Orientador: Ademar Ribeiro Romeiro / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Economia / Made available in DSpace on 2018-08-15T17:59:26Z (GMT). No. of bitstreams: 1 Mangabeira_JoaoAlfredodeCarvalho_D.pdf: 11845686 bytes, checksum: d32784bf5e1dfac41e1ecee49bc6f383 (MD5) Previous issue date: 2010 / Resumo: O objetivo deste trabalho é o de traçar a tipologia dos produtores rurais do município de Machadinho d'Oeste - RO, oriundos de um projeto de assentamento do Incra, quanto ao seu nível de acumulação de capital, durante o período de 1986 a 2008, no sentido de definir os fatores que levaram aos diferentes níveis de capitalização desses produtores, bem como avaliar o papel dos serviços ambientais nesta trajetória. A metodologia baseia-se no geoprocessamento, na Análise de Correspondência Múltipla (ACM) e na distribuição espacial dos agricultores familiares em função de seu nível de capitalização e da distância das propriedades em relação às reservas em bloco criadas em Machadinho d'Oeste. O uso de imagens de satélite de alta resolução espacial permitiu aferir os dados de uso das terras no campo. A ACM foi utilizada para estabelecer todas as possíveis correlações entre os produtores amostrados e as variáveis selecionadas, seguida da análise de conglomerados, pelo método de Ward, para classificá-los em tipos distintos. Os resultados mostram a existência de 5 tipos de produtores: produtores capitalizados (Tipo 1), razoavelmente capitalizados (Tipo 2), medianamente capitalizados (Tipo3), pouco capitalizados (Tipo 4), e descapitalizados (Tipo 5). A geoestatística foi usada para analisar a distribuição espacial, quanto ao nível de capitalização, em relação à distância das reservas. Complementarmente foi analisada a produtividade do café, principal cultura de geração de renda na região, e sua relação com a distância das propriedades às reservas. Os resultados mostram que as propriedades com café plantado próximo às matas, em média, apresentam maior produtividade e melhor desempenho. Observou-se também que, em maior quantidade, propriedades com melhor nível de capitalização situam-se próximas às reservas, evidenciando a existência de serviços ambientais prestados pelas matas. A metodologia mostrou-se adequada e consistente aos estudos propostos para este trabalho e representa, portanto, um interessante caminho metodológico para estudos futuros sobre levantamento dos recursos naturais, valoração de serviços ambientais, avaliação e análises de impactos ambientais, sociais e econômicos da agricultura, estudos de sustentabilidade agrícola e pesquisas espaço-temporais do uso das terras / Abstract: The objective of this thesis is to outline the typology of the smallholders in Machadinho d'Oeste, state of Rondônia, regarding their level of capital accumulation, from 1986 to 2008, in order to determine the factors that led them to different levels of capitalization as well to assess the role of the environmental services in this process. The methodology is based on geoprocessing, on Multiple Correspondence Analysis (MCA) and on the spatial distribution of the smallholders according to both their level of capitalization and the distance of their proprieties from the communal forest reserves present in Machadinho d'Oeste. High spatial resolution satellite images made it possible to check the data about land use in the field. The MCA was used to establish all the possible correlations between the sampling of smallholders and the selected variables, followed by Ward's cluster analysis, so as to classify the smallholders in distinct types. The results indicate that there are five types of smallholders: capitalized (type 1), quite capitalized (type 2), moderately capitalized (type 3), poorly capitalized (type 4) and under-capitalized (type 5). Geostatistics was used to analyze spatial distribution, taking into account the level of capitalization in relation to the distance of the properties from the reserves. In addition, the relationship between the productivity of coffee and the distance of these profitable crops from the reserves was analyzed. The results show that the coffee that grows near the forests has higher productivity and a better performance. It is also possible to state that the best capitalized properties are located near the reserves, highlighting the role played by the environmental services provided by the forests. The methodology proved to be consistent with the cases studied in this research thus representing an effective approach to further studies on natural resources, environmental services valuation, analysis and assessment of environmental, social and economical impact on agriculture, agricultural sustainability analysis and temporal and spatial research on land use / Doutorado / Desenvolvimento Economico, Espaço e Meio Ambiente / Doutor em Desenvolvimento Economico

In rain-fed farming systems, a poor harvest can have broad and overwhelming effects on affected households. Smallholder farmers have to ensure that they have adequate food from one harvest to the other and enough inputs for the next farming season. Households consume more just after the harvest and the consumption levels decline as they move away from the harvest season. The study identified the ex-ante and ex-post adjustment mechanisms to seasonal food and input requirements. Special consideration was given to determine whether the probability of using a given adjustment mechanism to seasonality is the same in good, normal, poor and very poor years and whether household wealth has an influence on the use of adjustment mechanisms. Attention was also given to determining whether agricultural production and household wealth are reflected in observed seasonality in consumption. The study used cross-sectional data from 225 randomly selected households. The study relied on non-parametric methods of data analysis because the required dependent variables could not meet the parametric assumptions. The analysis showed that the probabilities of using some ex-ante and ex-post adjustment mechanisms for both food and input requirements by the non-poor households are not the same in good, normal, poor and very poor years. However, the poor households’ probability of using any of the identified ex-post adjustment mechanisms to seasonal input requirements is the same in all the years. The study established that household wealth affects the use of ex-ante and ex-post adjustment mechanisms to seasonal input requirements and ex-post adjustment mechanisms to seasonal food requirements after good, normal, poor and very poor harvests. The study further revealed that agricultural production is reflected in household seasonal consumption. However, the study failed to find a relationship between consumption and agricultural production in the post-harvest season after good and normal harvests. The study also showed that household wealth is reflected in food consumption in all the seasons of normal, poor and very poor years. However, no relationship was found between food consumption and household wealth in the post-harvest and rainy seasons after good harvests. The study further revealed that there is always a seasonal fall in consumption levels among households of all wealth strata despite the use of adjustment mechanisms. The situation worsens as we move from the good years towards the very poor years. The study suggests that the use of one size fits all type of interventions to minimise the seasonality problem cannot adequately achieve the required results for all households. It is important to know the way households from each wealth stratum respond to the seasonality problem and why they respond in such a way. Programmes that encourage strategic planning, agricultural production and wealth creation are necessary to reduce the seasonality problem. Furthermore, mechanisms which ensure that the benefits from government interventions reach the poor households are necessary. / Dissertation (MSc Agric)--University of Pretoria, 2013. / gm2014 / Agricultural Economics, Extension and Rural Development / unrestricted

Thesis (MPhil)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The aim of this study was to provide the first in depth description of the natuurboerdery farming system as developed and adopted by ZZ2, a privately-owned farming conglomerate in South Africa. Natuurboerdery aims to increase agricultural productivity and sustainability while maintaining environmental integrity to contribute to overall sustainability. A case study research design using multiple sources and techniques for data gathering was applied to investigate the reasons for and process of converting from conventional farming to natuurboerdery, describe the principles and practices of natuurboerdery farming and document the changes and benefits realised by conversion. It was established that ZZ2 converted to natuurboerdery farming due to the challenges associated with conventional methods of farming. The main challenges ZZ2 experienced were recurrent pests and diseases which were becoming difficult to control with inorganic pesticides, large decreases in yields and unsustainable production outputs or returns to support production costs mainly due to the escalating cost of inorganic pesticides and fertilisers. ZZ2 also became aware of the growing customer demand for healthy food produced by ethically accepted methods while minimising environmental degradation. A conceptual framework was developed to describe the natuurboerdery farming system, based on five principles or health aspects: agro-ecosystem health, soil health, plant health, food health and human health. All of the practices developed and adopted by ZZ2 were described and classified in terms of this framework. Natuurboerdery integrates the use of inorganic fertilisers and organic soil amendments for soil health and plant nutrition; inorganic pesticides, fermented plant extracts from herbal plants with insecticidal properties, EM products, compost teas and biological control agents for plant protection. The conversion to natuurboerdery resulted in changes and benefits which were described and classified under: strategic and technical, economic, social and ecological and environmental. The main findings were that soil health has improved, soil organic carbon levels have increased, the use of inorganic products for plant nutrition and protection has decreased with significant cost savings, yields have risen, water availability has increased and energy spending has been reduced. The conclusions drawn from the research findings indicate that natuurboerdery is neither organic nor conventional farming which indicates that inorganic and organic inputs are compatible in sustainable farming systems. The natuurboerdery farming approach is a potentially sustainable farming system which works with nature. Areas for further scholarship, research and recommendations have been identified to improve the sustainability of natuurboerdery. / AFRIKAANSE OPSOMMING: Die doel van hierdie tesis was om die eerste in-diepte beskrywing van natuurboerdery saam te stel soos dit deur ZZ2 ontwikkel en gebruik is. ZZ2 is ‘n Suid Afrikaanse boerdery konglomoraat in privaatbesit. Natuurboerdery beoog om boerdery produktiwiteit en volhoubaarheid te verhoog, terwyl dit die integriteit van die natuuur in stand hou om tot algehele volhoubaarheid by te dra. ‘n Gevallestudie is as navosingsontwerp gebruik en verskeie bronne en metodes is toegepas om inligting in te samel. Die proses en redes vir die oorskakeling van konvensionele boerdery na natuurboerdery is ondersoek, terwyl die beginsels en praktyke van natuurboerdery beskryf is en die veranderings en voordele van die oorskakeling gedokumenteer is. Dit is vasgestel dat ZZ2 na natuurboerdery omgeskakel het as gevolg van uitdagings wat met konvensionele boerderymetodes gesassosieer word. Die hoof-uitdagings wat ZZ2 ondervind het was terugkerende peste en siektes wat moeilik beheerbaar was met onorganiese plaagdoders, groot afnames van oeste en onvolhoubare produksie uitkomste of winste om die produksiekostes te dra. Stygende pryse van onorganiese plaagdoders en kunsmis was die grootste oorsaak van hoë produksiekostes. ZZ2 het ook bewus geraak van die groeinde klante-aanvraag vir gesonde kos wat op eties-aanvaarbare metodes geproduseer is en skade aan die natuurlike omgewing verminder. ‘n Konsepsuele raamwerk is ontwikkel om natuurboerdery as ‘n boerdery-sisteem te beskryf en is gebasseer om vyf beginsels of gesondheidsaspekte: agroekosisteemgesondheid, grondgesondheid, plantgesondheid, voedselgesondheid en menslike gesondheid. Al hierdie praktyke wat deur ZZ2 ontwikkel en gebruik is word in hierdie tesis beskryf en geklassifisseer in terme van die konsepsuele raamwerk. Natuurbeordery integreer die gebruik van onorganiese kunsmis en organiese grondwysigings vir grondgesondheid en plantvoeding. Geïntegreerde praktyke sluit in: onorganieise plaagdoders, gefermenteerde kruieplant-ekstrakte met insek-bestrydende einskappe, EM produkte, kompos-tees en biologiese beheeragente vir plantbeskerming. Die oorskakeling na natuurboerdery het sekere veranderings en voordele gehad. Dit word geklassifiseer volgens die betrekking wat dit het op die strategiese en tegniese, ekonomiese, maatskaplike en ekologiese en omgewings-aspekte van ZZ2. Die hoofbevindings was verbeterde grondgesondheid, verhoogde organiese koolstofvlakke in die grond, laer gebruik van onorganiese produkte vir plantvoeding en beskerming met noemenswaardige koste-besparings, verhoodge oeste en waterbeskikbaarheid, en kleiner spandering op energie. Die navorsingsbevindings wys daarop dat natuurboerdery nie organies of konvensionele boerdery is nie en dat onorganiese en organiese insette dus verenigbaar is in volhoubare boerdery-sisteme. Die natuurboerdery uitkyk is ‘n potensiële volhoubare boerderysisteem wat in staat is om saam die natuur te werk. Areas vir verdere studie, navorsing en voorstelle is geïdentifiseer om die volhoubaarheid van natuurboerdery te verbeter.

Les travaux présentés dans cette thèse portent sur la notion de performance environnementale comme cadre analytique pour l’étude des impacts des activités agricoles sur l’environnement. Après avoir mis en évidence un manque de formalisation de cette notion dans la littérature, nous la définissons comme la distance entre l’état environnemental d’un écosystème à un moment donné et un état environnemental à atteindre pour cet écosystème, dit « de haute performance environnementale ». Dans cette étude, l’état environnemental est approché par trois critères liés à la ressource « eau » : les concentrations en nitrates et en matières en suspension, et les débits.Suite à la description de l’état initial, nous proposons une méthode d’optimisation de la performance environnementale des activités agricoles basée sur un couplage entre un modèle agro-hydrologique (SWAT) et un modèle d’optimisation multicritère (Weighted Goal Programming). La démarche d’optimisation considère la réaffectation spatialisée de systèmes de culture sur l’espace considéré comme facteur d’amélioration, les différents critères de l’optimisation étant examinés simultanément.La méthode est implémentée sur le bassin versant de la Boulouze (coteaux de Gascogne). Les résultats montrent une amélioration de la performance environnementale du système étudié. L’analyse de la nouvelle occupation des sols souligne qu’au-delà des évolutions quantitatives des surfaces allouées aux systèmes de culture, la spatialisation des changements d’un système vers un autre influe également sur la performance environnementale à l’échelle du bassin versant. Enfin, nous interrogeons l’applicabilité de cette méthode et mettons en évidence l’intérêt qu’elle présente comme outil à la fois de modélisation de scénarios et de communication. / We introduce in this thesis the notion of environmental performance as an analytical framework aimed at studying the impacts of agricultural activities on the environment. We outline first a need to formalize this notion and then define it as the distance between the “environmental” state of a system at a specific time and a state of “high environmental performance” to achieve. Focus is on water management at the watershed level with three criteria: nitrogen, sediments (water quality) and water flows (water quantity).Our aim is to optimize the environmental performance of agricultural activities at the watershed scale. First the initial status of the watershed is described, then a method is proposed. This method is based on a coupling between an agro-hydrological model, the Soil and Water Assessment Tool (SWAT), and the Weighted Goal Programming optimization method. Our purpose is the reallocation of farming systems within the watershed when considering the optimization criteria simultaneously.We implement this method on the Boulouze watershed (coteaux de Gascogne, in the southwestern part of France). Results outline an improvement of the environmental performance. The analysis of the new land-use plan emphasizes the fact that the changes of farming systems are not only due to evolutions of the surfaces where they are implemented, but that the environmental performance at watershed scale is also affected by their location.Finally we explore the applicability of the method used highlighting its attributes as a relevant tool for modeling scenarios and for communicating.

<div>The goal of this research was to improve crop yield and quality and enhance nutrient use efficiency of aquaponics for the development of sustainable aquaponic production system. Aquaponics is the integration of aquaculture and hydroponics by recirculating water and residual nutrients resulting from aquaculture wastewater into hydroponic crop production. The project had four objectives. The first objective was to characterize nutrient composition and accumulation in recirculating water and plant parts of tomato, basil, and lettuce grown in aquaponic systems, and to compare their growth and yield with those grown in hydroponic systems. The second objective was to determine the effects of feeding management regime on water quality, crop yield and quality, and N use efficiency for vegetable and herb production in recirculating aquaponics in comparison to hydroponics. The third objective was to optimize water-flow rate for efficient aquaponic system for maximum crop yield. The fourth objective was to investigate and compare the N and P mass balance between aquaponics and hydroponics. Four conclusions were determined that 1) Aquaponic solution was deficient in Ca and/or Mg leading to plant nutrient deficiency but sufficient or high in P; And luxuriant nutrient profiles in hydroponics are not necessary to enhance crop yield in aquaponics as long as key factors affecting crop yield are identified and properly addressed. 2) Uniform feeding regime improved water quality by reducing toxic ions and enhancing initial nutrient availability and considerably increased the yield, quality and nitrogen use efficiency (NUE) of crops in aquaponics as close or similar to those in hydroponics. 3) Flow rate is an important factor affecting water quality parameters and optimizing flow rate is essential to maximize aquaponic crop production and improve energy efficiency; High hydraulic loading rate at 3.3 m3/m2-day improved performance and yield of all crops in an aquaponics system regardless of their growth rate, but the water hydraulic loading rate for fast-growing and medium-growing crops can be reduced to 2.2 m3/m2-day without production reduction. 4) Plant species had significant influence on N and P removal and mass balance in aquaponics and hydroponics; Fruity vegetables showed better growth adaption in aquaponic system, while yields of leafy vegetables may be reduced when grown in aquaponics than hydroponics; Aquaponics is more efficient than hydroponics releasing less environmental wastes, however, N and P use efficiency in aquaponics and hydroponics can be further improved via proper management.</div><div>The important findings obtained from this research will fill the knowledge gap in aquaponic research and provide new management strategies to improve quantitative study of aquaponic crop production and new management strategies for cultivating crops in aquaponics. The findings will also greatly contribute to the commercial aquaponic development, and ultimately improve food security and resource use efficiency in the US and global agricultural production.</div>

Os sistemas de cultivo agrícola são essenciais à sociedade. A questão atual é saber como mantê-los produtivos sem afetar drasticamente os diferentes ecossistemas e ciclos biogeoquímicos. Sabe-se que a atividade biológica dos solos é de crucial importância à saúde dos mesmos e à produtividade. Deste modo, a implantação de técnicas ambientalmente corretas com monitoramentos eficientes, baseados na qualidade do solo, é fundamental para valorizar a sua conservação. Esta tem sido o foco de pesquisas nas últimas décadas, sendo que refletem ação antrópica, principalmente pela emissão dos gases do efeito estufa (GEEs). O uso de sistemas conservacionistas destaca-se pela viabilidade econômica e ambientalmente benéfica em relação ao manejo convencional. O sistema integração lavoura-pecuária tem sido utilizado para minimizar os impactos ambientais da exploração agrícola, a fim de preservar as características físicas, químicas e biológicas do solo, estendendo sua resiliência e aumentando a produtividade. Os microrganismos são responsáveis por diversos processos biológicos essenciais ao ambiente e algumas espécies participam produzindo ou oxidando o metano (CH4), um dos gases do efeito estufa. Estes são influenciados principalmente pelas mudanças de uso do solo, que quando relacionadas ao manejo inadequado podem alterar a qualidade do solo, a produtividade e a emissão de gases. Assim, a avaliação dos solos dos sistemas agrícolas, sob a interação rizosférica de diferentes culturas e a criação de um ambiente anóxico se faz necessário para entender o comportamento de tais comunidades. Os sistemas de integração lavoura-pecuária e a rotação de culturas foram investigados em relação a microbiota funcional do solo, em função de fatores como ao histórico da área e umidade. Foram avaliadas a abundância, por PCR em tempo real, e a estrutura das comunidades Archaea e Bacteria por TRFLP, e a potencialidade de atuação do solo como emissor e mitigador de CH4 através da quantificação dos microrganismos metanogênicos e metanotróficos de áreas agrícolas e reflorestamento do Alto Xingu, no município de Querência. Com elas foi possível observar que os microrganismos são estruturados, primariamente, em função do tipo de solo e consecutivo efeito rizosférico dos vegetais, de forma que os sistemas de integração lavoura-pecuária (ILP) apresentaram sutilmente maior estabilidade em relação ao sistema rotacionado de soja/milheto, devido ao sistema radicular da pastagem fornecer maior proteção e liberação de exsudatos. Pelas semelhanças existentes com os sistemas ILP, a área de reflorestamento se encontra em recuperação transitória, em uma média da similaridade entre as enzimas de restrição HhaI e MspI, de 85%; e 65% em relação à floresta, que se estruturou de maneira diferenciada das demais áreas. Outro fator de diferenciação das áreas agrícolas foi a forte influência da calagem o que eleva o pH e concomitantemente apresentou teores elevados de Ca e Mg. Já as comunidades de metanotróficas não apresentaram variação em função das metanogênicas, em que a saturação hídrica promoveu seu crescimento somente nos solos de floresta, onde ocorre maior incorporação de matéria orgânica / Agricultural faming systems are essential to society. The current question is how to keep them productive without drastically affecting different ecosystems and biogeochemical cycles. It is known that the soil biological activity is crucial to the health and productivity. Thus, the implementation of environmentally correct techniques with efficient monitoring, based on soil quality is critical to enhance their conservation. This has been the focus of research in recent decades, and reflects human action, mainly by the emission of greenhouse gases (GHGs). The use of conservation tillage systems distinguished by economic viability and environmentally beneficial compared to conventional tillage systems. The crop-livestock system has been used to minimize the environmental impacts of farming, in order to preserve the physical, chemical and biological soil properties, extending its resilience and increasing productivity. Microorganisms are responsible for many essential biological processes to the environment and some species participate in production or oxidation of methane (CH4), a greenhouse gas. These are mainly influenced by land use changes, that when related to inadequate management may alter soil quality, productivity and gases emissions. Thus, the evaluation of soils for agricultural systems under the rhizospheric interaction of different cultures and creating an anoxic environment is needed to understand the behavior of such communities. Crop-livestock systems and crop rotation were investigated in relation to functional soil microbiota, depending on factors such as the area history and moisture. Genes abundance were assessed by real-time PCR, while Archaea and Bacteria community structure by TRFLP, and the potential role of soil as releaser and mitigator of CH4 through the quantification of methanogens and methanotrophs in agricultural areas and reforestation of the Upper Xingu, at Querência city. Through the techniques of qPCR and TRFLP was observed that microorganisms are structured primarily on the type of soil, followed by rhizosphere effect of plants. In this way, crop-livestock integration systems (CLI) are subtly stable then rotational system of soybean/millet due to pasture root system to provide greater protection and root exudation. Alike CLI systems, the reforestation area is in transient recovery on average between the restriction enzymes HhaI and MspI, 85%; and 65% in relation to forest, this structures itself in a differentiated manner from the other areas. The farming areas present strong influence of liming, which leads to grow pH and concomitantly high Ca and Mg contents. The methanotrophic community did not vary due to the methanogenic community, and the water saturation promotes the growth of methanogenic communities only in forest soils where occurs greater organic matter incorporation

As práticas agrícolas, muito além de processos estritamente ecológicos, constituem processos sociais. Simplificações na dinâmica ecológica, impostas pela artificialização dos sistemas agrícolas, tem causado desequilíbrios entre produção e diversidade de espécies. A utilização de modernas tecnologias de manejo agrícola, desenvolvidas com o intuito de restabelecer o funcionamento de agrossistemas complexos e facilitar mecanismos de autoregulação do ambiente, estão amplamente conectadas a questões socioeconômicas. Concebidas com o propósito de conservar e ampliar a biodiversidade, facilitar a ciclagem de nutrientes, assim como diminuir impactos ao solo (tais como erodibilidade e compactação) além de, entre outros efeitos, preservar a umidade dos solos e propiciar microclima mais estável e ameno, as tecnologias de integração agropecuária e florestal tem sido implementadas em diferentes regiões do mundo. Pesquisas tem sido conduzidas quanto às práticas de implementação adequadas a cada ecossistema e às especificidades locais, com a expectativa de obtenção de resultados satisfatórios a partir das perspectivas ecológica, agronômica, econômica e social. Identificar e avaliar o grau de identificação dos pequenos e médios produtores rurais do município de Ipameri, sudeste de Goiás, com formas de produção agrícola diversificadas e integradas, bem como a viabilidade de utilização destas tecnologias em seu cotidiano, são os propósitos desta pesquisa. Buscou-se compreender, a partir da perspectiva destes atores sociais, as implicações dos efeitos decorrentes de variáveis econômicas, sociais, ambientais e simbólicas inerentes às práticas agronômicas eleitas por estes produtores, para condução de suas atividades e expressão de seus valores, preceitos, tradições e estilos de organização social. Concluiu-se que os sistemas integrados constituem alternativas para recuperação de áreas de pastagens degradas e da paisagem, representam oportunidades de geração de empregos, diversificação de renda para micro, pequenos e médios produtores locais. A despeito das dificuldades elencadas pelos interagentes da pesquisa para sua implementação, constitui-se em uma estratégia compreendida como viável e de interesse para os potenciais usuários / Agricultural practices, beyond strictly ecological processes, are social processes. Simplifications in the ecological dynamics imposed by the artificiality of agricultural systems, has caused imbalances between production and species diversity. The use of modern farm management technologies developed in order to restore the functioning of complex agrosystems and facilitate environmental autoregulation mechanisms are widely connected to socio-economic issues. Designed in order to build and expand biodiversity, facilitate nutrient cycling, as well as to reduce impacts to the soil (such as erodibility and compression) besides other effects, to preserve the moisture of the soil and provide more stable and mild microclimate, the agricultural and forestry integration technologies have been implemented in different regions of the world. Researches have been conducted on appropriate implementation practices for every ecosystem and to local conditions, with the expectation of obtaining satisfactory results from the ecological, agronomic, economic and social perspectives. Identify and assess the degree of identification of small and medium farmers in the municipality of Ipameri, southeast of Goiás, with forms of diversified and integrated farming as well as the feasibility of using these technologies in their daily lives, are the purposes of this research. We seek to understand, from the perspective of these social actors, the implications of the effects of economic, social, environmental and symbolic variables inherent to agronomic practices elected by these producers to conduct their activities and to express their values, principles, traditions and styles of social organization. It was concluded that integrated systems constitute alternatives for recovery of degraded areas of pastures and landscape, representing opportunities for job creation, diversification of incomes for micro, small and medium local producers. Despite the difficulties listed by interactors, its implementation is a strategy understood as feasible and of interest to potential users

A história da agricultura da metade norte do estado do Rio Grande do Sul revela que essa grande região foi alvo de um intenso processo de colonização ao final do século XIX e início do século XX, de modo que atualmente a região é predominante marcada pela presença numerosa de estabelecimentos da agricultura familiar. No entanto, nota-se que processo de colonização regional apresenta heterogeneidades, sendo que são identificados locais periféricos, no noroeste gaúcho, que se caracterizam por terem sofrido um processo de ocupação tardio. O objetivo desse trabalho repousa em analisar a formação, a evolução e as perspectivas de desenvolvimento da agricultura em regiões periféricas do Rio Grande do Sul, utilizando como unidade de análise os municípios de Porto Lucena e Porto e Porto Vera Cruz. Para tanto o trabalho se baseou teórica e metodologicamente sobre a Teoria dos Sistemas Agrários. Como resultado, a história da agricultura local pode ser retratada pela a sucessão de quatro Sistemas Agrários. Constatou-se que o processo de ocupação da região possuiu especificidades que tanto se distinguem dos processos ocorridos em outras regiões do noroeste, como também foram capazes de conferir diferenças e contrastantes entre os agricultores destes municípios, identificadas ainda nos dias atuais. A análise da agricultura contemporânea revelou a existência de sete Tipos de agricultores que incidem sobre a dinâmica atual. Tais tipos possuem, características e estratégias de reprodução social diferentes, imprimindo também dinâmicas diferenciadas e plurais sobre as perspectivas do desenvolvimento agrícola e rural local. / The agricultural history in the northern of Rio Grande do Sul State shows that this large region was target of an intense colonization process between the end of the 19th century and beginning of the 20th century, as a result the region nowadays is characterized by a large presence of family farming establishments. Nevertheless, the regional colonization process has showed significant heterogeneities in this region and therefore it can be identified peripheral sites, in the northwest for instance, due to the late occupation process. The aim of this study was to analyze agriculture formation, evolution and perspectives of development in the peripheral regions of Rio Grande do Sul State, using as an analyze unity the municipalities of Porto Lucena and Porto Vera Cruz. Therefore, this study is theoretically and methodologically based on the Agrarian Systems theory. Consequently, the local agriculture history is characterized by a succession of four agrarian systems. The study has verified singularities in the occupation process of this region, they were different from the others occurred in the northwest region of this state, and it also occurred differences and contrasts between farmers from these towns, phenomena yet present nowadays. The analysis of contemporary agriculture revealed the existence of seven types of farmers that affect the current dynamics. These farmer types have different characteristics and strategies of social reproductions, also expressing different and plural dynamics about agriculture and rural development perspectives.

<p>Arbuscular mycorrhizal fungi (AMF) are best known for their potential to help plants acquire nutrients, especially phosphorous. These microbes improve soil health by promoting soil aggregation and carbon sequestration, and further benefit plants by helping them withstand biotic and abiotic stress. Currently, there are 200 recognized species of AMF within the phylum Glomeromycota. Recent studies indicate that individual AMF species differ in the benefits they provide, with some even acting as parasites. Moreover, AMF community composition can be altered by soil and crop management practices, but the effect of these changes on the benefits conferred by AMF are still not well understood. Consequently, the goal of this study was to determine how two widely used crop management systems can alter the composition of AMF species, and affect the potential for these communities to promote the productivity and drought tolerance. To accomplish this goal, we collected AMF inoculum from a long-term crop systems trial comparing organic and conventional management for use in greenhouse trials where we subjected plants to drought. We collected AMF inoculum during mid-summer when differences between the two management systems were likely cause larger effects on AMF communities, and again in autumn after harvest to see if differences in AMF communities would persist. We determined AMF species composition using next generation sequencing. Results of this study confirm that soil-building practices commonly used in organic farming systems can improve soil health and increase the productivity of food-grade soybeans. They also demonstrate that AMF communities in Indiana croplands are highly diverse, and some of these taxa can improve soybean growth and help plants tolerate water stress. Although the overall diversity of AMF communities did not differ between the organic and conventional management systems in mid-summer, individual AMF taxa did differ between the systems, which were likely responsible for the greater tolerance to water stress observed when plants were amended with inoculum from the organic system. AMF communities present during autumn were significantly different between the two crop management systems, but did not result in differences in drought tolerance of soybeans, indicating that the loss of key AMF taxa in the organic system from the first relative to the second experiment was likely responsible. Finally, plants grown using inoculum from both crop management systems in autumn had greater tolerance to water stress than plants that received a AMF commercial inoculum. This provides further evidence that individual AMF species vary in the benefits they provide, and that the presence of a diverse consortium of AMF species is needed to optimize plant health and productivity in agricultural systems. Agricultural producers should consider incorporating soil-building practices that are commonly used in organic farming systems such as planting winter cover crops, to improve the health of their soil and enhance the productivity of their crops. <b></b></p> <br>

The complex co-evolutionary systems approach -CCeSA - provides a well-suited framework for analysing agricultural systems, serving as a bridge between physical and socioeconomic sciences, alowing for the explaination of phenomena, and for the use of metaphors for thinking and action. By studying agricultural systems as self-generated, hierarchical, complex co-evolutionary farming systems - CCeFSs -, one can investigate the interconnections between the elements that constitute CCeFSs, along with the relationships between CCeFSs and other sytems, as a fundamental step to understanding sustainability as an emergent property of the system. CCeFSs are defined as human activity systems emerging from the purposes, gestalt, mental models, history and weltanschauung of the farm manager, and from his dynamic co-evolution with the environment while managing the resources at his hand to achieve his own multiple, conflicting, dynamic, semi-structured, and often incommensurable and conflicting purposes while performing above thresholds for failure, and enough flexibility to dynamically co-evolve with its changing biophysical and socioeconomic environment for a given future period. Fitness and flexibility are essential features of sustainable CCeFSs because they describe the systems' dynamic capacity to explore and exploit their dynamic phase space while co-evolving with it. This implies that a sustainable CCeFS is conceived as a set of dynamic, co-evolutionary processes, contrasting with the standard view of sustainability as an equilibrium or steady-state. Achieving sustainable CCeFSs is a semi-structured, constrained, multi-objective and dynamic optimisation management problem, with an intractable search space, that can be solved within CCeSA with the help of a multi-objective co-evolutionary optimisation tool. Carnico-ICSPEA2, a co-evolutionary navigator - CoEvoNav -used as a CCeSA's tool for harnessing the complexity of the CCeFS of interest and its environment towards sustainability, is introduced. The software was designed by its end-user - the farm manager and author of this thesis - as an aid for the analysis and optimisation of the San Francisco ranch, a beef cattle enterprise running on temperate pastures and fodder crops in the Central Plateau of Mexico. By combining a non-linear simulator and a multi-objective evolutionary algorithm with a deterministic and stochastic framework, the CoEvoNav imitates the co-evolutionary pattern of the CCeFS of interest. As such, the software was used by the farm manager to navigate through his CCeFS's co-evolutionary phase space towards achieving sustainability at farm level. The ultimate goal was to enhance the farm manager's decision-making process and co-evolutionary skills, through an increased understanding of his system, the co-evolutionary process between his mental models, the CCeFS, and the CoEvoNav, and the continuous discovery of new, improved sets of heuristics. An overview of the methodological, theoretical and philosophical framework of the thesis is introduced. Also, a survey of the Mexican economy, its agricultural sector, and a statistical review of the Mexican beef industry is presented. Concepts such as modern agriculture, the reductionist approach to agricultural research, models, the system's environment, sustainability, conventional and sustainable agriculture, complexity, evolution, simulators, and multi-objective optimisation tools are extensively reviewed. Issues concerning the impossibility of predicting the long-term future behaviour of CCeFSs, along with the use of simulators as decision support tools in the quest for sustainable CCeFSs are discussed. The rationale behind the simulator used for this study, along with that of the multi-objective evolutionary tools used as a makeup of Carnico-ICSPEA2 are explained. A description of the San Francisco ranch, its key on-farm sustainability indicators in the form of objective functions, constraints, and decision variables, and the semi-structured, multi-objective, dynamic, constrained management problem posed by the farm manager's planned introduction of a herd of bulls for fattening as a way to increase the fitness of his CCeFS via a better management of the system's feed surpluses and the acquisition of a new pick-up truck are described as a case study. The tested scenario and the experimental design for the simulations are presented as well. Results from using the CoEvoNav as the farm manager's extended phenotype to solve his multi-objective optimisation problem are described, along with the implications for the management and sustainability of the CCeFS. Finally, the approach and tools developed are evaluated, and the progress made in relation to methodological, theoretical, philosophical and conceptual notions is reviewed along with some future topics for research.