Microbially managed organic growing media for greenhouse horticulture

The production of vegetables in growing media is an efficient way to produce vegetables in soilless culture systems. The management of the microbial community associated with growing media may serve as potential sustainable pathway to increase eco-efficiency. Consequently, it is important to find out how biotic and abiotic factors affect the composition and diversity of microbial communities associated with growing media. The aim of this PhD thesis was to study the ecology of the microbial community in soilless culture systems. First, the microbial community of a mineral and an organic growing medium was examined and it was found that both growing media have a distinct, microbial community structure. Second, key functionalities of growing media and their individual constituents were quantified. Particularly, the nitrogen dynamics were studied in relation to the microbial community associated with plant and growing medium. Third, the valorization of recycled nutrients as a high-value microalgae fertilizer and struvite was investigated. In addition, an adapted fertigation strategy in combination with organic fertilizers was developed to narrow the yield gap with a pure mineral growing medium when cultivating tomatoes. Afterwards, the microbial community structure of four contrasting soil and soilless tomato cultivating systems were studied. Finally, the effect of fertilizers and plant type on the microbial community structure of the rhizosphere and the bulk zone were investigated. Overall, organic growing media show a potential for developing novel cultivating systems fitting into a more sustainable horticulture

Growing media constituents determine the microbial nitrogen conversions in organic growing media for horticulture

Vegetables and fruits are an important part of a healthy food diet, however, the eco-sustainability of the production of these can still be significantly improved. European farmers and consumers spend an estimated Euro15.5 billion per year on inorganic fertilizers and the production of N-fertilizers results in a high carbon footprint. We investigated if fertilizer type and medium constituents determine microbial nitrogen conversions in organic growing media and can be used as a next step towards a more sustainable horticulture. We demonstrated that growing media constituents showed differences in urea hydrolysis, ammonia and nitrite oxidation and in carbon dioxide respiration rate. Interestingly, mixing of the growing media constituents resulted in a stimulation of the function of the microorganisms. The use of organic fertilizer resulted in an increase in amoA gene copy number by factor 100 compared to inorganic fertilizers. Our results support our hypothesis that the activity of the functional microbial community with respect to nitrogen turnover in an organic growing medium can be improved by selecting and mixing the appropriate growing media components with each other. These findings contribute to the understanding of the functional microbial community in growing media and its potential role towards a more responsible horticulture

Storage, fertilization and cost properties highlight the potential of dried microbial biomass as organic fertilizer

The transition to sustainable agriculture and horticulture is a societal challenge of global importance. Fertilization with a minimum impact on the environment can facilitate this. Organic fertilizers can play an important role, given their typical release pattern and production through resource recovery. Microbial fertilizers (MFs) constitute an emerging class of organic fertilizers and consist of dried microbial biomass, for instance produced on effluents from the food and beverage industry. In this study, three groups of organisms were tested as MFs: a high-rate consortium aerobic bacteria (CAB), the microalgaArthrospira platensis('Spirulina') and a purple non-sulfur bacterium (PNSB)Rhodobactersp. During storage as dry products, the MFs showed light hygroscopic activity, but the mineral and organic fractions remained stable over a storage period of 91 days. For biological tests, a reference organic fertilizer (ROF) was used as positive control, and a commercial organic growing medium (GM) as substrate. The mineralization patterns without and with plants were similar for all MFs and ROF, with more than 70% of the organic nitrogen mineralized in 77 days. In a first fertilization trial with parsley, all MFs showed equal performance compared to ROF, and the plant fresh weight was even higher with CAB fertilization. CAB was subsequently used in a follow-up trial with petunia and resulted in elevated plant height, comparable chlorophyll content and a higher amount of flowers compared to ROF. Finally, a cost estimation for packed GM with supplemented fertilizer indicated that CAB and a blend of CAB/PNSB (85%/15%) were most cost competitive, with an increase of 6% and 7% in cost compared to ROF. In conclusion, as bio-based fertilizers, MFs have the potential to contribute to sustainable plant nutrition, performing as good as a commercially available organic fertilizer, and to a circular economy

Psychological Determinants of Consumer Acceptance of Personalised Nutrition in 9 European Countries

YesObjective: To develop a model of the psychological factors which predict people’s intention to adopt personalised nutrition. Potential determinants of adoption included perceived risk and benefit, perceived self-efficacy, internal locus of control and health commitment. Methods: A questionnaire, developed from exploratory study data and the existing theoretical literature, and including validated psychological scales was administered to N = 9381 participants from 9 European countries (Germany, Greece, Ireland, Poland, Portugal, Spain, the Netherlands, the UK, and Norway). Results: Structural equation modelling indicated that the greater participants’ perceived benefits to be associated with personalised nutrition, the more positive their attitudes were towards personalised nutrition, and the greater their intention to adopt it. Higher levels of nutrition self-efficacy were related to more positive attitudes towards, and a greater expressed intention to adopt, personalised nutrition. Other constructs positively impacting attitudes towards personalised nutrition included more positive perceptions of the efficacy of regulatory control to protect consumers (e.g. in relation to personal data protection), higher self-reported internal health locus of control, and health commitment. Although higher perceived risk had a negative relationship with attitude and an inverse relationship with perceived benefit, its effects on attitude and intention to adopt personalised nutrition was less influential than perceived benefit. The model was stable across the different European countries, suggesting that psychological factors determining adoption of personalised nutrition have generic applicability across different European countries. Conclusion: The results suggest that transparent provision of information about potential benefits, and protection of consumers’ personal data is important for adoption, delivery of public health benefits, and commercialisation of personalised nutrition.This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement n u 265494 (http://cordis.europa.eu/fp7/home_en.html). Food4Me is the acronym of the project ‘‘Personalised nutrition: an integrated analysis of opportunities and challenges’’ (http://www.food4me.org/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Purple non‐sulphur bacteria and plant production: benefits for fertilization, stress resistance and the environment

Purple non-sulphur bacteria (PNSB) are phototrophic microorganisms, which increasingly gain attention in plant production due to their ability to produce and accumulate high-value compounds that are benefi- cial for plant growth. Remarkable features of PNSB include the accumulation of polyphosphate, the pro- duction of pigments and vitamins and the production of plant growth-promoting substances (PGPSs). Scattered case studies on the application of PNSB for plant cultivation have been reported for decades, yet a comprehensive overview is lacking. This review highlights the potential of using PNSB in plant pro- duction, with emphasis on three key performanceindicators (KPIs): fertilization, resistance to stress (biotic and abiotic) and environmental benefits. PNSB have the potential to enhance plant growth performance, increase the yield and quality of edible plant biomass, boost the resistance to environmental stresses, bioremediate heavy metals and mitigate greenhouse gas emissions. Here, the mechanisms responsible for these attributes are discussed. A dis- tinction is made between the use of living and dead PNSB cells, where critical interpretation of existing literature revealed the better performance of living cells. Finally, this review presents research gaps that remain yet to be elucidated and proposes a roadmap for future research and implementation paving the way for a more sustainable crop production

Environmentally sustainable food consumption : a review and research agenda from a goal-directed perspective

The challenge of convincing people to change their eating habits toward more environmentally sustainable food consumption (ESFC) patterns is becoming increasingly pressing. Food preferences, choices and eating habits are notoriously hard to change as they are a central aspect of people's lifestyles and their socio-cultural environment. Many people already hold positive attitudes toward sustainable food, but the notable gap between favorable attitudes and actual purchase and consumption of more sustainable food products remains to be bridged. The current work aims to (1) present a comprehensive theoretical framework for future research on ESFC, and (2) highlight behavioral solutions for environmental challenges in the food domain from an interdisciplinary perspective. First, starting from the premise that food consumption is deliberately or unintentionally directed at attaining goals, a goal-directed framework for understanding and influencing ESFC is built. To engage in goal-directed behavior, people typically go through a series of sequential steps. The proposed theoretical framework makes explicit the sequential steps or hurdles that need to be taken for consumers to engage in ESFC. Consumers need to positively value the environment, discern a discrepancy between the desired versus the actual state of the environment, opt for action to reduce the experienced discrepancy, intend to engage in behavior that is expected to bring them closer to the desired end state, and act in accordance with their intention. Second, a critical review of the literature on mechanisms that underlie and explain ESFC (or the lack thereof) in high-income countries is presented and integrated into the goal-directed framework. This contribution thus combines a top-down conceptualization with a bottom-up literature review; it identifies and discusses factors that might hold people back from ESFC and interventions that might promote ESFC; and it reveals knowledge gaps as well as insights on how to encourage both short- and long-term ESFC by confronting extant literature with the theoretical framework. Altogether, the analysis yields a set of 33 future research questions in the interdisciplinary food domain that deserve to be addressed with the aim of fostering ESFC in the short and long term

Evaluating the Fertilising Potential of Blended Recovered Nutrients in Horticultural Growing Medium on Viola x wittrockiana L.

Viola x wittrockiana L. is an ornamental plant in high demand in horticulture. It is becoming more critical for greenhouse growers to focus on sustainable production to enhance plant quality while reducing negative environmental impacts. Therefore, assessing the effect of recycled phosphorous (P) and nitrogen (N) sources on the growth of viola could become very useful for producers in terms of sustainability. This experiment analysed the optimal fertiliser composition to grow viola using recovered fertilisers in a greenhouse trial under controlled conditions. Well-rooted viola plugs were grown in a standard peat-based growing medium. Using recycled sources of P and N as struvite and potassium struvite, ammonium sulphate, and ammonium nitrate, 14 fertiliser blends were prepared, tested, and compared with the slow-release commercial fertiliser Osmocote. Plants treated with ammonium nitrate showed healthy growth and optimal plant N concentrations. In contrast, most blends using the recovered ammonium sulphate resulted in an unacceptable increase of ammonium concentrations in the growing medium. The combination of ammonium sulphate and potassium sulphate caused an increase in the electrical conductivity in the growing medium, negatively affecting plant growth. However, blend 13 containing struvite, ammonium sulphate and potassium struvite expressed the best chemical composition with non-significant differences in the biomass from the positive controls, as it reduced the amount of potassium sulphate needed. Our results indicate that fertiliser blends containing P as struvite, N as ammonium nitrate or reduced amount of ammonium sulphate, and K as potassium struvite can substitute the use of mineral fertiliser blends to grow ornamental plant species as viola

Consumer Perception of Food Quality and Safety in Western Balkan Countries: Evidence from Albania and Kosovo

Domestic food markets are of significant importance to Kosovar and Albanian companies because access to export markets is under-developed, partly as a result of the gaps in food safety and quality standards. Kosovar and Albanian consumers’ use of food safety attributes and their evaluation of the quality of domestic food versus imported food are the research objectives of this study. The paper is based on a structured consumer survey of 300 Kosovars and 349 Albanians analyzing their perceptions of issues related to food safety and quality, measured through two respective batteries of items using a 5-point Likert scale. We used the t-test to identify differences between populations, correlation analysis and the bootstrapping method. Despite the prevalent problems with food safety, consumers in both countries consider domestic food to be safer as well as of higher quality than imported products. Kosovars are more likely than Albanians to perceive domestic food products to be significantly better than imported products. Female and better educated consumers use information related to food safety more often. Expiry date, domestic and local origin, and brand reputation are the most frequently used safety and quality cues for both samples. International food standards such as ISO or HACCP are less frequently used as quality cues by these consumer groups. It is important to strengthen the institutional framework related to food safety and quality following best practices from EU countries