomenon has caused water and soil salinity problems in large parts of the Al-Batinah governorate of Oman and threatens cultivated crops, including banana (Musa spp.). According to the Ministry of Agriculture and Fisheries, the majority of South Al-Batinah farms are affected by salinity (ECe > 4 dS m-1). As no alternative farmland is available, the reclamation of salt-affected soils using simple cultural practices is of paramount importance, but in Oman little scientific research has been conducted to develop such methods of reclamation. This doctoral study was initiated to help filling this research gap, particularly for bananas. A literature review of the banana cultivation history revealed that the banana germplasm on the Arabian Peninsula is probably introduced from Indonesia and India via maritime routes across the Indian Ocean and the Red Sea. In a second part of this dissertation, two experiments are described. A laboratory trial conducted at the University of Kassel, in Witzenhausen, Germany from June to July 2010. This incubation experiment was done to explore how C and N mineralization of composted dairy manure and date palm straw differed in alkaline non-saline and saline soils. Each soil was amended with four organic fertilizers: 1) composted dairy manure, 2) manure + 10% date palm straw, 3) manure + 30% date palm straw or 4) date palm straw alone, in addition to un-amended soils as control. The results showed that the saline soil had a lower soil organic C content and microbial biomass C than the non-saline soil. This led to lower mineralization rates of manure and date palm straw in the saline soil. In the non-saline soil, the application of manure and straw resulted in significant increases of CO2 emissions, equivalent to 2.5 and 30% of the added C, respectively. In the non-amended control treatment of the saline soil, the sum of CO2-C reached only 55% of the soil organic C in comparison with the non-saline soil. In which 66% of the added manure and 75% of the added straw were emitted, assuming that no interactions occurred between soil organic C, manure C and straw C during microbial decomposition. The application of straw always led to a net N immobilization compared to the control. Salinity had no specific effect on N mineralization as indicated by the CO2-C to Nmin ratio of soil organic matter and manure. However, N immobilization was markedly stronger in the saline soil. Date palm straw strongly promoted saprotrophic fungi in contrast to manure and the combined application of manure and date palm straw had synergistic positive effects on soil microorganisms. In the last week of incubation, net-N mineralization was observed in nearly all treatments. The strongest increase in microbial biomass C was observed in the manure + straw treatment. In both soils, manure had no effect on the fungi-specific membrane component ergosterol. In contrast, the application of straw resulted in strong increases of the ergosterol content. A field experiment was conducted on two adjacent fields at the Agricultural Research Station, Rumais (23°41’15” N, 57°59’1” E) in the South of Al-Batinah Plain in Oman from October 2007 to July 2009. In this experiment, the effects of 24 soil and fertilizer treatments on the growth and productivity of Musa AAA cv. 'Malindi' were evaluated. The treatments consisted of two soil types (saline and amended non-saline), two fertilizer application methods (mixed and ring applied), six fertilizer amendments (1: fresh dairy manure, 2: composted dairy manure, 3: composted dairy manure and 10% date palm straw, 4: composted dairy manure and 30% date palm straw, 5: only NPK, and 6: NPK and micronutrients). Sandy loam soil was imported from another part of Oman to amended the soil in the planting holes and create non-saline conditions in the root-zone. The results indicate that replacing the saline soil in the root zone by non-saline soil improved plant growth and yield more than fertilizer amendments or application methods. Particularly those plants on amended soil where NPK was applied using the ring method and which received micronutrients grew significantly faster to harvest (339 days), had a higher average bunch weight (9.5 kg/bunch) and were consequently more productive (10.6 tonnes/hectare/cycle) compared to the other treatments.

Organische Mikro- und Nanodrähte auf Basis von Perylendiimiden

Diese Arbeit thematisiert die optimierte Darstellung von organischen Mikro- und Nanodrähten, Untersuchungen bezüglich deren molekularen Aufbaus und die anwendungsorientierte Charakterisierung der Eigenschaften. Mikro- und Nanodrähte haben in den letzten Jahren im Zuge der Miniaturisierung von Technologien an weitreichendem Interesse gewonnen. Solche eindimensionalen Strukturen, deren Durchmesser im Bereich weniger zehn Nanometer bis zu einigen wenigen Mikrometern liegt, sind Gegenstand intensiver Forschung. Neben anorganischen Ausgangssubstanzen zur Erzeugung von Mikro- und Nanodrähten haben organische Funktionsmaterialien aufgrund ihrer einfachen und kostengünstigen Verarbeitbarkeit sowie ihrer interessanten elektrischen und optischen Eigenschaften an Bedeutung gewonnen. Eine wichtige Materialklasse ist in diesem Zusammenhang die Verbindungsklasse der n-halbleitenden Perylentetracarbonsäurediimide (kurz Perylendiimide). Dem erfolgreichen Einsatz von eindimensionalen Strukturen als miniaturisierte Bausteine geht die optimierte und kontrollierte Herstellung voraus. Im Rahmen der Doktorarbeit wurde die neue Methode der Drahterzeugung „Trocknen unter Lösungsmittelatmosphäre“ entwickelt, welche auf Selbstassemblierung der Substanzmoleküle aus Lösung basiert und unter dem Einfluss von Lösungsmitteldampf direkt auf einem vorgegebenen Substrat stattfindet. Im Gegensatz zu literaturbekannten Methoden ist kein Transfer der Drähte aus einem Reaktionsgefäß nötig und damit verbundene Beschädigungen der Strukturen werden vermieden. Während herkömmliche Methoden in einer unkontrolliert großen Menge von ineinander verwundenen Drähten resultieren, erlaubt die substratbasierte Technik die Bildung voneinander separierter Einzelfasern und somit beispielsweise den Einsatz in Einzelstrukturbauteilen. Die erhaltenen Fasern sind morphologisch sehr gleichmäßig und weisen bei Längen von bis zu 5 mm bemerkenswert hohe Aspektverhältnisse von über 10000 auf. Darüber hinaus kann durch das direkte Drahtwachstum auf dem Substrat über den Einsatz von vorstrukturierten Oberflächen und Wachstumsmasken gerichtetes, lokal beschränktes Drahtwachstum erzielt werden und damit aktive Kontrolle auf Richtung und Wachstumsbereich der makroskopisch nicht handhabbaren Objekte ausgeübt werden. Um das Drahtwachstum auch hinsichtlich der Materialauswahl, d. h. der eingesetzten Ausgangsmaterialien zur Drahterzeugung und somit der resultierenden Eigenschaften der gebildeten Strukturen aktiv kontrollieren zu können, wird der Einfluss unterschiedlicher Parameter auf die Morphologie der Selbstassemblierungsprodukte am Beispiel unterschiedlicher Derivate betrachtet. So stellt sich zum einen die Art der eingesetzten Lösungsmittel in flüssiger und gasförmiger Phase beim Trocknen unter Lösungsmittelatmosphäre als wichtiger Faktor heraus. Beide Lösungsmittel dienen als Interaktionspartner für die Moleküle des funktionellen Drahtmaterials im Selbstassemblierungsprozess. Spezifische Wechselwirkungen zwischen Perylendiimid-Molekülen untereinander und mit Lösungsmittel-Molekülen bestimmen dabei die äußere Form der erhaltenen Strukturen. Ein weiterer wichtiger Faktor ist die Molekülstruktur des verwendeten funktionellen Perylendiimids. Es wird der Einfluss einer Bay-Substitution bzw. einer unsymmetrischen Imid-Substitution auf die Morphologie der erhaltenen Strukturen herausgestellt. Für das detaillierte Verständnis des Zusammenhanges zwischen Molekülstruktur und nötigen Wachstumsbedingungen für die Bildung von eindimensionalen Strukturen zum einen, aber auch die resultierenden Eigenschaften der erhaltenen Aggregationsprodukte zum anderen, sind Informationen über den molekularen Aufbau von großer Bedeutung. Im Rahmen der Doktorarbeit konnte ein molekular hoch geordneter, kristalliner Aufbau der Drähte nachgewiesen werden. Durch Kombination unterschiedlicher Messmethoden ist es gelungen, die molekulare Anordnung in Strukturen aus einem Spirobifluoren-substituierten Derivat in Form einer verkippten Molekülstapelung entlang der Drahtlängsrichtung zu bestimmen. Um mögliche Anwendungsbereiche der erzeugten Drähte aufzuzeigen, wurden diese hinsichtlich ihrer elektrischen und optischen Eigenschaften analysiert. Neben dem potentiellen Einsatz im Bereich von Filteranwendungen und Sensoren, sind vor allem die halbleitenden und optisch wellenleitenden Eigenschaften hervorzuheben. Es konnten organische Transistoren auf der Basis von Einzeldrähten mit im Vergleich zu Dünnschichtbauteilen erhöhten Ladungsträgerbeweglichkeiten präpariert werden. Darüber hinaus wurden die erzeugten eindimensionalen Strukturen als aktive optische Wellenleiter charakterisiert. Die im Rahmen der Dissertation erarbeiteten Kenntnisse bezüglich der Bildung von eindimensionalen Strukturen durch Selbstassemblierung, des Drahtaufbaus und erster anwendungsorientierter Charakterisierung stellen eine Basis zur Weiterentwicklung solcher miniaturisierter Bausteine für unterschiedlichste Anwendungen dar. Die neu entwickelte Methode des Trocknens unter Lösungsmittelatmosphäre ist nicht auf den Einsatz von Perylendiimiden beschränkt, sondern kann auf andere Substanzklassen ausgeweitet werden. Dies eröffnet breite Möglichkeiten der Materialauswahl und somit der Einsatzmöglichkeiten der erhaltenen Strukturen.

Effects of different tillage treatments on labile soil organic matter pools and stabilization processes

An improved understanding of soil organic carbon (Corg) dynamics in interaction with the mechanisms of soil structure formation is important in terms of sustainable agriculture and reduction of environmental costs of agricultural ecosystems. However, information on physical and chemical processes influencing formation and stabilization of water stable aggregates in association with Corg sequestration is scarce. Long term soil experiments are important in evaluating open questions about management induced effects on soil Corg dynamics in interaction with soil structure formation. The objectives of the present thesis were: (i) to determine the long term impacts of different tillage treatments on the interaction between macro aggregation (>250 µm) and light fraction (LF) distribution and on C sequestration in plots differing in soil texture and climatic conditions. (ii) to determine the impact of different tillage treatments on temporal changes in the size distribution of water stable aggregates and on macro aggregate turnover. (iii) to evaluate the macro aggregate rebuilding in soils with varying initial Corg contents, organic matter (OM) amendments and clay contents in a short term incubation experiment. Soil samples were taken in 0-5 cm, 5-25 cm and 25-40 cm depth from up to four commercially used fields located in arable loess regions of eastern and southern Germany after 18-25 years of different tillage treatments with almost identical experimental setups per site. At each site, one large field with spatially homogenous soil properties was divided into three plots. One of the following three tillage treatments was carried in each plot: (i) Conventional tillage (CT) with annual mouldboard ploughing to 25-30 cm (ii) mulch tillage (MT) with a cultivator or disc harrow 10-15 cm deep, and (iii) no tillage (NT) with direct drilling. The crop rotation at each site consisted of sugar beet (Beta vulgaris L.) - winter wheat (Triticum aestivum L.) - winter wheat. Crop residues were left on the field and crop management was carried out following the regional standards of agricultural practice. To investigate the above mentioned research objectives, three experiments were conducted: Experiment (i) was performed with soils sampled from four sites in April 2010 (wheat stand). Experiment (ii) was conducted with soils sampled from three sites in April 2010, September 2011 (after harvest or sugar beet stand), November 2011 (after tillage) and April 2012 (bare soil or wheat stand). An incubation study (experiment (iii)) was performed with soil sampled from one site in April 2010. Based on the aforementioned research objectives and experiments the main findings were: (i) Consistent results were found between the four long term tillage fields, varying in texture and climatic conditions. Correlation analysis of the yields of macro aggregate against the yields of free LF ( ≤1.8 g cm-3) and occluded LF, respectively, suggested that the effective litter translocation in higher soil depths and higher litter input under CT and MT compensated in the long term the higher physical impact by tillage equipment than under NT. The Corg stocks (kg Corg m−2) in 522 kg soil, based on the equivalent soil mass approach (CT: 0–40 cm, MT: 0–38 cm, NT: 0–36 cm) increased in the order CT (5.2) = NT (5.2) < MT (5.7). Significantly (p ≤ 0.05) highest Corg stocks under MT were probably a result of high crop yields in combination with reduced physical tillage impact and effective litter incorporation, resulting in a Corg sequestration rate of 31 g C-2 m-2 yr-1. (ii) Significantly higher yields of macro aggregates (g kg-2 soil) under NT (732-777) and MT (680-726) than under CT (542-631) were generally restricted to the 0-5 cm sampling depth for all sampling dates. Temporal changes on aggregate size distribution were only small and no tillage induced net effect was detectable. Thus, we assume that the physical impact by tillage equipment was only small or the impact was compensated by a higher soil mixing and effective litter translocation into higher soil depths under CT, which probably resulted in a high re aggregation. (iii) The short term incubation study showed that macro aggregate yields (g kg-2 soil) were higher after 28 days in soils receiving OM (121.4-363.0) than in the control soils (22.0-52.0), accompanied by higher contents of microbial biomass carbon and ergosterol. Highest soil respiration rates after OM amendments within the first three days of incubation indicated that macro aggregate formation is a fast process. Most of the rebuilt macro aggregates were formed within the first seven days of incubation (42-75%). Nevertheless, it was ongoing throughout the entire 28 days of incubation, which was indicated by higher soil respiration rates at the end of the incubation period in OM amended soils than in the control soils. At the same time, decreasing carbon contents within macro aggregates over time indicated that newly occluded OM within the rebuilt macro aggregates served as Corg source for microbial biomass. The different clay contents played only minor role in macro aggregate formation under the particular conditions of the incubation study. Overall, no net changes on macro aggregation were identified in the short term. Furthermore, no indications for an effective Corg sequestration on the long term under NT in comparison to CT were found. The interaction of soil disturbance, litter distribution and the fast re aggregation suggested that a distinct steady state per tillage treatment in terms of soil aggregation was established. However, continuous application of MT with a combination of reduced physical tillage impact and effective litter incorporation may offer some potential in improving the soil structure and may therefore prevent incorporated LF from rapid decomposition and result in a higher C sequestration on the long term.

Organic consumers' attitudes and preferences regarding alternatives to piglet castration without anaesthesia and analgesia in organic farming - an explorative analysis

In Germany and other European countries piglets are routinely castrated in order to avoid the occurrence of boar taint, an off-flavour and off-odour of pork. Sensory perception of boar taint varies; however, it is regarded as very unpleasant by many people. Surgical castration which is an effective means against boar taint has commonly been performed without anaesthesia or analgesia within the piglets’ first seven days of life. Piglet castration without anaesthesia has been heavily criticised, as the assumption that young piglets perceive less pain than older animals cannot be supported by scientific evidence. Consequently, surgical castration is only allowed with anaesthesia and/or analgesia in organic farming throughout the European Union since January 2012. Abandoning piglet castration without pain relief requires the implementation of alternative methods which improve animal welfare while maintaining sensory meat quality. There are three relevant alternatives: castration with anaesthesia and/or analgesia to reduce pain, a vaccination against boar taint (immunocastration) and the fattening of uncastrated male pigs (fattening of boars) combined with measures to reduce and detect boar taint in meat. Consumers’ attitudes and opinions regarding the alternatives are an important factor with regard to the implementation of alternatives, as they are finally supposed to buy the meat. The objective of this dissertation was to explore organic consumers’ attitudes, preferences and willingness-to-pay regarding piglet castration without pain relief and the three alternatives. Important aspects for the evaluation of the alternatives and influencing factors (e.g. information, taste) on preferences and willingness-to-pay should also be identified. In autumn 2009 nine focus group discussions were conducted each followed by a Vickrey auction including a tasting of boar salami. Overall, 89 consumers of organic pork participated in the study. Information on piglet castration and alternatives (in three variants) was provided as a basis for discussion. The focus group data were analysed using qualitative content analysis. In order to compare the focus group results with those from the auctions, an innovative approach applying an adapted scoring model to further analyse the data set was used. The majority of participants were not aware that piglets are castrated without anaesthesia in organic farming. They reacted shocked and disappointed on learning about this practice which did not fit into their image of animal welfare standards in organic farming. Overall, the results show, that for consumers of organic pork castration with anaesthesia and analgesia as well as the fattening of boars may be acceptable alternatives in organic farming. Considering the strong food safety concerns regarding immunocastration, acceptance of this alternative may be questioned. Communication regarding alternatives to piglet castration without anaesthesia and analgesia should take into account that the relevance of the aspects animal welfare, food safety, taste and costs differs between alternatives. Furthermore, it seems advisable not to address an unappetizing topic like piglet castration directly at the point of sale so as not to deter consumers from buying organic pork. The issue of piglet castration demonstrates exemplarily that it is important for the organic sector to implement and maintain high animal welfare standards and communicate them in an appropriate way, thereby trying to prevent strong discrepancies between consumers’ expectations regarding animal husbandry in organic farming and actual conditions. So, disappointment of consumers and a loss of image due to negative reports about animal welfare issues can be avoided.

Optical Characterization of Organic Gain Materials for UV-emitting Hybrid Complex Coupled VCSELs

In this thesis, optical gain measurement setup based on variable stripe length method is designed, implemented and improved. The setup is characterized using inorganic and organic samples. The optical gain of spiro-quaterphenyl is calculated and compared with measurements from the setup. Films with various thicknesses of spiro-quaterphenyl, methoxy-spiro-quaterphenyl and phenoxy-spiro-quaterphenyl are deposited by a vacuum vapor deposition technique forming asymmetric slab waveguides. The optical properties, laser emission threshold, optical gain and loss coefficient for these films are measured. Additionally, the photodegradation during pumping process is investigated.

Soil, water and nutrient loss under conventional and organic vegetable production managed in small farms

Agricultural systems with conventional tillage and intensive use of agrochemicals, especially those on high slopes and with shallow soils, have the potential to release pollutants. This study aimed at evaluating the soil, water and nutrient lost via agricultural runoff in large plots (small catchments) under conventional and organic farming of vegetables as well as under forest (control) system in a Cambisol in the Campestre catchment. Samples of runoff were collected biweekly for one year through a Coshocton wheel. The soil and water losses from the conventional farming were 218 and 6 times higher, respectively, than forest. Under organic farming the soil and water losses were 12 and 4 times higher, respectively, than forest. However the soil losses (0.5 to 114 kg ha^(−1) year^(−1)) are considered low in agronomy but environmentally represent a potential source of surface water contamination by runoff associated pollutants. The concentrations and losses of all forms of phosphorus (P) were higher in the conventional system (9.5, 0.9 and 0.3 mg L^(−1) of total P for conventional, organic and forest systems, respectively), while the organic system had the highest concentrations and losses of soluble nitrogen (4.7, 38.6 and 0.4 mg L^(−1) of NO_3-N, respectively). The percentage of bioavailable P was proportionally higher in the organic system (91% of total P lost was as bioavailable P), indicating greater potential for pollution in the short term.

Happy growers! Relationship quality in the German organic apple chain

Relational factors between supply chain actors have been acknowledged to contribute significantly to competitiveness. With the example of the German market for organic apples the suitability of the concept of the Relational View for explaining competitiveness was investigated. Structured interviews were conducted with selected actors of the supply chain. Actors at all levels of the supply chain proved to be highly committed and described their business relations as satisfying and trustful. Strong vertical and horizontal collaboration was found. Thus, the Relational View proved to be highly suitable to explain competitiveness in the market for organic apples.