The goal of this thesis is to give an insight in the legislation of the organic farming in the Czech Republic. The thesis is divided into four main parts. The first part presents an introduction to the topic, defines basic concepts such as sustainable agriculture, organic farming, organic farm or organic product. It outlines the historical development of organic farming, its basic principles and objectives, it also deals with genetic engineering and the reasons why they are not used in organic farming, and finally the relationship between organic farming and the protection of individual components of the environment. The second part describes the international regulation of organic agriculture, emphasis is placed on the Convention on Biological Diversity, the International Federation of Organic Agricultural Movements and Codex Alimentarius. The aim is to outline activities of the most important organizations, which were at the beginning of the development of organic agriculture in the world and in the Czech Republic, and which significantly contributed to designing the guidelines and the first laws governing organic farming and they are, in my opinion, up to the present day in a position where they not only can continue to intervene in the rulemaking but also given the gained experince they are supposed and...

Diploma thesis "New forms of distribution and sales of food with a focus on internet trading" aims to analyze the food market to recommend real realization of the new forms of food sales with the focus on the internet usage. The first part is focused on theoretical knowledge that explains the basic concepts related to the topic. In the second part, I focused on questioning and interviews. The aim was to find out if the customers buying food via Internet, whether they would welcome this form of selling and distributing food and the benefits of buying them over the Internet.

Les lombriciens remplissent, dans les agrosystèmes, de nombreux services, importants pour la production et le bon fonctionnement du sol. Cependant, on manque de connaissances sur la manière dont les facteurs jouent, au champ, sur la densité et la diversité spécifique. Cela rend difficile la prévision des effets des pratiques sur la macrofaune du sol et la mise au point de systèmes de culture en Agriculture Biologique, favorables aux populations de vers endogés.L'objectif de cette thèse était d'analyser, au champ, les variations au cours de l'année de l'abondance des lombriciens dans le contexte de l'Agriculture Biologique du Bassin Parisien. Nous nous sommes tout particulièrement interessés au cas des espèces endogées dont nous avons suivi les abondances dans 5 parcelles pendant 2 ans (2009 et 2010). L'analyse de ces données (et de la littérature scientifique) nous a amené à proposer un modèle simulant la dynamique des populations de vers de l'espèce la plus fréquemment rencontrée sur ces parcelles, A. Caliginosa. Ce modèle est basé sur celui de C. Pelosi (Pelosi et al., 2008).L'analyse des données de suivi des populations a montré qu'il existait un schéma général décrivant l'évolution annuelle de l'abondance (i.e. la densité de vers endogés actifs dans la couche 0-30 cm) de ces parcelles labourées et cultivées en céréales. Ce schéma général est caractérisé par une première phase de décroissance (ou de stabilité) en fin de printemps, suivie d'une période estivale pendant laquelle la population est stable, avant d'augmenter à nouveau à l'automne, pour atteindre un niveau maximal supérieur à celui de l'entrée de l'été. Enfin, l'hiver, l'abondance chute à nouveau. Ce travail, qui confirme les données générales de la littérature sur les endogés, a cependant montré que par rapport à ce schéma il existait d'importantes variations d'une année sur l'autre, entre A. caliginosa et A. rosea et en fonction des parcelles. Les causes de ces variations, complexes, sont discutées dans cette thèse.Parmi ces causes, le travail du sol, et tout particulièrement le labour, joue un rôle important. Cela nous a amené à mettre en place un essai, sur deux des parcelles du suivi, pour étudier les effets de cette opération sur la dynamique des populations des deux espèces endogées citées ci-dessus. Les résultats obtenus suggèrent que les effets du labour sont variables en fonction de l'espèce considérée. A. caliginosa s'est révélée plus sensible qu'A. rosea, dont les abondances n'ont pas été systématiquement affectées. Celles d'A. caliginosa ont été réduites, juste après le labour en 2009, avec un certain retard (deux mois environ) après cette opération. Ces résultats soulignent ainsi la nécessité d'étudier l'effet des techniques culturales à travers leur impact sur la dynamique des populations (et non sur le niveau d'abondance moyen).La troisième partie de notre travail a été consacrée à l'amélioration du modèle Wormdyn. Nous l'avons tout d'abord adapté au cas de l'espèce A. caliginosa en nous basant sur une étude bibliographique approfondie pour fixer la valeur des paramètres du cycle de vie. Nous avons ensuite introduit une fonction décrivant l'effet de la densité dépendance sur l'abondance. Le modèle a correctement simulé le niveau moyen des abondances mesurées dans les parcelles suivies, malgré une tendance générale à la surestimation des effectifs lorsque les conditions du milieu sont favorables. L'ajout de la densité dépendance a corrigé partiellement ce biais et ouvre à la prise en compte d'autres facteurs de variation des populations, au premier rang desquels la qualité et la quantité des ressources trophiques. / The earthworms fulfil, in the agroecosystems, many services, crucial for the production and proper functioning of the soil. Therefore, it is necessary to deepen our understanding of the drivers of the changes with time of the density and the specific diversity of earthworms communities. Indeed such a knowledge is necessary to predict the effects of the agricultural practices on soil macrofauna and to design cropping systems in organic farming, beneficial to the earthworm abundance. The purpose of this PhD thesis was to analyse, in agricultural fields, the annual variations of the earthworm abundances in the organic farming context of Northern France. We focused on endogeics species, whose abundance was measured during two years (2009 and 2010) in five cropped fields. A model, simulating the earthworm population dynamics of the most abundant species in our cropped fields, A. caliginosa was parametrised with the data collected in thosse fields (and the bibliography). It was also inspired by Pelosi's model (Pelosi et al., 2008). The analysis of the populations dynamics showed a general scheme describing the annual evolution of the abundance (i.e. active endogeic earthworms in the 0-30 cm layer) of these ploughed fields, cropped with cereals. This scheme is characterized by a four-step evolution. a decrease in the abundance (or a stability) at the end of the spring, followed by a summer period with a stability of the population, before an increase at fall, where the abundance reached a higher level compared to the end of spring. Lastly, in winter, the abundance decreases again. This study, which confirmed the general data given by the literature, revealed also significant variations from one year to the other, between A. caliginosa and A. rosea, and also as a function of the crop field. The causes of these variations are discussed in this PhD thesis. Among the possible causes of these variations, soil tillage, especially ploughing, played an important role. This led us to carry out an experiment to study the effects of this practice on the population dynamics of the two endogeic species mentionned above. The results obtained suggested that the effects of the ploughing was species dependent. A. caliginosa was more sensitive than A. rosea, whose abundances were not systematically affected by the ploughing. Those of A. caliginosa were reduced immediately after ploughing in 2009, with some delay (about two months) after this operation. These results emphasize the necessity to study the effect of the agricultural practices through their impact on population dynamics (and not only through the average level of abundance). The third part of our work was devoted to the improvement of the model Wormdyn. We first adapted the model to the species A. caliginosa based on a literature review to determine the the life cycle parameter values for this species. A function describing the effect of density dependence on the abundance was also introduced in the model. The model correctly simulated the average abundances measured in the cropped fields, despite a general tendency to overestimate the abundances, when environmental conditions are favorable. This was only partially corrected by the addition of the density dependence function. The model has to be improved by the introduction of the effect of other factors, first and foremost the quality and quantity of trophic resources.

Cette thèse analyse à la fois théoriquement et empiriquement certaines des questions qui se posent lors de l'utilisation de politiques environnementales dans le secteur agricole, en situation de commerce. Dans une première partie, l'attention est portée sur la biodiversité des cultures, reconnue pour stabiliser la productivité agricole sous différentes conditions environnementales. Le chapitre II confirme empiriquement cet impact positif en utilisant une large base de données sur l'agriculture sud-africaine. Il montre aussi que la biodiversité peut réduire l'exposition des agriculteurs aux risques de production, en particulier ceux à la baisse. La biodiversité des cultures pourrait donc être partie intégrante de politiques agricoles durables. Néanmoins, les interactions entre les effets de cette biodiversité, les politiques environnementales et le commerce sont complexes. En effet, la spécialisation induite par le commerce s'oppose à la biodiversité en réduisant le nombre d'espèces cultivées. La biodiversité influe positivement sur les niveaux de production, entre autre, en améliorant la résistance aux ravageurs. Pour faire face à des attaques plus fréquentes, les agriculteurs utilisent des pesticides. Mais ces derniers ont des impacts négatifs sur l'environnement et la santé humaine et leur utilisation est donc réglementée. Une politique environnementale concernant les pesticides peut ainsi avoir un aspect stratégique: autoriser l'utilisation de plus de pesticides peut permettre de gagner en compétitivité. Le chapitre III représente ces interactions dans un modèle ricardien de commerce. Il montre que, parce que les effets NIMBY sont plus importants que les impacts stratégiques, la politique environnementale est plus stricte en situation de commerce qu'en autarcie. De ce fait, la volatilité de la production agricole est généralement plus élevée en commerce. Cela pourrait en partie expliquer la volatilité de fond observée sur les marchés agricoles, historiquement plus volatiles que ceux des produits manufacturés. Dans une deuxième partie de la thèse, le chapitre IV illustre les effets de fuite que peuvent engendres des politiques environnementales mises en oeuvre unilatéralement. Un modèle d'équilibre général calculable est utilisé pour quantifier les impacts indirects sur l'environnement à l'échelle mondiale d'un accroissement des surfaces dédiées à l'agriculture biologique en Europe. L'agriculture biologique est connue pour ses bénéfices locaux sur l'environnement mais ses rendements sont inférieurs de 25% en moyenne à ceux de l'agriculture conventionnelle. Nous calibrons les technologies de production de l'agriculture biologique avec des données micro-fondées et trouvons qu'utiliser ces techniques sur 20% des surfaces européennes consacrées au mais, colza, tournesol et blé conduit à un choc de productivité négatif. Ce choc a des conséquences sur les marchés mondiaux et induit des déplacements d'offre et de demande. Les changements d'utilisation des sols résultants sont évalués, ainsi que les changements en termes d'émissions de gaz à effet de serre, d'utilisation d'intrants et de biodiversité. Les effets indirects négatifs sur l'environnement semblent limités, sauf en ce qui concerne les émissions de gaz à effet de serre. En ce qui concerne l'utilisation d'intrants et la biodiversité, les résultats montrent que les effets indirects méritent d'être pris en compte dans les analyses de cycle de vie. Ces résultats ne doivent pas être utilisés pour pointer du doigt l'agriculture biologique, mais ils soulèvent quelques questions, en particulier sur la nécessité d'effectuer des analyses d'impact de façon plus systématique, y compris pour les politiques environnementales, et l'importance de la recherche et développement mais également des politiques publiques pour lever les obstacles techniques et économiques à l'augmentation des rendements en agriculture biologique. / This thesis analyses both theoretically and empirically some of the issues that emerge when applying environmental policies to the agricultural sector in a trade context. In a first part, focus is on crop biodiversity, which is known to maintain agricultural productivity under a large range of environmental conditions. Chapter II empirically confirms this positive impact using a large dataset on South African agriculture. It also shows that biodiversity can reduce the exposure of farmers to production risks and downside risks. At a first glance, crop biodiversity could therefore be integrated in sustainable agricultural policies. Nevertheless, interactions between crop biodiversity effects, environmental policies and trade are complex. Indeed, specialisation induced by trade plays against biodiversity: the composition effect of trade, following comparative advantages, tends to reduce the number of crops cultivated by a given country. One of the mechanisms through which crop biodiversity improves production stability is by participating in the resilience to pests. Then, to face higher pest attacks, farmers use pesticides. But since pesticides harm environment and human health, governments regulate their use. An environmental policy on pesticides can thus have a strategic aspect: allowing the use of more pesticides can lead to gain larger agricultural market shares. Chapter III represents these interactions in a ricardian trade model. It shows that, because not in my backyard effects are larger than strategic impacts, the optimal environmental policy is more stringent under trade than under autarky. Furthermore, because of this stringency, production volatility is generally higher under trade. This could explain part of the background volatility observed on agricultural markets, which have been historically more volatile than those of manufactured products. In a second part of the thesis, chapter IV illustrates the possible leakage effects of environmental policies implemented unilaterally. A computable general equilibrium model is used to quantify the indirect global environmental impacts of a greening of European agriculture through a large shift to organic farming. Organic farming is known for its local environmental benefits, especially on water and soil quality, biodiversity and greenhouse gas emissions. However, organic yields are on average 25% lower than those of conventional farming. We calibrate organic production technologies using micro-level data and find that using organic production techniques on 20% of the European area cultivated with maize, rapeseed, sunflower and wheat results in a large negative productivity shock. This shock affects global markets and induces production and demand displacements, unless the yield gap is reduced. The resulting land use changes are assessed, as well as the corresponding changes in greenhouse gas emissions, chemical inputs use and biodiversity. The negative indirect effects on the environment appear limited compared to the local benefits of adopting greener forms of agriculture in the EU. However, in the case of greenhouse gases, the indirect emissions more than offset the local benefits of organic agriculture. In the case of chemical pollution and biodiversity, results show that indirect effects deserve to be accounted for in life cycle analyses. These findings should not be used to point a finger on organic farming, a large variety of policies and consumption patterns have greater land use change impacts. Nevertheless, they rise some issues, especially on the need for more systematic sustainability assessments, even for environmental polices, the importance of research and development in organic farming to reduce yield gaps and of public policies to help to remove economic factors that could limit the increase of organic yields, such as the relative cost of production factors.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2018-03-14T18:37:04Z No. of bitstreams: 1 2016 - Elisamara Caldeira do Nascimento.pdf: 1795022 bytes, checksum: f0542dfea7f8bcf0ed2dc8ad2238d37d (MD5) / Made available in DSpace on 2018-03-14T18:37:04Z (GMT). No. of bitstreams: 1 2016 - Elisamara Caldeira do Nascimento.pdf: 1795022 bytes, checksum: f0542dfea7f8bcf0ed2dc8ad2238d37d (MD5) Previous issue date: 2016-08-30 / CAPES / FAPERJ / Interest in organic agriculture has increased due to growing public concern with the quality of the food it consumes, the insecurity caused by rising food crises contamination and also aimed at environmental preservation. Organic agriculture offers numerous environmental advantages compared to conventional agriculture, since it is geared to improving biodiversity, restoring the natural ecological balance, soil conservation and water resources. Therefore, it is important to understand how and if these improvements are occurring in the environment and the soil in which agricultural systems are installed compared to other systems of occupation of areas. The purpose of this study was to evaluate the soil of organic production farms in the municipality of Serop?dica- RJ, belonging to producers of the SerOrg?nico organization, as well as areas of pasture and preserved forest. For this, the work was divided into three chapters. In the first, a questionnaire was applied based on the ministry of agriculture producers notebook for all farmers in the association. It was clear that all producers have a great sense of the importance of producing quality food and they know the main techniques for this purpose. However, the difficulties that pass are the same as those faced by all small brazilian producers are marketing difficulties, lack of access to financial credit and technical assistance. In the second chapter, soil samples were collected for evaluation of fertility, grain size analysis, chemical and grain size fracioanamento organic matter and analysis of bacterial diversity by independent analysis of culture (DGGE). The areas of organic farming showed no soil fertility results that express the positive effects of cropping system. However, the attributes that most affect the fertility of the studied areas are pH, Ca, H + Al, P, Carbon, V%, total clay and degree of flocculation. Fractionation of organic matter showed that the more stable fractions are most related to the C present in the evaluated areas and soil management beneficially altered the structure of bacterial communities. In the third chapter, we evaluated the nutritional value of corn plants and italian style tomato conditioned to different commercial inputs of phosphorus and potassium base allowed for organic production system. Both P sources, as for sources of K, did not contribute to differences in the accumulation of dry matter and nutrients in plants of tomatoes and corn, however the italian-type tomato productivity averages were higher than 44 t / ha-1 when treatments they were associated with castor bean, showing that it is a viable alternative sources of fertilizers to organic producers. / O interesse pela agricultura org?nica tem aumentado devido a crescente preocupa??o da popula??o com a qualidade dos alimentos que consome, pela inseguran?a provocada pelas crescentes crises alimentares, por contamina??o e tamb?m visando ? preserva??o ambiental. A agricultura org?nica oferece numerosas vantagens ambientais, comparativamente a agricultura convencional, uma vez que est? orientada para melhoria da biodiversidade, restabelecimento do equil?brio ecol?gico natural, conserva??o dos solos e dos recursos h?dricos. Portanto, ? importante entender como, e se estas melhorias est?o ocorrendo no ambiente e nos solos em que os sistemas agr?colas est?o instalados comparando-se a demais sistemas de ocupa??o das ?reas. A proposta deste estudo foi avaliar os solos das ?reas de produ??o org?nica do munic?pio de Serop?dica- RJ, que pertencem a associa??o de produtores SerOrg?nico, assim como ?reas de pastagem e de mata preservada. Para isto, o trabalho foi dividido em tr?s cap?tulos. No primeiro, foi aplicado um question?rio baseado no Caderno de Produtores do Minist?rio da Agricultura para todos os agricultores da associa??o. Ficou claro que todos os produtores possuem uma grande percep??o da import?ncia de se produzir alimentos de qualidade e que eles conhecem as principais t?cnicas para tal fim. Contudo, as dificuldades pelas quais passam s?o as mesmas enfrentadas por todos os pequenos produtores brasileiros que s?o: dificuldade de comercializa??o, falta de acesso a cr?dito financeiro e assist?ncia t?cnica. No segundo cap?tulo, amostras de solo foram coletadas para avalia??o da fertilidade, an?lise granulom?trica, fracioanamento qu?mico e granulom?trico da mat?ria org?nica e an?lise de diversidade de bact?rias por an?lise independente de cultivo (DGGE). As ?reas de agricultura org?nica n?o apresentaram resultados de fertilidade do solo que expressam os efeitos positivos do sistema de cultivo. Contudo, os atributos que mais afetam a fertilidade das ?reas estudadas s?o pH, Ca, H+ Al, P, Carbono, V%, Argila Total e Grau de Flocula??o. O fracionamento da mat?ria org?nica demonstrou que as fra??es mais est?veis s?o as que mais se relacionam com o C presente nas ?reas avaliadas e, o manejo do solo alterou beneficamente a estrutura das comunidades bacterianas. J? no terceiro cap?tulo, avaliaram-se os aspectos nutricionais de plantas de milho e tomate do tipo italiano condicionadas a diferentes insumos comerciais a base de f?sforo e pot?ssio permitidos para o Sistema org?nico de produ??o. Tanto as fontes de P, quanto as fontes de K n?o contribu?ram para diferen?as no ac?mulo de mat?ria seca e nutrientes nas plantas de tomates e milho, entretanto as m?dias de produtividade de tomate tipo italiano foram superiores a 44 t/ha-1 quando os tratamentos foram associadas a torta de mamona, mostrando-se estas fontes alternativas vi?veis para aduba??o ao produtor org?nico.

Comment se fabriquent les vocations agrobiologiques ? Si l’émergence, l’institutionnalisation et la transformation de l’agriculture biologique en objet d’action publique laissent à penser qu’un segment professionnel s’autonomise, notre enquête montre que les agriculteurs biologiques ne peuvent entièrement échapper à l’action de la profession et de l’encadrement agricoles ainsi qu’aux systèmes de classement produits par leurs pairs. Derrière l’enjeu technique qui consiste à produire sans intrants de synthèse se jouent en effet des luttes pour définir et contrôler le titre d’agriculteur. Ces luttes se jouent à un niveau institutionnel et interpersonnel et ont pour effet de délimiter les frontières du territoire professionnel. De ce point de vue, la figure de « l’agriculteur professionnel » (pratiquant une agriculture à temps complet, intensive et spécialisée) continue à structurer l’économie morale du groupe professionnel et son segment agrobiologique : la sélection et la hiérarchisation des représentants, des encadrants et des producteurs s’opèrent alors en fonction de leur plus ou moins grand ajustement à cette forme d’agriculture. Dès les années 1950, la sélection des dirigeants agrobiologiques s’opère sur leur acceptation de la division de plus en plus réglée des tâches de représentation, de conception, d’encadrement et de production. C’est ce que nous montrons dans un premier temps à partir de l’analyse des archives de la société Lemaire-Boucher et des archives personnelles de Raoul Lemaire, à la fois producteur, boulanger, entrepreneur, sélectionneur et homme politique. L’homme échoue dans sa croisade morale en faveur de l’agriculture biologique précisément parce qu’il se situe à l’intersection d’espaces occupés par des agents de plus en plus spécialisés. À partir d’entretiens semi-directifs, d’observations directes et d’un questionnaire auprès du personnel scientifique et technique participant au contrôle des vocations agrobiologiques, nous analysons ensuite ce contrôle, qui s’opère à bas bruit et de manière indirecte depuis les années 1980. La focale portée sur le processus d’institutionnalisation du segment et sur les logiques de recrutement et de travail des agents d’encadrement permet de montrer que la sélection des agriculteurs biologiques s’opère d’abord par la sélection de ceux qui les sélectionnent. De ce point de vue, l’émergence d’une nouvelle forme d’agriculture n’entraîne pas mécaniquement l’émergence d’un espace d’encadrement autonome : d’un côté, la construction de l’agriculture biologique comme objet de recherche légitime contribue à isoler les chercheurs des agriculteurs — et donc à renforcer les effets du processus de professionnalisation — ; d’un autre côté, l’institutionnalisation de l’agriculture biologique contribue à la naissance d’un appareil d’encadrement dual reposant sur une division morale du travail, entre des organisations et agents d’encadrement favorisant la reproduction de la figure de l’agriculteur professionnel et d’autres dont l’action consiste à ménager des espaces où l’hétérodoxie reste possible.Le contrôle des vocations agrobiologiques s’opère aussi entre agriculteurs, comme l’analyse la troisième partie, basée sur une enquête à dominante ethnographique en Midi-Pyrénées. Nous y montrons que les coûts d’entrée, de sortie et de maintien en agriculture biologique sont différenciés selon l’origine et la trajectoire sociales des agriculteurs, mais également selon la valeur de leur patrimoine de ressources au sein du groupe professionnel agricole. Tant leurs choix professionnels que leur style de vie sont évalués à l’aune de l’idéal modernisateur et professionnel de l’après-guerre. Dès lors, l’origine agricole, le capital symbolique procuré par le diplôme d’agronome, les ressources d’autochtonie, le capital économique et le patrimoine sont autant de ressources qui permettent à certains agriculteurs biologiques d’être considérés comme de « bons professionnels ». / How does one get into organic farming? Even though it has gained its autonomy as a segment, organic farming is not free from the structural constraints imposed to farmers as an occupational group. To produce food without any pesticides is not only a technical matter. Behind that lies a struggle to define and control who is licensed to be a farmer. This struggle takes place both at an institutional and interpersonal level and revolves around the definition of farming. In that matter, the definition inherited from the “modernisation” period (from the 1950s onwards) still has consequences on the way farmers are selected, on the way extension services work and on the way farmers are represented by professional organisations. Our main aim is therefore to understand the effects of “professional farming” on the way people come to organic farming, practice it and talk about it, and on how it creates social and professional differentiation between organic farmers. First, we consider the effects of this new moral economy on the way organic farmers are represented. By analysing the archives of Raoul Lemaire, one of the first advocate of organic farming in France, we show that his moral crusade to represent small scale farmers – and organic farmers in particular – doesn’t succeed because the personal domination he wants to build his power on tends to be replaced by a less personal and more bureaucratic domination embodied by “la profession” : therefore, organic farming lacks visibility from the very beginning of its existence in France in the end of the 1950s. Then, relying on semi-structured interviews and on a survey, we emphasize that the institutional control of who is allowed to be an organic farmer doesn’t depend entirely on organic organisations. By focusing on the way people are recruited and work in specialised and non-specialised research and extension organisations, we show that the selection of the people who select farmers is paramount in reproducing the definition of the occupational territory inherited from the “modernisers”. Finally, relying on qualitative material (observations and semi-structured interviews mainly), we show that there are multiple ways to get into organic farming but also unequal means to resist to the modernisers’ moral economy: thus, being from a farmer’s background and/or being trained as an agronomist and/or having local social capital tend to differentiate some organic farmers form others. Therefore, the technical and symbolic unification of the farming occupational group that took place after 1945, still has important effects on the way the group, the organic segment and rural areas more generally are socially stratified.

Dans une situation de forte vulnérabilité induite par les crises laitières de 2009 et 2014-2016, de nombreux éleveurs laitiers se convertissent à l’AB qui semble une alternative prometteuse. Mais la conversion à l’AB est une période de changements de pratiques agricoles, d'interlocuteurs de conseil, etc. sources d’incertitudes sans valorisation immédiate du lait au prix du lait AB avant 1 an ½ à 2 ans. Ce choix de conversion pose la question de la vulnérabilité des exploitations laitières, c’est à dire de leur capacité à faire face, à s’adapter ou à se remettre des effets de divers aléas avant, pendant et à l’issue de la conversion à l’AB. Ma thèse visait à évaluer si la conversion à l’AB est un moyen de réduire la vulnérabilité des exploitations laitières. Pour ce faire, je me suis appuyée sur trois dispositifs de suivis d’éleveurs laitiers à différents moments de leur conversion à l’AB. Au plan de la production de connaissances, ce travail montre que la conversion à l’AB peut être un levier important pour la réduction de la vulnérabilité des exploitations agricoles à condition de s’orienter vers un système à dominante herbagère. Au plan méthodologique, la principale originalité de mon travail réside dans le développement d’une méthode d’évaluation intégrée et dynamique de la vulnérabilité. / In a situation of high vulnerability induced by the 2009 and 2014-2016 milk crises, many dairy farmers convert to organic farming, which seems a promising alternative. But the conversion to organic farming is a period of changes in farming practices, farm consultants, etc. sources of uncertainties without immediate valuation of the milk at the organic price before 1 ½ to 2 years. This conversion decision raises the question of the vulnerability of dairy farms, i.e. their ability to cope with, adapt to or recover from the effects of various hazards before, during and after the conversion. My PhD project aimed to assess whether the conversion to organic farming is a way to reduce the vulnerability of dairy farms. To that end, my work relied on three research set-ups based on surveys with dairy farmers at different stages of their conversion to organic farming. In terms of knowledge production, this work shows that conversion to organic farming can be an important lever to reduce farms vulnerability, as long as they move towards pasture-based system. In terms of methodological production, the main originality of my work lies in the development of an integrated and dynamic method for vulnerability assessment.

The area of vegetable production is growing rapidly world-wide, as are efforts to increase production on existing lands in these labor- and input-intensive systems. Yet information on nutrient losses, greenhouse gas emissions, and input efficiency is lacking. Sustainable intensification of these systems requires knowing how to optimize nutrient and water inputs to improve yields while minimizing negative environmental consequences. This work characterizes soil nitrogen (N) dynamics, nitrate (NO3¯) leaching, greenhouse gas emissions, and crop yield in five diversified vegetable systems spanning a gradient of intensification that is characterized by inputs, tillage and rotational fallow periods. The study systems included a low input organic system (LI), a mechanized, medium scale organic system (CSA), an organic movable high tunnel system (MOV), a conventional system (CONV) and an organic stationary high tunnel system (HT). In a three-year vegetable crop rotation with three systems (LI, HT and CONV), key N loss pathways varied by system; marked N2O and CO2 losses were observed in the LI system and NO3– leaching was greatest in the CONV system. Yield-scaled global warming potential (GWP) was greater in the LI system compared to HT and CONV, driven by greater greenhouse gas flux and lower yields in the LI system. The field data from CONV system were used to calibrate the Root Zone Water Quality Model version 2 (RZWQM2) and HT and LI vegetable systems were used to validate the model. RZWQM2 simulated soil NO3¯-N content reasonably well in crops grown on bare ground and open field (e.g. beet, collard, bean). Despite use of simultaneous heat and water (SHAW) option in RZWQM2 to incorporate the use of plastic mulch, we were not able to successfully simulate NO3¯-N data. The model simulated cumulative N2O emissions from the CONV vegetable system reasonably well, while the model overestimated N2O emissions in HT and LI systems.

This thesis explores claims that organic agriculture may be an empowering development strategy by investigating the impacts of conversion to organic farming systems on the lives of small-scale farmers in Cambodia. The thesis interrogates the diverse uses and abuses of the term =empowerment‘ in development rhetoric and argues for an empowerment model that is derived from farmers‘ self-defined concepts of development. This model was used to conduct a qualitative case study involving semistructured interviews and focus groups with members of organics initiatives in seven diverse Cambodian communities. Results indicate that many farmers in all communities felt that their most important objective was not only to achieve food security, but to be able to grow sufficient rice to feed their family. Farmers joined the organics initiatives primarily to improve their health and reduce the cost of farming inputs. As a result of joining the initiatives, all farmers (including both certified and non-certified organic farmers) felt they had improved their health and food security. Most farmers also increased incomes, created stronger family and community ties and felt they had more control over their livelihoods. These benefits were not, however, distributed equally amongst individuals or communities. Very poor and isolated farmers could not generally access benefits. The three main factors that determined the impact of the organics initiatives on farmer empowerment were identified as: the individual‘s level of resources, the strength of the farmer group, and the policies and values of the supporting organisation. The implications for future initiatives are, firstly, the tremendous potential for farmers and wider rural communities to benefit from organic agriculture as a development strategy. However, this study also shows that if organics is to be viable for low-resource people, it may be necessary to promote both resources and techniques in organics initiatives. Also, a focus on building strong relationships both within the farmers group and linkages with local and wider stakeholders may enhance long-term sustainability of organics initiatives.

Pomona College is an institution deeply committed to sustainability and student well being; however these commitments are not reflected in the College’s food purchases. Before this study, an assessment of purchasing had not been conducted at Pomona College. Using the Real Food Calculator – a metric designed to evaluate food purchasing at academic institutions – I tracked all food purchased by one of the College’s dining halls over the course of one month. Each food item was assessed based on the potential health concerns of its ingredients and whether the item was locally produced, ecologically sound and/or humane to determine whether it should be considered Real. The assessment metric also lists ingredients with potential health concerns (including trans fats, high fructose corn syrup, MSG, and others), which if present in the food item mean it cannot be considered Real. Of the over $150,000 worth of food purchases made during the study, 8.9% qualified as Real Food. Each food that qualified as Real Food met the standards for at least one of the attributes (local, ecologically sound, or humane). A total of 2.1% of all food purchases qualified for two attributes. Of the foods assessed, over one third contained ingredients considered harmful to human health. If Pomona is serious about its commitments to sustainability and student well being, it is time to include food purchasing in these discussions. The study concludes with a series of recommendations to improve food purchasing at Pomona College.