The sustainable use of the environment for agriculture has become a global priority, requiring urgent solutions in view of intensifying competition. The South African government and the agricultural sector drafted a strategic plan for South African Agriculture. In this plan it was argued that the potential for the horizontal expansion of agricultural production is limited with one of the limitations being that unused high and medium potential land is scarce. This implies that the challenge for higher agricultural production is immense because primarily it would have to come from increased efficiency. All businesses are confronted by change at some time in their history in which agribusiness in South Africa has been subjected to changes in its past. In this era of hyper competition, agribusinesses are faced with constant change. It is how businesses deal with that change that will determine how successful they will remain in the future. The main problem of this research was to determine if farmers in the Great-Kei Region have the appropriate strategies in place to manage environmental constraints effectively. Therefore, the identification and isolation of prominent environmental constraints, through literature review and survey data gathered and analysed, would assist agribusinesses in the planning and prioritising of investments. The investment would be aimed at facilitating the development and sustainable growth in the Great-Kei Region. In this study, a quantitative, descriptive and non-experimental research design was followed. The target population of the study was farmers with farming businesses operating in the Great-Kei Region. There was data obtained from the Eastern Cape Department of Agriculture provincial office in Komga servicing the Great-Kei Region. The data obtained were lists of registered commercial farmers from the Komga iv Agricultural Association and emerging farmers operation in the region. The data obtained did not include all the farmers operating in the Great-Kei Region. The combined sum of farmers from both lists was 38 farmers (N = 38). The population N = 38 was used as a sampling frame representing the population of farmers in the Great-Kei Region. The population of this study consisted of owners or farm managers running the farming businesses and excludes other farm employees employed at the farms. Farmers with agribusinesses in the area who produced either livestock farming or crop farming or both were included for the study. The results of the survey revealed key findings, which enabled the researcher to draw meaningful conclusions and recommendations. The recommendations suggested how farmers can overcome the identified macro, micro and internal environmental constraints affecting them in the Great-Kei Region. Further identification of strategies currently employed by farmers in managing environmental constraints and the competency levels, indicated where gaps resided with strategies currently employed by farmers and where possible change would be required.

Papago Indian fields located in southern Arizona and northern Sonora, Mexico are examples of a food production strategy that was developed within the constraints of a water-limited environment. Although only a small percentage of the fields cultivated at the turn of the century remain in cultivation, extant fields are vestiges of an agricultural tradition that has persisted in arid lands for centuries. An examination of the documentary history of non-Indian observations of Papago agriculture and water control from 1697 to 1934 reveals numerous practices and features that are no longer apparent within or around remaining fields. Yet by learning from oral historical accounts of elderly Papago, and analyzing O'odham lexemes (native Papago terms) which guide farmers' management of fields, it is possible to gain a sense of folk science which Papago developed to successfully farm without permanent surface water reserves. Selected concepts from the folk science of the Papago are used as a point of departure in understanding the ecological processes which function within their fields. Standard field ecology methods were adapted to empirically test certain hypotheses relating to these ecological processes. Results include confirmation that Papago fields are situated in a variety of physiographic positions, and that ‘ak-ciñ arroyo mouth' farming is a misnomer. Papago crops exhibit many of the same drought-escaping adaptations as wild summer desert ephemerals for seed production during the brief summer rainy season, which varies from year to year in the date of its initiation. These adaptations greatly contribute to crop success. There are no significant differences in the diversity of herbaceous plants found in Papago fields compared to the diversity found in adjacent, uncultivated environments. Of the many nutrients analyzed in cultivated and uncultivated floodplain soils, only potassium was significantly richer in fields than in uncultivated floodplains; other differences were statistically insignificant. Floodwashed organic detritus, rather than the floodwaters themselves, appear to play the major role in renewing field soil fertility in certain localities. It is concluded that indigenous concepts which have long guided the management of traditional agricultural systems are of heuristic value in understanding how these farming systems function ecologically.

La modélisation dans le domaine de l'agro-écologie est importante car elle permet de mieux comprendre les interactions entre l'environnement et les activités humaines. Des travaux basés sur la simulation ont été développés depuis des années. Cependant, non seulement ces outils restent difficiles à utiliser par les utilisateurs non experts, mais aussi le coût des modèles rend leur utilisation difficile à case de la complexité élevée en cas d'application réelle. Nous proposons une approche qui consiste à représenter le système étudié dans un formalisme de système à événements discrets qui est bien adapté quand la dynamique du système est liée à des interactions entre les entités concernés. Ceci permet de profiter l'efficacité du model-checking pour étudier le comportement du système modélisé et d'utiliser la synthèse de contrôleur pour générer automatiquement des stratégies optimales. Nous présentons deux contributions dans cette thèse. La première contribution concerne le projet EcoMata. Cette modélisation qualitative en automates temporisés pour un réseau trophique marin de type proie-prédateur permet d'analyser l'écosystème à l'aide de model-checking sans avoir à faire des simulations. Des scénarios de requête prédéfinis ont été développés dans un langage naturel pour que les utilisateurs non expert puissent faire des requêtes sur les réseaux trophiques sans avoir des connaissances sur la langage TCTL. Nous avons amélioré la génération automatique d'automates temporisés à partir d'une description des équation Lotka-Votera. Nous avons aussi proposé une approche de synthèse de contrôleur pour générer automatiquement des stratégies optimales de gestion de pêche. Le prototype logiciel EcoMata implémente l'ensemble des propositions incluant la recherche de stratégies optimales. Dans la seconde contribution, nous proposons une modélisation hybride en automates temporisés d'une exploitation de pâturage. Cette modélisation hybride combine un modèle numérique de la croissance d'herbe et un modèle qualitatif des activités de pâturage. Une structure hiérarchique organise les modèles dans quatre couches: la couche biologique, la couche activité, la couche décisionnelle et la couche d'horloge. Nous proposons quatre méthodes pour générer des stratégies optimales des activités de pâturage. La première méthode est appliquée à la recherche de stratégies optimales de la mise au pâturage. Trois méthodes sont dédiées à la recherche de stratégies optimales de la fertilisation. Une d'entre elles utilise la synthèse de contrôleur alors que les deux autres combinent la synthèse de contrôleur et l'apprentissage supervisé pour générer des stratégies génériques par type d'exploitation. Un prototype logiciel PaturMata a été développé implémentant cette modélisation, permettant aux utilisateurs de simuler des scénarios de pâturage et rechercher des stratégies optimales de mise au pâturage. / The modeling in the domain of agro-ecology is important since it helps us to better understand the interactiosn between the environment and the human activities. Some research works based on simulation has been carried out during the recent years. Mainwhile, not only these simulation tools are difficult to use by the non expert users, but also the high complexity of models makes interactive uses impossible. We propose an approch in which we represent the system to be studied in a discret event system formalism. This kind of representation benefits the efficiency of model-checking and makes it possible to use controller synthesis to generate strategies. We present two contributions in this thesis. The first one concerns the project EcoMata. This project proposes a qualitative modelling which represents a marine prey-predator type food chain in timed automata. Predifined query patterns in natural langurage are also proposed which allow users to investigate easiy the food chain. We have improved the efficiency of the algorithm of timed automata generation and also developped a strategy synthesis method to generate best fishing management strategy. The prototype software EcoMata implements all these propositions including the best strategy synthesis. In the second contribution, we propose a hybrid modelling which represents grazing activities in timed automata. This hybrid modelling combines a numerical grass model and a qualitative grazing model. These sub models are organized in a hierarchical struture of four layers: the biological layer, the activity layer, the decision layer and the clock. We propose four methods to generate best grazing management strategy. One of these methods is applied to the movement of herd. The other three methods are applied to fertilization among which one of them use controller synthesis on timed automata and the other two combine controller synthesis and machine learning to generate generic strategy for a exploitation type. A prototype software PaturMata has been developped which implements this modelling method and the generation of the best strategy of herd movement.

Orientadora: Neusa Maria Dal Ri / Banca: Júlio César Torres / Banca: Cândido Giraldez Vieitez / Banca: Fabiana de Cássia Rodrigues / Banca: Carlos Bauer de Souza / Resumo: A presente pesquisa teve como objetivo analisar as diretrizes programáticas e a política educacional do MST, a partir da relação que é estabelecida entre o Movimento, a política, a economia e a sociedade. Para isso, identificamos e analisamos os principais objetivos da educação do MST; verificamos a articulação entre as proposições políticas, econômicas e educacionais e, por fim, buscamos desvendar as mudanças ocorridas nas tendências educacionais veiculadas e aplicadas pelo MST a partir de 2000, tendo em vista os dois Encontros Nacionais de Educadores da Reforma Agrária (ENERA) realizados em 1997 e 2015, respectivamente. Outro objetivo que nos debruçamos nesta pesquisa foi compreender a relevância do estudo da educação do MST na atualidade. O Movimento tem sua origem no enfrentamento do avanço histórico do capital no campo. Um dos resultados de sua luta é a organização e desenvolvimento de uma Pedagogia autêntica que tem formado conceitual e politicamente seus militantes para o trabalho, para a vida e, principalmente, para a continuidade da luta do MST. A crise do capitalismo impactou profundamente a configuração societal do mundo contemporâneo. Tratou-se de uma rearticulação política, econômica e social que, no âmbito dos processos de produção, trouxe alterações nas implementações de novas tecnologias, tornando a expansão do capital global. O avanço do capital na atualidade no campo é designado de agronegócio. Contra esse modelo, o MST, desde 2014, passou a defender, por me... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The present research had as a goal to analyze the programmatic directives and the educational politics of the MST, from the connexion that is established between the Movement, politics, economy and society. Thus we identified and analyzed the main objectives of MST education; we verified the articulation between the political, economic and educational propositions and, finally, we sought to unveil the changes that have occurred in the educational trends transmitted and applied by the MST since 2000, in light of the two National Meetings of Agrarian Reform Educators (ENERA) held in 1997 and 2015 respectively. Another goal of this research was to understand the relevance of the study of MST education today. The Movement has its origin in confronting the historical advance of capital in the countryside. One of the results of its struggle is the organization and development of an authentic Pedagogy that has conceptually and politically formed its militants for the work, for life and, especially, for the continuity of the struggle of the MST. The crisis of capitalism has profoundly impacted the social configuration of the contemporary world. It was a political, economic and social rearticulation which in the scope of production processes brought changes in the implementations of new technologies, making the expansion of global capital. The current capital advance in the countryside is called agribusiness. Against this model, the MST, since 2014, started to defend, through the Agra... (Complete abstract click electronic access below) / Doutor

Nessa pesquisa buscou-se compreender como o ensino superior em Engenharia Agronômica, na atualidade, contribui para a formação de profissionais capazes de compreender a crise sócio-ambiental da modernidade e suas inter-relações com o sistema produtivo atual e, principalmente, capazes de construir soluções e atuar criticamente para a reversão da mesma. Especificamente, buscou-se analisar a abordagem da agroecologia como saber ambiental nos currículos e projetos pedagógicos dos cursos públicos de Engenharia Agronômica do estado de São Paulo. Esta pesquisa configura-se como exploratória; foram utilizados diferentes instrumentos metodológicos, sendo: análise documental e análise de conteúdo para a revisão das disciplinas obrigatórias e optativas do currículo, análise dos projetos pedagógicos dos cursos e identificação de eventos e grupos de extensão relacionados; entrevistas semiestruturadas aos docentes responsáveis pela disciplina de agroecologia ou similar dentro de cada curso; e questionário estruturado aplicado aos coordenadores de curso, com o objetivo de captar a abordagem institucional da agroecologia nos cursos. Há, por um lado, um discurso institucional de que agroecologia é importante para a formação profissional e, por isso, as instituições de ensino têm incluído este enfoque em seus currículos. Por outro lado, ao dirigirmos o olhar para as atividades acadêmicas principais que constituem a trajetória do estudante de Engenharia Agronômica, detectamos que o discurso institucional nem sempre corresponde à realidade cotidiana do espaço universitário. Há sussurros sobre agroecologia nos currículos, mas claramente os cursos estão muito mais densamente voltados para a reprodução de um modelo de desenvolvimento da agricultura que, a despeito dos sérios problemas sócioambientais por ele gerados, continua a ser alimentado pelas instituições de ensino superior na área de Ciências Agrárias. Entretanto, mesmo contracorrente e numericamente pouco expressivas, há iniciativas bem fundamentadas em torno da área de agroecologia e de áreas direta ou indiretamente relacionadas a ela. O desafio para a inclusão do enfoque agroecológico na formação dos Engenheiros Agrônomos é duplo: tanto promover uma mudança epistemológica dos conceitos tratados quanto uma mudança metodológica, impulsionada pela natureza complexa destes mesmos conceitos. As vozes que ousam aparecer em meio ao silenciamento de grande parte da universidade frente às complexas questões sócio-ambientais da agricultura são vozes que podem reverberar e impulsionar processos de não rendição ao que se aceita como inexoravelmente proposto; essas vozes ganham corpo quando aliadas a outros movimentos e dinâmicas semelhantes em diferentes esferas que transcendem a formação superior, porque a luta pela construção de uma nova racionalidade, no final das contas, é uma só. / In this research sought to understand how higher education in Agronomy, at present, contributes to the formation of professionals capable of understanding the ecological and social crisis of modernity and its interrelations with the current production system, and especially able to build solutions and critically act to reverse it. Specifically, it aimed to examine the approach of agroecology and environmental knowledge in the curriculum and pedagogical projects of the public courses of Agricultural Engineering of São Paulo. This research appears as exploratory; we used different methodological tools, namely: document analysis and content analysis for the revision of compulsory and elective curriculum, analysis of the pedagogical projects and identification of events and related extension groups, interviews semi-structured information for teachers responsible for the discipline of agroecology or similar within each course, and a structured questionnaire applied to the course coordinators, with the aim of capturing the institutional approach of agroecology courses. There is, firstly, that an institutional discourse of agroecology is important for training and therefore the educational institutions have included this approach in their curricula. Moreover, to cast a glance at major academic activities that constitute the trajectory of the student of Agricultural Engineering, we find that the institutional discourse does not always correspond to everyday reality of university space. There are whispers about agroecology in the curricula, but the courses are clearly much more heavily focused on the reproduction of a model of agricultural development that, despite the serious social and environmental problems generated by it, continues to be fueled by higher education institutions in crop science. However, even counter and numerically insignificant number, initiatives are well founded around the area of agroecology and areas directly or indirectly related to it. The challenge for the inclusion of agroecological focus on training of Agricultural Engineers is twofold: to promote both an epistemological change of concepts treated as a methodological change, driven by the complex nature of these same concepts. The voices that dare to appear amid the silence of much of the university in the face of complex socio-environmental issues in agriculture are voices that can reverberate and drive processes not surrender to what is accepted as inexorably proposed, these voices are given shape when combined with other similar dynamic movements and in different spheres that transcend the higher education, because the struggle to build a new rationality, ultimately, is one.

A crescente demanda por batata e outras hortaliças cultivadas organicamente no Brasil representa uma importante oportunidade e um desafio para os produtores orgânicos. Na atualidade, é limitado o esforço de pesquisa enfocando fertilização, adaptação de cultivares e manejo de pragas e doenças para sistemas orgânicos de cultivo da batata. Em geral, a produtividade na produção orgânica de batata é baixa em comparação a obtida no sistema convencional, devido à cultura estar sujeita à inúmeras pragas, doenças e distúrbios fisiológicos. Como não existem no mercado cultivares adaptadas especificamente ao sistema orgânico, os produtores utilizam cultivares européias e norte-americanas desenvolvidas para o sistema convencional de cultivo. O objetivo deste estudo foi avaliar, sob sistema de cultivo orgânico, cultivares nacionais e estrangeiras desenvolvidas para o cultivo convencional, quanto ao potencial produtivo e qualidade, em condições de campo, sujeitas ao ataque de pragas e doenças. Os experimentos foram conduzidos, em 2007 e 2008, em dois locais: a) Estação Experimental Agroecológica do Pólo Regional do Leste Paulista/APTA, em Monte Alegre do Sul - SP, b) Sítio Orgânico Pereiras, em Socorro - SP. O delineamento experimental adotado foi em blocos ao acaso com quatro repetições. Os tratamentos constaram das cultivares Agata, Apuã (IAC-5977), Aracy (IAC-2), Asterix, Caesar, Catucha (Epagri-361), Cupido, Éden, IAC Aracy Ruiva, Itararé (IAC-5986), Melody, Monte Alegre 172, Novella e Vivaldi, além dos clones avançados IAC 6090 (Ibituaçú), APTA 16.5, APTA 15.20 e APTA 21.54. Em cada experimento foram incluídas, pelo menos, 10 cultivares. As demais cultivares e clones avançados foram incluídos, pelo menos, em um experimento. Foram avaliados os seguintes parâmetros: produtividade total e comercial, números total e comercial de tubérculos, teor de matéria seca, açúcares redutores e totais, resistência à requeima (Phytophthora infestans) e à pintapreta (Alternaria solani). Em 2007, em Monte Alegre do Sul, as cultivares Apuã (14,32 t ha-1), Monte Alegre 172 (13,44 t ha-1), e o clone Ibituaçú (12,75 t ha-1) apresentaram os rendimentos mais elevados. No mesmo ano, em Socorro, Ibituaçú (21,27 t ha-1) apresentou o maior rendimento entre os genótipos avaliados. Em 2008, em Monte Alegre do Sul, os clones APTA 16.5 (24,25 t ha-1), APTA 21.54 (23,21 t ha-1) e Ibituaçú (20,19 t ha-1), e as cultivares Cupido (18,03 t ha-1), Apuã (17,08 t ha-1), Itararé (16,66 t ha-1), e Monte Alegre 172 (16,18 t ha-1) mostraram as maiores produtividades. No mesmo ano, em Socorro, APTA 16.5 (21,02 t ha-1), APTA 21.54 (19,28 t ha-1), Ibituaçú (19,88 t ha-1), e Apuã (18,72 t ha-1) mostraram excelente desempenho para rendimento. Os teores de matéria seca e de açúcares redutores para todos os genótipos avaliados mostraram, respectivamente, valores maiores e menores em relação aos encontrados na literatura. APTA 16.5, Apuã, Aracy, Aracy Ruiva, Éden, Ibituaçú e Monte Alegre 172 apresentaram de moderado a elevado nível de tolerância à pinta-preta, apresentando poucos ou ausência de sintomas da doença. Apuã, Aracy, Catucha, Ibituaçú e Monte Alegre 172 mostraram elevado nível de resistência à requeima. / An increasing demand for organic potato and other vegetable crops in Brazil represent a considerable opportunity and a challenge for organic growers. So far, limited research has been conducted on organic potato production in Brazil pertaining to fertilization, cultivar adaptation, and pest management for organic potato systems. Yields in organic potato production are usually lower than in conventional production systems, because the crop is subject to many pests and physiological disorders. Furthermore, potato cultivars adapted to organic systems are unavailable in the market. Thus, European and North American cultivars developed for conventional crops that have high yielding potential and tolerance to the most limiting diseases and physiological disorders are used by the organic growers. The aim of this study was to evaluate under organic production on-farming conditions, potato cultivars bred in Brazil and abroad adapted for conventional growing systems, in terms of yield potential and qualities. The experiments were conducted in 2007 and 2008, in two locations: a) Agro-ecological Experimental Station of the Polo Regional do Leste Paulista/APTA, in Monte Alegre do Sul - SP County; b) Pereiras agro-ecological farm, Socorro-SP County. A randomized block experimental design was adopted with four replicates. The treatments consisted of the cultivars Agata, Apuã (IAC-5977), Aracy (IAC-2), Asterix, Caesar, Catucha (Epagri- 361), Cupido, Éden, IAC Aracy Ruiva, Itararé (IAC-5986), Melody, Monte Alegre 172, Novella, and Vivaldi, in addition to the advanced clones IAC 6090 (Ibituaçú), APTA 16.5, APTA 15.20 and APTA 21.54. In each experiment there were trialed at least 10 cultivars. The other cultivars or advanced clones were included at least in one experiment. The following parameters were evaluated: total and commercial yield, total and commercial number of tubers, dry matter content, reducing and total sugars, severity of potato late blight (Phytophthora infestans) and early blight (Alternaria solani). In 2007, in Monte Alegre do Sul, the cultivars Apuã (14.32 t ha-1), Monte Alegre, 172 (13.44 t ha-1), and Ibituaçú (12.75 t ha-1) displayed the highest yield performance. In the same year, in Socorro, Ibituaçú (21.27 t ha-1) exhibited the highest yield among trialed cultivars. In 2008, in Monte Alegre do Sul the advanced clones APTA 16.5 (24.25 t ha-1), APTA 21.54 (23.21 t ha-1), Ibituaçú (20.19 t ha-1), and cultivars Cupido (18.03 t ha-1), Apuã (17.08 t ha-1), Itararé (16.66 t ha-1), and Monte Alegre 172 (16.18 t ha-1) showed high yielding performance. In the same year, in Socorro, the treatments APTA 16.5 (21.02 t ha-1), APTA 21.54 (19.28 t ha-1), Ibituaçú (19.88 t ha-1), and Apuã (18.72 t ha-1) showed outstanding yield performance. The dry matter and reducing sugars in all genotypes showed higher and lower, respectively, in relation to those found in the literature. APTA 16.5, Apuã, Aracy, Aracy Ruiva, Éden, Ibituaçú and Monte Alegre 172 exhibited moderate to high level of field tolerance to early blight, displaying few or absence of the disease symptoms. ´Apuã, Aracy, Catucha, Ibituaçú and Monte Alegre 172 showed the highest level of resistance to late blight.

A crescente demanda por batata e outras hortaliças cultivadas organicamente no Brasil representa uma importante oportunidade e um desafio para os produtores orgânicos. Na atualidade, é limitado o esforço de pesquisa enfocando fertilização, adaptação de cultivares e manejo de pragas e doenças para sistemas orgânicos de cultivo da batata. Em geral, a produtividade na produção orgânica de batata é baixa em comparação a obtida no sistema convencional, devido à cultura estar sujeita à inúmeras pragas, doenças e distúrbios fisiológicos. Como não existem no mercado cultivares adaptadas especificamente ao sistema orgânico, os produtores utilizam cultivares européias e norte-americanas desenvolvidas para o sistema convencional de cultivo. O objetivo deste estudo foi avaliar, sob sistema de cultivo orgânico, cultivares nacionais e estrangeiras desenvolvidas para o cultivo convencional, quanto ao potencial produtivo e qualidade, em condições de campo, sujeitas ao ataque de pragas e doenças. Os experimentos foram conduzidos, em 2007 e 2008, em dois locais: a) Estação Experimental Agroecológica do Pólo Regional do Leste Paulista/APTA, em Monte Alegre do Sul - SP, b) Sítio Orgânico Pereiras, em Socorro - SP. O delineamento experimental adotado foi em blocos ao acaso com quatro repetições. Os tratamentos constaram das cultivares Agata, Apuã (IAC-5977), Aracy (IAC-2), Asterix, Caesar, Catucha (Epagri-361), Cupido, Éden, IAC Aracy Ruiva, Itararé (IAC-5986), Melody, Monte Alegre 172, Novella e Vivaldi, além dos clones avançados IAC 6090 (Ibituaçú), APTA 16.5, APTA 15.20 e APTA 21.54. Em cada experimento foram incluídas, pelo menos, 10 cultivares. As demais cultivares e clones avançados foram incluídos, pelo menos, em um experimento. Foram avaliados os seguintes parâmetros: produtividade total e comercial, números total e comercial de tubérculos, teor de matéria seca, açúcares redutores e totais, resistência à requeima (Phytophthora infestans) e à pintapreta (Alternaria solani). Em 2007, em Monte Alegre do Sul, as cultivares Apuã (14,32 t ha-1), Monte Alegre 172 (13,44 t ha-1), e o clone Ibituaçú (12,75 t ha-1) apresentaram os rendimentos mais elevados. No mesmo ano, em Socorro, Ibituaçú (21,27 t ha-1) apresentou o maior rendimento entre os genótipos avaliados. Em 2008, em Monte Alegre do Sul, os clones APTA 16.5 (24,25 t ha-1), APTA 21.54 (23,21 t ha-1) e Ibituaçú (20,19 t ha-1), e as cultivares Cupido (18,03 t ha-1), Apuã (17,08 t ha-1), Itararé (16,66 t ha-1), e Monte Alegre 172 (16,18 t ha-1) mostraram as maiores produtividades. No mesmo ano, em Socorro, APTA 16.5 (21,02 t ha-1), APTA 21.54 (19,28 t ha-1), Ibituaçú (19,88 t ha-1), e Apuã (18,72 t ha-1) mostraram excelente desempenho para rendimento. Os teores de matéria seca e de açúcares redutores para todos os genótipos avaliados mostraram, respectivamente, valores maiores e menores em relação aos encontrados na literatura. APTA 16.5, Apuã, Aracy, Aracy Ruiva, Éden, Ibituaçú e Monte Alegre 172 apresentaram de moderado a elevado nível de tolerância à pinta-preta, apresentando poucos ou ausência de sintomas da doença. Apuã, Aracy, Catucha, Ibituaçú e Monte Alegre 172 mostraram elevado nível de resistência à requeima. / An increasing demand for organic potato and other vegetable crops in Brazil represent a considerable opportunity and a challenge for organic growers. So far, limited research has been conducted on organic potato production in Brazil pertaining to fertilization, cultivar adaptation, and pest management for organic potato systems. Yields in organic potato production are usually lower than in conventional production systems, because the crop is subject to many pests and physiological disorders. Furthermore, potato cultivars adapted to organic systems are unavailable in the market. Thus, European and North American cultivars developed for conventional crops that have high yielding potential and tolerance to the most limiting diseases and physiological disorders are used by the organic growers. The aim of this study was to evaluate under organic production on-farming conditions, potato cultivars bred in Brazil and abroad adapted for conventional growing systems, in terms of yield potential and qualities. The experiments were conducted in 2007 and 2008, in two locations: a) Agro-ecological Experimental Station of the Polo Regional do Leste Paulista/APTA, in Monte Alegre do Sul - SP County; b) Pereiras agro-ecological farm, Socorro-SP County. A randomized block experimental design was adopted with four replicates. The treatments consisted of the cultivars Agata, Apuã (IAC-5977), Aracy (IAC-2), Asterix, Caesar, Catucha (Epagri- 361), Cupido, Éden, IAC Aracy Ruiva, Itararé (IAC-5986), Melody, Monte Alegre 172, Novella, and Vivaldi, in addition to the advanced clones IAC 6090 (Ibituaçú), APTA 16.5, APTA 15.20 and APTA 21.54. In each experiment there were trialed at least 10 cultivars. The other cultivars or advanced clones were included at least in one experiment. The following parameters were evaluated: total and commercial yield, total and commercial number of tubers, dry matter content, reducing and total sugars, severity of potato late blight (Phytophthora infestans) and early blight (Alternaria solani). In 2007, in Monte Alegre do Sul, the cultivars Apuã (14.32 t ha-1), Monte Alegre, 172 (13.44 t ha-1), and Ibituaçú (12.75 t ha-1) displayed the highest yield performance. In the same year, in Socorro, Ibituaçú (21.27 t ha-1) exhibited the highest yield among trialed cultivars. In 2008, in Monte Alegre do Sul the advanced clones APTA 16.5 (24.25 t ha-1), APTA 21.54 (23.21 t ha-1), Ibituaçú (20.19 t ha-1), and cultivars Cupido (18.03 t ha-1), Apuã (17.08 t ha-1), Itararé (16.66 t ha-1), and Monte Alegre 172 (16.18 t ha-1) showed high yielding performance. In the same year, in Socorro, the treatments APTA 16.5 (21.02 t ha-1), APTA 21.54 (19.28 t ha-1), Ibituaçú (19.88 t ha-1), and Apuã (18.72 t ha-1) showed outstanding yield performance. The dry matter and reducing sugars in all genotypes showed higher and lower, respectively, in relation to those found in the literature. APTA 16.5, Apuã, Aracy, Aracy Ruiva, Éden, Ibituaçú and Monte Alegre 172 exhibited moderate to high level of field tolerance to early blight, displaying few or absence of the disease symptoms. ´Apuã, Aracy, Catucha, Ibituaçú and Monte Alegre 172 showed the highest level of resistance to late blight.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Para avaliar a percepÃÃo dos/as agricultores/as quanto Ãs mudanÃas em seus sistemas de produÃÃo e alguns indicadores destas, o presente trabalho foi desenvolvido com agricultores/as adotantes de sistemas de produÃÃo de algodÃo em bases agroecolÃgicas no semi-Ãrido cearense. A proposta de produÃÃo do algodoeiro nas bases comentadas tem a efetiva participaÃÃo dos/as agricultores/as em todo o processo e busca a sustentabilidade ecolÃgica dos sistemas, por meio de prÃticas que mantenham ou recuperem as fertilidades fÃsica, quÃmica e biolÃgica do solo. A identificaÃÃo de indicadores foi feita atravÃs do diagnÃstico participativo envolvendo agricultores dos municÃpios de TauÃ, Chorà e MassapÃ. Os indicadores selecionados foram os de qualidade quÃmica: carbono orgÃnico total (COT), taxa de estratificaÃÃo do COT, teores mÃdios de Ca2+, Mg2+ e K+ trocÃveis, fÃsforo (P) disponÃvel, capacidade de troca catiÃnica (CTC) e valores de pH do solo; os de qualidade fÃsica: densidade do solo, macro e microporosidade e retenÃÃo de umidade; e os de qualidade biolÃgica: diversidade, abundÃncia, riqueza, Ãndices de Shannon e de Pielou da fauna epigeÃca do solo. Para testÃ-los, foram avaliadas quatro Ãreas a saber: duas sob sistema de produÃÃo em bases agroecolÃgicas pertencentes aos agricultores Josà Eduardo Sobrinho (JESA) e Raimundo Valentim de Sousa (RVSA) e duas outras Ãreas, sendo uma sob vegetaÃÃo natural (JESN) e outra sob cultivo tradicional (RVST), tambÃm dos mesmos agricultores citados e na seqÃÃncia respectiva. Essas Ãreas estÃo localizadas no municÃpio de Tauà â CE. Com os resultados obtidos, concluiu que os/as agricultores/as que adotam os sistemas de produÃÃo em bases agroecolÃgicas sÃo capazes de identificar indicadores de sustentabilidade em suas Ãreas nos diferentes aspectos considerados no contexto de sustentabilidade â solo (ambiental), social e econÃmico, e que as qualidades quÃmica, fÃsica e biolÃgica do solo da Ãrea JESA foram superiores as da Ãrea JESN. Por outro lado, as qualidades quÃmica, fÃsica e biolÃgica das Ãreas RVSA e RVST, foram semelhantes. / To evaluate the farmerâs perception about the changes in their systems and in some production pointers, the present work was developed with farmers that adopt cotton production systems in agroecolÃgicas bases at the Cearà state semiarid. The cotton plant production proposal in the commented bases has the effective participation of farmers in the whole process and try to find the ecological support of the systems by means of practice that keep or recover the physical, chemical and biological ground fertilities. The pointers identification diagnosis was made with the participation of agriculturists in the cities of TauÃ, Chorà and MassapÃ. The selected pointers were chemical quality: total organic carbon (COT), stratification rate of the COT, exchangeable average rates of Ca2+, Mg2+, K+, available phosphorus (P), cationic exchange capacity (CTC) and pH values of the ground; physical quality: ground density, macro and microporosity, and humidity retention; and biological quality: diversity, abundance, richness, Shannon and Pielouâs indices of ground epigenetic fauna. Four areas were evaluated to test them: two under system of production in agroecolÃgicas bases belonging to the agriculturists Josà Eduardo Sobrinho (JESA) and Raimundo Valentim de Sousa (RVSA) and two other areas, being one under natural vegetation (JESN) and another one under traditional culture (RVST) belonging respectively to the same agriculturists. These areas are located in the city of TauÃ, CearÃ. With the achieved results, one has concluded that farmers that adopt the production systems in agroecolÃgicas bases are capable to identify supportive pointers in its areas at different aspects considered in the context of support â ground (ambient), social and economic, and that the chemical, physical and biological qualities of the ground in the area JESA have been superior than in the area JESN. On the other hand, the chemical, physical and biological qualities in the areas RVSA and RVST were similar.

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, Diss--Univ. Stuttgart-Hohenheim, 2006. / Literaturverzeichnis S. [291] - 300.