Les pratiques agricoles intensives de l’agriculture conventionnelle (AC) ont engendré des fuites d’azote dans l’environnement, via la lixiviation du nitrate (NO3-) et les émissions d’oxyde nitreux (N2O). Une hypothèse de ce travail était que l’agriculture biologique (AB) pouvait contribuer à réduire ces fuites. En conséquence, l’objectif principal de cette thèse a été de mesurer et de quantifier ces fuites d’azote à différentes échelles spatiales (processus, exploitation, bassin versant) et dans différentes systèmes de cultures (AB/AC) du bassin de la Seine.A l’échelle d’une exploitation, la rotation AB (7 ans) engendre 28% mois d’émission de N2O et 25% mois de lixiviation de NO3. A l’échelle du processus, la nitrification, la dénitrification et leurs émissions de N2O associées présentent, en fonction d’un gradient de températures (5-45°C), des courbes gaussiennes. De plus, à l’échelle du bassin versant de l’Orgeval, les bilans azotés ont montré que les pratiques de l’AB (mesure préventive) permettent de réduire les pollutions nitriques diffuses sans engendrer une augmentation d’émissions de N2O, ce qui n’est pas le cas lors de la création d’étangs (mesure curative). Enfin dix-huit exploitations agricoles (8 AB, 10 AC) ont été équipés en bougies poreuses dans le bassin de la Seine. A l’échelle de leurs rotations, les concentrations moyennes sont en AB de 10.1 ± 3.4 mg N l-1 et en AC de 16.6 ± 10.3 mg N l-1. Ces concentrations, converties en flux, aboutissent à des quantités d’azote lixivié en AB de 15.3 ± 9.7 kg N ha-1 et en AC de 27 ± 24.7 kg N ha-1 selon différents pôles pédoclimatiques. / In the past decades, intensive conventional farming (CF) has led to nitrogen (N) losses in the environment, due to nitrate (NO3-) leaching and to nitrous oxide (N2O) emissions. We assumed that organic farming (OF) could contribute in reducing these losses. Therefore, the main aim of this PhD study is to measure and quantify N losses in different spatial scales (process, farm, catchment) and different arable cops systems (OF/CF) in the Seine basin.At the farm scale, the OF rotation reduce by 28% N2O emissions and by 25% NO3 leached. At the processes scale, nitrification, denitrification and their N2O emissions associated, according to a range of temperatures (5-45°C) showed Gaussian curves. At the Orgeval basin scale, the N balance showed OF system (a preventive measure) would allow to reduce diffused N pollution without increasing N2O emissions, differently from the implementation of ponds (a curative measure).Finally, 18 arable crop systems (8 OF, 10 CF) have been equipped with ceramic cups in the Seine basin. At the rotation scale, the sub-root concentrations means were 10.1 ± 3.4 mg N l-1 for the OF systems (with alfalfa in the head of the rotation) and 16.6 ± 10.3 mg N l-1 for the CF systems. The sub-root concentrations converted in the N flow led to 15.3 ± 9.7 kg N ha-1 in OF and 27 ± 24.7 kg N ha-1 in CF, depending on farms in different soil and climate conditions.

The stimulus for the development of organic farming in Europe came in 1924, but the important period for the development were 1970's. The beginning of organic farming in the Czech Republic can be considered as year 1988. Since the beginning of 1990's there has been considerable development of organic agriculture in all European countries. In 2010, there operated 218,500 farms across the European Union, while the total area of organically cultivated land covered 9,181,507 hectares, representing 5.10% of the total utilized area of agricultural land in the EU. Of this number, there were 3,515 farms in the Czech Republic, where the organically cultivated area reached 447,821 hectares. According to the action plan for organic farming in the Czech Republic the goal is to achieve 5,800 farms and 650,000 hectares of organic land in 2015. From the above it is clear that the aim of this thesis is to analyse recent developments, current status and prospects of organic farming in the European Union with an emphasis on the Czech Republic.

The aim of this thesis is to perform marketing research of consumer behavior in the market of organic food through the suitably questionnaire. The research focuses on the questions - what is the source of information about organic food, whether and why consumers buy organic food, how often consumers buy organic food, what is the average monthly expenditure for organic food, what is the most popular place for purchasing organic food, what is main critical points in selecting of organic food, which factors are barrier for purchase, etc. The results of the research confirm that organic food is well known for most of consumers, but lower than half of consumers which purchasing it, either because of high cost or because of mistrust.

The goal of this Diploma thesis is to conduct a strategic analysis of the organic farming farm. The work consists of two main parts, a theoretically-methodological and analytical part. The theoretically-methodological part identifies different approaches to strategy and subsequently describes methods of strategic analysis. Findings from the theoretical and methodological parts are applied in the practical part. It consists of the analysis area and analysis of internal resources and capabilities of farm. The analysis shows many opportunities, but also threats around the farm. The analysis of internal resources and capabilities can be used to determine its strengths and weaknesses. These findings are summarized in the SWOT analysis, where they are described in greater detail. The conclusion states strategic recommendations.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES.

The South African Organic farming industry has indicated a stable increase in the production of organic products from insignificant informal sectors to a fast-growing formal sector. Although there is no documented evidence of the origins of the sector, it can be considered that the formalisation of the organic industry started in 1994 with the formation of Organic Agriculture Association of South Africa (OAASA). The expanding organic food sector is a current organisational change in food demand in South Africa. Therefore, it is becoming vital for food marketers to know consumer needs and demands for food in South Africa, particularly organic food, as consumer preferences sturdily affects the direction of the marketers’ approach, in terms of what is in demand and consumed. Accordingly, this research investigated the factors that influence consumer attitude towards organic food and how consumer attitude influences consumers’ buying intentions. A non-experimental quantitative approach was employed to respond to the purpose and goals determined for the study. A survey was circulated to South African purchasers residing in the Gauteng Province, who were over the age of 18 years and liable for their own domestic food acquisitions. A total of 310 questionnaires were completed, but only 301 responses without errors were utilised for statistical analysis. Data collection was conducted by means of an in-store intercept approach and snowball sampling was applied to supplement the purposive sampling approach to achieve a statistically significant respondent sample. In order to examine and understand the socioeconomic characteristics of the sample and further determine the type of respondents who took part in the research, descriptive statistical analysis was used for this current research. Furthermore, to meet the goals of the research, inferential statistical analysis was used to attain the description view of every recognised variable’s performance of the participants. The findings of this research firstly showed that product quality, subjective norms, health and environmental concerns had a positive influence on consumer attitude towards organic food. The analysis further indicated that health concerns had the strongest influence on the respondents’ attitude for organic food, followed by product quality, then subjective norms. Surprisingly, environmental concerns showed no statistically significant influence on the consumers’ attitudes towards the purchase of organic foods. Secondly, the results showed that the respondents had a favourable and positive attitude for organic food. The participants believed that organic food was higher quality, healthier, safer, fresher and tastier than conventionally grown food. Thirdly, the results showed that even though the respondents considered price as a significant influence when purchasing food, and also considered organic foods to be expensive than conventional food products, they still intended to purchase more organic food. The results further showed that, though some respondents had access to organic food in the retail-stores where they regularly shop, other respondents still expressed difficulty in finding organic food products. However, this does not change their intent to purchase more organic food. Lastly, the results indicated that, although respondents had a great intent to buy organic food, this did not translate into actual purchase behaviour, because actual shopping behaviour of organic food was low, which reiterates the intention-behaviour gap. This means that, although the respondents had a strong intention to purchase organic foods, there are still hurdles which hindered them from making the actual buying of organic foods. The intention-behaviour gap among consumers is mostly triggered by the inaccessibility of organic food products, consumers’ lack of confidence in the trustworthiness of organic food certifications, and the high price of organic food. It is therefore advised that organic food sellers must aim to expand purchasers’ awareness of organic food, in terms of what makes organic food distinctive from non-organic food and the justifications for high prices of these products, so they will be more prepared to buy organic food. Organic food traders and marketers must improve the accessibility of these foods by supplying them where it is convenient for purchasers to buy such products. It is also suggested that the South African government must put in place official certification and inspection programmes for organic food products to improve consumer confidence in certified organic food products. This current research can contribute by adding value to the literature on environmental sustainability in the perspective of a growing economy, specifically South Africa. The research further extends its contribution in assisting organic food producers, operations, sellers, government and regulatory institutions to further understand the factors that influence consumer attitude for organic food and consumers’ buying intentions. This will enable the effective development of organic agricultural programmes (e.g. certification) and improve marketing campaigns that will motivate South Africans to select organic food products. / Life and Consumer Sciences / M. Cons. Sci.

Field and lab experiments were conducted to determine the efficacy of sudangrass (Sorghum X drumondii (Nees ex Steud.) Millsp. & Chase) cover crop management techniques and soil solarization on important agricultural weeds and pathogens in organic strawberry production in Central California. Lab experiments assessed the time needed to kill weed seeds at temperatures typically achieved during soil solarization (40°C, 45°C, 50°C, 55°C, and 60°C) in California. Seeds tested included little mallow, redstem filaree, bristly oxtongue, annual sowthistle, common purslane, nettleleaf goosefoot, and redroot pigweed. Efficacy of simulated solarization temperatures differed between different species. Cool-season annuals annual sowthistle and bristly oxtongue were more susceptible to heat treatments than warm-season annuals common purslane, redroot pigweed and nettleleaf goosefoot. Hard seeded weed species little mallow and redstem filaree were the least susceptible to heat treatments. Annual sowthistle, bristly oxtongue and nettleleaf goosefoot were affected at all temperatures. Redroot pigweed and little mallow were not affected by temperatures below 40°C. Common purslane was not affected by temperature below 45°C and redstem filaree was not affect by any temperatures tested. Hours of exposure and percent mortality of weed seeds were used to create thermal death models for weed seeds. Field experiments were conducted at the Cal Poly Organic Farm in San Luis Obispo, CA testing the effects of soil solarization and sudangrass residues on weeds, Verticillium dahliae populations, plant health, and yields in organic strawberry production. Using a split plot design, sudangrass was grown, mowed and then developed into two treatments: surface mulch or incorporated into the soil. The sudangrass treatments and a control were tested with and without soil solarization (n=4). Maximum soil temperatures in solarized treatments were 53°C at a soil depth of 5 cm and 42°C at a soil depth of 15 cm. Solarization reduced weed biomass between 49.8 and 95.2% during the first 3.5 months after tarp removal (p=0.03), reduced Verticillium dahliae populations by 80.7% (p=0.01), reduced plant mortality by 54.9% (pV. dahliae populations (p=0.33) or yields (p=0.25). However, mulched treatments reduced weed biomass between 45.0 and 61.3% (p=0.03) compared to other sudangrass treatments. Results indicate solarization can be used in central coast organic strawberry production to reduce hand-weeding, disease incidence, and increase yields.

The diploma thesis focuses on the comparison of milk quality in two different ways of farming, conventional and organic farming. Almost a hundred parameters on the set of 64 bulk milk samples were monitored. The theoretical part of the paper describes the composition of cow's milk, its technological and hygienic properties and it notes the nutritional impact of milk and milk products. It also mentions the most important legal definition of organic farming. Experimental part describes the setting of the experiment and mentions the methods used to analyze milk samples for individual parameters and it details the ten selected determination. The difference in measured values of various milk indicators depending on the dairy farm was observed by using statistical methods and an explanation was suggested in the case of the statistical significance. The thesis was based on the cooperation of the Faculty of Chemistry VUT Brno and a National reference laboratory for raw milk at the Research Institute for Cattle Breeding in Rapotin.

The focus of this diploma thesis is organic farming. Its goal is to evaluate the positives and the negatives of organic farming from the sustainable development point of view. Sustainable development is usually divided into three pillars - environmental, economic and social. However, this thesis uses the division into four pillars of sustainability, in which the social pillar is divided into socio-political and human pillar, which is more fitting in this case. This division allows a more detailed evaluation of organic farming. The thesis also deals with the question of sustainability of the researched farm in the future. The method chosen for the thesis is a case study, thanks to which a specific case was researched and answers for the stated questions could be found. Rainton farm in the South of Scotland serves as the case for the practical part of the thesis. Since the early 1990s Rainton has been in the process of conversion from the conventional to the organic way of farming. The business has been diversified and therefore the research could be focused also on the development of the visitor centre, ice-cream or cheese making. Thanks to the data from interviews, participant observation and other documents, a complex picture of the organic farm was created. The research has shown that the...

The United Nations organization for food and agriculture argues that humanity hastaken the soils of the world for granted. Due to chemical pollution, erosion,salinization, compaction, and acidification, 33 percent of the soils are moderately orhighly degraded. If humanity loses more productive soils, there is a risk that foodinsecurity and poverty would increase as well as the diminishing of severalecosystem services.This study focuses on the anthropogenic external factors that affect the agriculturalfields since the conventional and organic farmers use different methods relating tofertilizers, manure, and pesticides. A comparison of soil organic matter between soilsamples from organic and conventional farms in Sweden was carried out, throughsoil sampling and then analyzed with the combustion method. The study alsoevaluates the effect of erosion on the fields in the sampling region.According to this study’s results, there is no significant difference between theamount of soil organic matter in conventional or organic farming soil in southeastSweden, and there has been no erosion on the fields in the past seven years since theSOM content had neither increased nor decreased. This knowledge can be of furtheruse in soil science studies.