• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 15
  • 6
  • 2
  • 1
  • 1
  • Tagged with
  • 26
  • 26
  • 12
  • 9
  • 8
  • 6
  • 5
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Soil Practitioners and Vital Spaces| Agricultural Ethics and Life Processes in the Colombian Amazon

Lyons, Kristina Marie 23 November 2013 (has links)
<p> This dissertation is an ethnography of human-soil relations that examines the cultural, scientific, political-economic, and ethical stakes of alternative agricultural practices and life processes that resist military-led, growth-oriented development. Moving across laboratories, greenhouses, forests and farms, it weaves together a symmetrical analysis of two kinds of local-practitioners&mdash;soil scientists in the capital city of Bogot&aacute; and small farmers in the southwestern frontier department of Putumayo&mdash;to track how soils emerge with political importance in the construction of what I call agro-life proposals for peace in the Colombian Amazon. Theoretically, it interrogates concepts of "sustainability" emerging among scientists and farmers, suggesting they imply a complex reframing of liberal notions of property, health, wellbeing, labor and autonomy. These observations reimagine the interface between political economy and ecology and science and technology studies that can account for new ecological notions of territoriality linked to practices of economic 'degrowth', and the alternative agricultural life-worlds I encountered in southwestern Colombia.</p>
2

Cultivating Sustainability| Impact of Campus Agriculture Projects on Undergraduate Student Connections to Nature, Environmentally Responsible Behaviors, and Perceptions

LaCharite, Kerri 17 February 2015 (has links)
<p> The number of colleges and universities with campus agriculture projects in the US has grown from an estimated 23 in 1992 to 300 today with possibly increased numbers predicted. The profile emerging from campus agriculture projects looks a lot different from the traditional land grant colleges of agriculture. In spite of this emergent trend and staunch advocacy for campus agriculture projects, limited empirical research on agriculture-based learning in higher education exists outside agriculture degrees and theoretical work of scholars such as Liberty Hyde Bailey and David Orr. The purpose of this exploratory research was two-fold. First, prevailing characteristics and pedagogical objectives of campus agriculture projects were explored through a survey of all known US campus agriculture project managers and educators. Second, interviews, photo-elicitation, field observations, and use of the Connectedness to Nature Scale and Inclusion of Nature Scale were conducted during the summer of 2013 at Yale Farm and the University of Montana's Program in Ecological Agriculture and Society Farm (P.E.A.S.). At these two farms, I studied whether and in what ways did academic courses connected to campus agriculture projects at US colleges impact participating students' perceptions of and connection to nature. </p><p> This mixed methods research illustrates a re-visioning of how higher education is interfacing with agriculture and agriculture-based education beyond traditional land grant colleges of agriculture through attention to sustainability initiatives and pedagogies. Agriculture-based education and campus agriculture projects can distinctively impact students' perceptions of connectedness to nature through experiencing agriculture's role in establishing a new worldview. Data offers empirical evidence that campus agriculture projects deepen connection to place, and offers substitutes to anthropocentric beliefs and behaviors. While experiences at the campus agriculture projects motivated pro-environmental and social behaviors specific to farming, food, and the more-than-human community at the farms, participating students did not report an increase in cognitive connectedness to nature or behaviors beyond food, farming, or the more-than-human community at the farms.</p>
3

Small and Midscale Dairy Farming in the Northeast| Achieving Economic Resilience through Business Opportunity Analysis

Fisher, Taryn E. 24 January 2014 (has links)
<p> This dissertation investigates the dairy farming industry in the Northeastern United States and, in particular, the key drivers of economic viability and competitive advantage for small and midscale commercial dairy producers. The research approach employed was a literature review combined with primary case study observation and data collection. Historical perspective has been presented to provide an overarching contextual framework for this study. Four dairy farms were purposefully selected for case study research because they represented various aspects of a pre-defined set of variables and because they demonstrated relevant similarities as well as significant differences in terms of alternative business strategy. The classical business opportunity analytical process has been customized for practical use application by small and midscale dairy farmers. This tailored process has been validated using research findings; it offers a fresh way of identifying a strategic approach in pursuit of economic viability and competitive advantage that best fits an operation's unique set of characteristics. This process is intended for practical use application on a broader scale by dairy farmers in the Northeast to facilitate their understanding of challenging industry dynamics, of emergent market opportunity and inherent potency, and of both internal and external hurdles to be overcome. Finally, recommendations for next steps have been presented.</p>
4

Aspectos da produtividade do feijoeiro correlacionados com atributos do solo sob sistemas de manejo de elevado nível tecnológico

Montanari, Rafael [UNESP] 25 June 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:35:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-06-25Bitstream added on 2014-06-13T20:26:27Z : No. of bitstreams: 1 montanari_r_dr_ilha.pdf: 3462214 bytes, checksum: 126a0e7445267ab921363de7da210fe3 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / No Brasil, a cultura do feijoeiro constitui-se numa das mais representativas explorações agrícolas, não só sua pela área de cultivo como também pelo valor econômico de sua produção. No ano agrícola de 2006/07, no município de Selvíria (MS), foi analisada a produtividade de grãos do feijoeiro, em função de alguns atributos de um Latossolo Vermelho distroférrico, cultivado nas condições de elevado nível tecnológico de manejo, representados pelo sistema cultivo mínimo e pelo sistema plantio direto, e irrigado com pivô central. Os objetivos foram: a) analisar, nos dois sistemas de manejo empregados, a diferença de produtividade de grãos do feijoeiro, embasada nas diferenças existentes entre os valores médios dos atributos do solo trabalhado, e b) definir o atributo do solo para os dois sistemas de preparo, que melhor se apresente para explicar a variabilidade da produtividade de grãos do feijoeiro. Para tanto, foram instaladas duas malhas geoestatísticas, uma para cada sistema de manejo, para a coleta de dados do solo e da planta, com 117 pontos amostrais cada, numa área de 2025 m2 e declive homogêneo de 0,055 m m-1. Os resultados mostraram que, em relação ao sistema cultivo mínimo do solo, no sistema plantio direto ocorreu um aumento da heterogeneidade dos atributos da planta. Já em relação aos do solo, ocorreu aumento da homogeneidade. Também, a menor produtividade de grãos do feijoeiro, ocorrida no sistema cultivo mínimo do solo, foi provavelmente devido a uma menor densidade de plantas que esse sistema proporcionou. Ainda que no sistema plantio direto o solo cultivado estivesse mais compactado, evidenciado, sobretudo, pelos maiores valores da densidade do solo, resistência à penetração e umidade volumétrica, nele ocorreu maior e significativa produtividade de grãos do feijoeiro. Dessa forma... / In Brazil, the common bean crop is one of the most representative agriculture explorations, not just for its cultivation area, as well as for its production value. The common bean crop productivity was analyzed in function of some attributes of a Dystroferric Red Latosol (Typic Acrustox) in the agriculture year 2006/07, in Selviria County, Mato Grosso do Sul State, Brazil. It was cultivated with high technological level of management conditions by minimal tillage and no-tillage systems, irrigated by central pivot. The objectives were: a) to analyze both systems in order to obtain the difference of the common bean grains productivity, based on the existent differences among the medium values of the cultivated soil attributes, and b) to define on both systems the soil attribute that better showed the variability of the grains productivity. Two geostatistical grids were installed - one for each management system - to have the soil and plant data collected, with 117 sampling points each, in an area of 2025 m² and homogeneous slope of 0.055m m-1. Therefore, in relation to the minimal tillage system, on the no-tillage system, an increasing on the heterogeneity of the plant attributes occurred. By the other hand, there was a homogeneity increasing of the soil attributes. A minor common bean grains productivity also occurred. Due to the minor plant density provided by this system, the soil minimum tillage system, a minor bean grains productivity also occurred. Even if in the no-tillage area where the soil was more compacted, fact showed by the higher values of the bulk density and by the index cone as well as by the volumetric moisture, a major and expressive bean grains productivity occurred. So, for both soil tillage crop and no-tillage systems, such productivity could be explained through high significative mathematic models, respectively showed... (Complete abstract click electronic access below)
5

Modelagem de dados de cana-de-açúcar: uma abordagem multivariada / Modeling in of sugar cane data: a multivariate approach

Araújo, Elton Gean [UNESP] 29 November 2016 (has links)
Submitted by ELTON GEAN ARAUJO null (egarauj@yahoo.com.br) on 2016-12-09T14:27:08Z No. of bitstreams: 1 Tese_Doutorado_Elton.pdf: 2121651 bytes, checksum: cff49db4ef9e211e8525780187ba4329 (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-12-13T11:01:03Z (GMT) No. of bitstreams: 1 araujo_eg_dr_ilha.pdf: 2121651 bytes, checksum: cff49db4ef9e211e8525780187ba4329 (MD5) / Made available in DSpace on 2016-12-13T11:01:03Z (GMT). No. of bitstreams: 1 araujo_eg_dr_ilha.pdf: 2121651 bytes, checksum: cff49db4ef9e211e8525780187ba4329 (MD5) Previous issue date: 2016-11-29 / Neste trabalho, foram estudadas as interações entre os componentes de produção e tecnológicos da cana-de-açúcar, bem como da dinâmica de carbono no solo e os fatores latentes formados pelos atributos físicos e químicos do solo, por meio de modelos de análise de equações estruturais, com auxílio das técnicas estatísticas multivariadas análise dos componentes principais e análise fatorial. Ensaios experimentais foram conduzidos em diferentes localidades dos estados de São Paulo (Áreas com Argissolo Vermelho Distrófico abrúptico textura média/argilosa, Latossolo Vermelho Eutroférrico textura muito argilosa e Latossolo Vermelho Eutroférrico textura argilosa) e Mato Grosso do Sul (Área com Latossolo Vermelho-Amarelo distrófico textura franco argilo arenosa). Na camada de 0 a 0,20 m do solo, os componentes de produção e tecnológicos da cana-de-açúcar foram influenciados de forma negativa e significativa apenas pelo fator latente atributos físicos (densidade do solo, porosidade total e macroporos do solo) na ordem de 2,6 (em módulo) mais do que o fator latente atributos químicos associados a acidez do solo (pHCa, pHK e pHag), evidenciando compactação causada pelo tráfego de máquinas (cana crua em 3º corte). No entanto, na camada de 0,20 a 0,40 m, apenas o fator latente atributos químicos influenciou de maneira positiva e significativa os componentes de produção e tecnológicos da cultura, na ordem de aproximadamente 3 vezes mais que os atributos físicos, evidenciando o efeito benéfico da aplicação de gesso após o primeiro corte. Em relação à dinâmica de carbono, expressa neste trabalho pelas variações da emissão de CO2 do solo e do estoque de carbono no solo (calculado para a camada de 0-0,10 m), estas foram principalmente influenciadas pelo fator latente atributos físicos (porosidade livre de água, densidade do solo e macroporos), na ordem de pelo menos 4 vezes (em módulo) mais do que o fator latente atributos químicos (teor de cálcio, teor de magnésio e capacidade de troca de cátions do solo), para as áreas de estudos localizadas no estado de São Paulo (municípios de Pradópolis e Guariba). Na área de Aparecida do Taboado-MS, constatou-se que as variações de emissão de CO2 não sofreram influência significativa dos fatores latentes atributos químicos e físicos; porém, as variações dos valores de estoque carbono, foram explicadas de forma estatisticamente significativas por esses dois fatores, sendo os coeficientes estruturais em relação aos fatores latentes atributos físicos e atributos químicos, iguais a -0,34 e 0,28, respectivamente. / In this work, were studied the interactions between production components and of technology of sugarcane as well as the carbon dynamics in soil and latent factors formed by the physical and chemical properties of the soil, through of structural equations analysis models, with the help of the statistical multivariate principal components analysis and factor analysis. Experimental trials were conducted at different locations in the states of São Paulo (Areas with Dystrophic Red Argisol, with medium-clay texture , Eutroferric Red Latosol very clayey texture and Eutroferric Red Latosol with clay texture) and Mato Grosso do Sul (Area with Dystrophic Red-Yellow Latosol, with sandy clay franc texture). In the layer 0 to 0.20 m above the ground, the components of production and technology of sugarcane were influenced negatively and significantly only by the latent factor physical attributes (bulk density, porosity and macropores), in the order of 2.6 (in module), more than latent factor attributes chemical associated with soil acidity (PHCA, PHK and pHag), showing compaction caused by machinery traffic (crude cane in 3rd cut). However, at the layer 0.20 to 0.40 m, only the latent factor chemical attributes it influenced significantly and positively the production components and technological of the culture, on the order of about 3 times more than the physical attributes, highlighting the beneficial effect of plaster application after the first cut. Regarding the carbon dynamics expressed in this work by the variations of soil CO2 emission and the stock of carbon in the soil (calculated for the layer of 0-0.10 m), these were mainly influenced by the latent factor physical attributes (porosity water-free, bulk density and macropores) in the order of at least 4 times (in module) more than the latent factor chemical attributes (calcium, magnesium content and exchange capacity of soil cations), for areas of localized studies in São Paulo (municipalities of Pradópolis and Guariba). In area Aparecida of Taboado-MS, it was found that variations in CO2 emission suffered no significant influence of the latent factors chemical and physical attributes; however, variations in carbon stock values were explained in statistically significant way by these two factors, being the structural coefficients in relation to the latent factors physical attributes and attributes chemical, equal to -0.34 and 0.28, respectively.
6

Proposta Metodológica de Análise Quantitativa da Sustentabilidade de Estabelecimentos Agropecuários Fluminenses / Methodological proposal for quantitative analysis of agricultural establishments sustainability

Márcia Monteiro Matos 26 September 2012 (has links)
O presente trabalho consistiu em realizar uma proposta metodológica de análise quantitativa da sustentabilidade de estabelecimentos agropecuários fluminenses através do emprego do marco metodológico proposto por Sauvenier et al. (2006) e van Cauwenbergh et al. (2007), denominado SAFE (Sustainability Assessment of Farming and the Environment Framework). Conforme a aplicação para sistemas agrários realizada por Sánchez-Fernández (2009) e por sua vez, incorporando a quarta dimensão da sustentabilidade (dimensão institucional), ademais das três dimensões clássicas neste tipo de análise (econômica, social e ambiental), seguindo a sugestão do IBGE (2010), com base nas recomendações do Livro Azul da ONU (1996). Esse procedimento contou com a colaboração e validação de um painel composto por 16 especialistas em agricultura fluminense o que permitiu selecionar 20 indicadores de sustentabilidade, derivados de 17 critérios, 8 princípios e 4 dimensões. Dos resultados alcançados e de seus possíveis desdobramentos, a proposta metodológica sugerida pode ser considerada uma ferramenta potencialmente útil para guiar as políticas públicas que incidem sobre o setor. / The aim of this study was to develop a practical methodology for evaluating the sustainability of farms by means of the methodological framework proposed by Sauvenier et al. (2006) and van Cauwenbergh et al. (2007), called SAFE (Sustainability Assessment of Farming and the Environment Framework), according to the application for agricultural systems performed by Sánchez-Fernández (2009) and incorporating the fourth dimension of sustainability (institutional dimension) besides the three classical dimensions adopted in this type of analysis (economic, social and environmental), following the suggestions of IBGE (2010), based on the recommendations of the UN Blue Book (1996). This procedure was validated by a panel of 16 experts in fluminense agriculture that supported the selection of 20 sustainability indicators, derived from 17 criteria, 8 principles and 4 dimensions. Through the results achieved and their possible outcomes, the proposed methodology for agricultural sustainability quantitative analysis could be considered as a potentially useful tool to improve current agricultural policies.
7

Proposta Metodológica de Análise Quantitativa da Sustentabilidade de Estabelecimentos Agropecuários Fluminenses / Methodological proposal for quantitative analysis of agricultural establishments sustainability

Márcia Monteiro Matos 26 September 2012 (has links)
O presente trabalho consistiu em realizar uma proposta metodológica de análise quantitativa da sustentabilidade de estabelecimentos agropecuários fluminenses através do emprego do marco metodológico proposto por Sauvenier et al. (2006) e van Cauwenbergh et al. (2007), denominado SAFE (Sustainability Assessment of Farming and the Environment Framework). Conforme a aplicação para sistemas agrários realizada por Sánchez-Fernández (2009) e por sua vez, incorporando a quarta dimensão da sustentabilidade (dimensão institucional), ademais das três dimensões clássicas neste tipo de análise (econômica, social e ambiental), seguindo a sugestão do IBGE (2010), com base nas recomendações do Livro Azul da ONU (1996). Esse procedimento contou com a colaboração e validação de um painel composto por 16 especialistas em agricultura fluminense o que permitiu selecionar 20 indicadores de sustentabilidade, derivados de 17 critérios, 8 princípios e 4 dimensões. Dos resultados alcançados e de seus possíveis desdobramentos, a proposta metodológica sugerida pode ser considerada uma ferramenta potencialmente útil para guiar as políticas públicas que incidem sobre o setor. / The aim of this study was to develop a practical methodology for evaluating the sustainability of farms by means of the methodological framework proposed by Sauvenier et al. (2006) and van Cauwenbergh et al. (2007), called SAFE (Sustainability Assessment of Farming and the Environment Framework), according to the application for agricultural systems performed by Sánchez-Fernández (2009) and incorporating the fourth dimension of sustainability (institutional dimension) besides the three classical dimensions adopted in this type of analysis (economic, social and environmental), following the suggestions of IBGE (2010), based on the recommendations of the UN Blue Book (1996). This procedure was validated by a panel of 16 experts in fluminense agriculture that supported the selection of 20 sustainability indicators, derived from 17 criteria, 8 principles and 4 dimensions. Through the results achieved and their possible outcomes, the proposed methodology for agricultural sustainability quantitative analysis could be considered as a potentially useful tool to improve current agricultural policies.
8

O impacto do PRONAF SustentÃvel sobre a sustentabilidade agrÃcola da agricultura familiar: o caso da microrregiÃo do Vale do MÃdio Curu no Estado do Cearà / The impact of PRONAF sustainable in agricultural sustainability on the family agriculture: the case of the Curu Valley Middle Microregion in CearÃ

Ana Tereza Bittencourt Passos 10 January 2014 (has links)
A agricultura ao longo dos anos tem tido um papel fundamental nos paÃses em desenvolvimento. NÃo obstante as inÃmeras funÃÃes que a atividade oferece na oferta de alimentos, fibras, biocombustÃvel as crÃticas mais frequentes dizem respeito a ameaÃa à sustentabilidade dos recursos naturais, terra e Ãgua. No entanto, a gestÃo sustentÃvel desses recursos tem sido a resposta a todas essas questÃes. O crÃdito rural assume lugar de destaque, por ser este o instrumento que permite dotar os agricultores familiares de capital produtivo, para desenvolver o negÃcio agrÃcola. O Programa Nacional de Fortalecimento da Agricultura Familiar â PRONAF SustentÃvel à a Ãnica polÃtica destinada a esse pÃblico e, prestes a completar sua maioridade, ainda nÃo tem convencido os estudiosos de sua real contribuiÃÃo. O presente estudo tem por objetivos mensurar os Ãndices de sustentabilidade agrÃcola de agricultores familiares, mediante a construÃÃo do Ãndice de GestÃo da Propriedade; estimar os impactos do PRONAF SustentÃvel sobre a sustentabilidade agrÃcola e a receita agrÃcola anual destes agricultores atravÃs do modelo Propensity Score Matching. Os dados utilizados sÃo de origem primÃria, obtidos atravÃs da aplicaÃÃo de 60 questionÃrios semiestruturados, para beneficiÃrios e 125 para nÃo beneficiÃrios do Programa, totalizando 185 questionÃrios nos municÃpios de SÃo LuÃs do Curu e Pentecoste, situados na microrregiÃo do Vale do MÃdio Curu no estado do CearÃ. Os resultados demonstram que o Ãndice de GestÃo da Propriedade (IGP) dos beneficiÃrios do Programa, representativo da sustentabilidade agrÃcola em suas trÃs dimensÃes: ambiental, econÃmica e social Ã, inequivocamente, superior ao IGP dos nÃo beneficiÃrios. As variÃveis que mais influenciaram a inclusÃo de nÃo beneficiÃrios no Programa sÃo: escolaridade, Ãgua disponÃvel na propriedade, condiÃÃes de moradia, Ãrea colhida, tempo de trabalho na propriedade e nÃmero de cÃmodos. O PRONAF SustentÃvel apresenta efeitos positivos para o Ãndice de GestÃo EconÃmica, para o Ãndice de GestÃo Social, para o Ãndice de GestÃo da Propriedade e para a Receita AgrÃcola Anual de seus beneficiÃrios. Dada a relevÃncia e a abrangÃncia do PRONAF SustentÃvel, sugere-se a realizaÃÃo de estudos mais aprofundados para o estado do Cearà e para a regiÃo Nordeste. Ademais, de forma a complementar os resultados gerais da avaliaÃÃo, recomenda-se estender os estudos para as demais linhas e modalidade de crÃdito que compÃe o Programa. / The agriculture over the years has been instrumental in developing countries. Nevertheless, the numerous functions that the activity offers in offering food, fiber, biofuel the most frequent criticisms concern the threat to the sustainability of natural resources, land and water. However, the sustainable management of these resources has been the answer to all these questions. Rural credit takes pride of place, as this is the instrument that allows to equip farmers in productive capital, to develop agricultural business. The National Program for Strengthening Family Agriculture â PRONAF Sustainable is the only policy to this public, and about to complete his majority, still has not convinced scholars of his real contribution. The present study aims to measure the indices agricultural sustainability of family farmers through the construction the index of Property Management; estimating impacts of Sustainable PRONAF over agricultural sustainability and annual agricultural revenue of these farmers through the model Propensity Score Matching. The data used are of primary origin, obtained by the application of 60 semi-structured questionnaires to 125 beneficiaries and non-beneficiaries of the Program, a total of 185 questionnaires in the municipalities of SÃo LuÃs do Curu and Pentecoste, situated in the micro region Valley Middle Curu state CearÃ. The results demonstrate that the Property Management Index (IGP) of the beneficiaries of the Program representative of agricultural sustainability in its three dimensions: environmental, economic and social is unequivocally superior to the IGP not beneficiaries. The variables that most influenced the inclusion of non-beneficiaries in the Program are: schooling, water available on the property, housing conditions, harvested area, working time on the property and number of rooms. The Sustainable PRONAF shows positive effects on the Index of Economic Management for the Social Management Index, for Index Management of Property and to the Annual Agricultural Revenue beneficiaries. Given the relevance and comprehensiveness of Sustainable PRONAF, it is suggested to conduct further studies to the state of Cearà and the Northeast. Moreover, in order to complement the overall results of the evaluation, it is recommended extending the studies to other credit modalities and lines that make up the Program.
9

EVALUATING THE EFFECTS OF ORGANIC AND CONVENTIONAL INPUTS ON SOIL CHEMICAL AND BIOLOGICAL PROPERTIES IN A FOUR-YEAR VEGETABLE ROTATION AND THE INVESTIGATION OF SOIL MICROBIAL PROPERTIES ON PLANT GENE EXPRESSION

Law, Audrey 01 January 2009 (has links)
The objective of this research was to determine the effects of conventional inputs on soil chemical and biological properties compared to organic systems in a four year vegetable rotation. Tillage and cover crops were the same in all treatments to avoid confounding factors often present in similar research. Additional experiments investigated plant gene expression in organic and conventional management systems and in soils with decreased microbial diversity. Experimental plots were prepared in the spring of 2004; four replications of three management treatments, organic, low-input and conventional, were arranged in a randomized complete block design. The rotation consisted of edamame soybean, sweet corn, fallow (pastured poultry in organic plots), and potatoes. Soil samples were taken in the spring and fall of each year, along with data for pest damage, weed control, yield and quality. Soil samples were analyzed for enzyme activity (maximum activity under substrate saturation) and basic soil chemical properties. Treatments were compared over time using 2-Way ANOVA. Multiplex terminal-restriction fragment length polymorphism (M-TRFLP) profiles of the soil microbial community were compared using Multiple Response Permutation Procedures (MRPP). Multi-way ANOVA detected significant treatment effects over time in total carbon, nitrogen, Mehlich III K, Exchangeable K and exchangeable Na (p=0.05). Many significant changes in soil properties over time could not be attributed to treatment effects. All treatments produced similar yields, indicating that successful organic production of these vegetables is possible in Kentucky. Input costs for organic were 37% higher than conventional, due to the cost of organic fertilizer. The organic system required nearly 50% more labor hours than conventional or low-input. The low-input system was the most cost effective, with 58% less input expenses than the conventional system. Microarray analysis of approximately 37,500 Glycine max transcripts did not show significant differences in the gene expression between plants grown organically and conventionally, in plots with significant soil chemical and microbial differences. An experiment in progress is investigating changes in plant gene expression using real time RT-PCR in tomatoes grown in autoclaved soil and native field soil.
10

Aspectos da produtividade do feijoeiro correlacionados com atributos do solo sob sistemas de manejo de elevado nível tecnológico /

Montanari, Rafael. January 2009 (has links)
Orientador: Morel de Passos e Carvalho / Banca: Orivaldo Arf / Banca: Marcelo Andreotti / Banca: Gener Tadeu Pereira / Banca: Ednaldo Carvalho Guimarães / Resumo: No Brasil, a cultura do feijoeiro constitui-se numa das mais representativas explorações agrícolas, não só sua pela área de cultivo como também pelo valor econômico de sua produção. No ano agrícola de 2006/07, no município de Selvíria (MS), foi analisada a produtividade de grãos do feijoeiro, em função de alguns atributos de um Latossolo Vermelho distroférrico, cultivado nas condições de elevado nível tecnológico de manejo, representados pelo sistema cultivo mínimo e pelo sistema plantio direto, e irrigado com pivô central. Os objetivos foram: a) analisar, nos dois sistemas de manejo empregados, a diferença de produtividade de grãos do feijoeiro, embasada nas diferenças existentes entre os valores médios dos atributos do solo trabalhado, e b) definir o atributo do solo para os dois sistemas de preparo, que melhor se apresente para explicar a variabilidade da produtividade de grãos do feijoeiro. Para tanto, foram instaladas duas malhas geoestatísticas, uma para cada sistema de manejo, para a coleta de dados do solo e da planta, com 117 pontos amostrais cada, numa área de 2025 m2 e declive homogêneo de 0,055 m m-1. Os resultados mostraram que, em relação ao sistema cultivo mínimo do solo, no sistema plantio direto ocorreu um aumento da heterogeneidade dos atributos da planta. Já em relação aos do solo, ocorreu aumento da homogeneidade. Também, a menor produtividade de grãos do feijoeiro, ocorrida no sistema cultivo mínimo do solo, foi provavelmente devido a uma menor densidade de plantas que esse sistema proporcionou. Ainda que no sistema plantio direto o solo cultivado estivesse mais compactado, evidenciado, sobretudo, pelos maiores valores da densidade do solo, resistência à penetração e umidade volumétrica, nele ocorreu maior e significativa produtividade de grãos do feijoeiro. Dessa forma... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In Brazil, the common bean crop is one of the most representative agriculture explorations, not just for its cultivation area, as well as for its production value. The common bean crop productivity was analyzed in function of some attributes of a Dystroferric Red Latosol (Typic Acrustox) in the agriculture year 2006/07, in Selviria County, Mato Grosso do Sul State, Brazil. It was cultivated with high technological level of management conditions by minimal tillage and no-tillage systems, irrigated by central pivot. The objectives were: a) to analyze both systems in order to obtain the difference of the common bean grains productivity, based on the existent differences among the medium values of the cultivated soil attributes, and b) to define on both systems the soil attribute that better showed the variability of the grains productivity. Two geostatistical grids were installed - one for each management system - to have the soil and plant data collected, with 117 sampling points each, in an area of 2025 m² and homogeneous slope of 0.055m m-1. Therefore, in relation to the minimal tillage system, on the no-tillage system, an increasing on the heterogeneity of the plant attributes occurred. By the other hand, there was a homogeneity increasing of the soil attributes. A minor common bean grains productivity also occurred. Due to the minor plant density provided by this system, the soil minimum tillage system, a minor bean grains productivity also occurred. Even if in the no-tillage area where the soil was more compacted, fact showed by the higher values of the bulk density and by the index cone as well as by the volumetric moisture, a major and expressive bean grains productivity occurred. So, for both soil tillage crop and no-tillage systems, such productivity could be explained through high significative mathematic models, respectively showed... (Complete abstract click electronic access below) / Doutor

Page generated in 0.122 seconds