Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Since 1960s a more pronounced concern for the environmental issues has expressed and susceptible to search for sustainable viable solutions and environmental protection in many countries. Within this context, the family farming manifested as favorable environment, at the socioeconomic level and environment, to the access of sustainability, rural development, food security and the fight against the inland communities poverty. The aim of this research is to analyze the sustainability of family farming in the municipality of Lagarto, Sergipe State. For this aim, was selected the Irrigated Perimeter of Piauí from Lagarto, this locality presents crops and different ways of management. Hence, was relied on the assumption that crop diversification in agriculture tends to contribute to more sustainable systems of both the social, economic and environmental point of view. The study is ruled by theoretical sources that address family farming, sustainable agriculture and the use of indicators for assessing sustainability in agriculture, from the systemic approach. The selection and analysis of indicators were based on |Indicateurs method durabilité des exploitations Agricoles IDEA|, with adaptations, which have identified the main factors that limit the sustainability in family production systems of the study area. As a result it was found that the axis of agricultural sustainability with lower average was the agri-environment, and for which one must seek improvements. Was also identified the low crop diversification in both the conventional system as the organic system, provides lower conditions of financial income in the properties. Thus, it is emphasized that crop diversification in agricultural production systems promotes higher levels of sustainability. / A partir da década de sessenta uma preocupação mais acentuada das questões ambientais tornou suscetível à busca por soluções viáveis de sustentabilidade e proteção ao meio ambiente em diversos países. Neste aspecto, a agricultura familiar manifestou-se como ambiente favorável, tanto em nível socioeconômico quanto ambiental, ao acesso da sustentabilidade, desenvolvimento rural, segurança alimentar e combate à pobreza no campo. O objetivo desta pesquisa foi analisar a sustentabilidade da agricultura familiar no município de Lagarto/SE. Para tanto, selecionou-se o Perímetro Irrigado Piauí no referido município por apresentar plantios e formas de manejo diversificadas. Destarte, apoiou-se na concepção de que a diversificação de cultivos na agricultura tende a contribuir com sistemas mais sustentáveis do ponto de vista social, econômico e ambiental. O estudo foi pautado em referenciais teóricos que abordam a agricultura familiar, agricultura sustentável e o uso de indicadores para a avaliação da sustentabilidade na agricultura, a partir do enfoque sistêmico e em pesquisa de campo. Os indicadores foram selecionados e analisados com base no método Indicateurs de Durabilité des Exploitations Agricoles IDEA, com adaptações, que permitiram identificar os principais fatores que limitam a sustentabilidade nos sistemas de produção familiar da área de estudo. Como resultado detectou-se que o eixo agroambiental contribuiu com a obtenção de menores índices de sustentabilidade, sendo a baixa diversificação de cultivos e a baixa biodiversidade, tanto no sistema convencional quanto no sistema orgânico, os aspectos responsáveis pelas condições mais limitantes nas propriedades afetando a renda financeira dos agricultores. Desta forma, destaca-se que a diversificação de cultivos nos sistemas de produção agrícola promove níveis mais elevados da sustentabilidade.

In dieser Habilitationsschrift werden elf ausgewählte Zeitschriftenartikel vorgestellt. Alle Artikel zielen darauf ab, die Heterogenität der Betriebe des Agrarsektors durch eine bessere Auflösung der Angebotsmodelle zu berücksichtigen. Der erste Abschnitt konzentriert sich auf die Anwendungen mit dem partiellen Gleichgewichtsmodell CAPRI. Der Abschnitt deckt ein breites Spektrum politischer Fragen ab, zum Beispiel, Kopplung bzw. Konvergenz der Direktzahlungen, Ökologisierung, Verringerung der Treibhausgasemissionen und Kohlenstoffsequestrierung. Ich zeige, dass betriebsbezogene Angebotsmodelle eine detailliertere Analyse politischer Auswirkungen ermöglichen. Zudem erlauben diese Angebotsmodelle eine Verknüpfung mit Modellen höherer räumlicher Auflösung. Der zweite Abschnitt befasst sich mit methodischen Fragen zur Schätzung struktureller Veränderungen auf der Ebene der Betriebstypen in einem EU-weiten Ansatz. Der entwickelte Ansatz hilft, Faktoren, die den landwirtschaftlichen Strukturwandel beeinflussen, besser zu bestimmen und bietet die Möglichkeit einer umfassenden Analyse des landwirtschaftlichen Strukturwandels in der EU. Es wird gezeigt, dass die Ergebnisse zum Strukturwandel auch in der Modellierung berücksichtigt werden können. Dafür wurden Methoden entwickelt, die die Wahrung der Konsistenz der regionalen Ebene und die Berücksichtigung von betriebstypspezifischen Bilanzen, Indikatoren und Veränderungen in der Zahl der landwirtschaftlichen Betriebe gewähren. Der letzte Abschnitt befasst sich mit Methoden zur Rückschätzung von zensierten Daten. Ich untersuche verschiedene Datenaggregationsansätze, wie zum Beispiel, ein lokales gewichtetes Durchschnittsverfahren und ein bayesianisches Schätzverfahren, um Parameter für die zensierten Daten zu ermitteln, die der Realität so weit wie möglich entsprechen. / In this habilitation thesis, eleven selected journal articles were presented. All articles aimed to improve the resolution and thus reduce aggregation error to better account for farm heterogeneity in the agricultural sector models. The first section focused on model application with the partial equilibrium model CAPRI at the farm-type level. It covered many policy issues, such as coupling, convergence, greening, GHG mitigation, and carbon sequestration. I demonstrate that the farm-type supply models enable a detailed analysis of various policy impacts. It was demonstrated that the EU's supply models could improve model linkage with higher spatial resolution models, thus further closing the gap with spatial land-use models. The second section addressed significant methodological queries about estimating structural changes at the farm-type level in an EU-wide approach. A regional approach helps to identify better factors affecting agricultural structural change. The approach offers the opportunity for a comprehensive and previously unachievable analysis of agricultural structural change in the EU. Integrating the development into the CAPRI farm-type model poses challenges with the top-down approach. It requires maintaining consistency with the regional NUTS2 level and considering farm-type-specific balances, indicators, and changes in the number of farms from the structural change estimation. The last section addressed methods for back-estimating censored data. I explored different data aggregation approaches, such as a local weighted average method and a Bayesian estimation procedure, to establish parameters for the censored data that match reality as closely as possible.