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  • 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.
701

Feasibility of Green Building at WPI

Peyser, Suzanne M 30 April 2008 (has links)
College campuses, with significant numbers of older facilities, have the opportunity to lead the green building movement while reaping economic, health, environmental, educational, and marketing benefits. This project assessed the current status of green building programs at Worcester Polytechnic Institute (WPI), the costs and benefits of building green, and the costs and benefits of LEED certification to make the business case for LEED-certified buildings. This project also proposed a strategic plan for green building programs at WPI to promote and measure green building improvements to new and existing facilities. Lastly, this project assessed the feasibility of certifying existing facilities with the LEED Existing Building rating system. By evaluating all of the costs and the major benefits, the results of this project demonstrate that the benefits of building green and LEED certification outweigh the costs and that through strategic planning WPI can become a leader among colleges implementing green building programs.
702

Proposição de um modelo conceitual para avaliação da maturidade em Green IT em organizações

Viaro, Thiago Arena 11 March 2011 (has links)
Submitted by Mariana Dornelles Vargas (marianadv) on 2015-05-20T15:03:48Z No. of bitstreams: 1 proposicao_modelo.pdf: 5422246 bytes, checksum: a961877e46ec533ea17e0c5126f50b4d (MD5) / Made available in DSpace on 2015-05-20T15:03:48Z (GMT). No. of bitstreams: 1 proposicao_modelo.pdf: 5422246 bytes, checksum: a961877e46ec533ea17e0c5126f50b4d (MD5) Previous issue date: 2011 / Nenhuma / A demanda da sociedade por respostas imediatas às questões ambientais tem pressionado as organizações a tomarem medidas para tornarem seus negócios verdes, isto é, com mínimo impacto ambiental. Neste contexto, Green IT (Tecnologia da Informação Verde) surge como uma alternativa a tornar os processos vinculados à Tecnologia da Informação, de maneira geral, mais sustentáveis ambientalmente. Esta pesquisa propõe um método e um modelo conceitual para avaliação da maturidade em Green IT nas organizações. A proposta é embasada em um levantamento bibliográfico, envolvendo temas correlatos como Responsabilidade Social Corporativa, Gestão Verde, Sustentabilidade Ambiental e Green IT, propriamente dita, tendo sido avaliada por meio de um painel com especialistas nas temáticas abordadas. O modelo conceitual proposto é constituído de quatro dimensões identificadas a partir da revisão da literatura: economia, tecnologia, meio ambiente e processo, e possui uma escala de maturidade em Green IT formulada a partir de alguns modelos de referência estudados. A partir deste modelo, construiu-se o método de avaliação em Green IT que visa identificar o nível de maturidade da organização. Ele se divide em três etapas: (i) contextualização, (ii) aplicação e (iii) análise e discussão. Este método envolve observações diretas, entrevistas e análise de documentos, além de um formulário de análise - baseado na escala de maturidade proposta - e um gráfico ilustrativo da maturidade da organização, cunhado neste estudo como Green IT Diamond. Ambos, método e modelo propostos, foram aplicados no SAP Labs Latin America - subsidiária da empresa de software SAP, com o objetivo de evidenciar empiricamente as proposições. Os resultados oriundos desta aplicação foram discutidos à luz do modelo teórico proposto e do referencial teórico consultado, o que possibilitou avaliar a maturidade em Green IT e identificar pontos de melhoria na organização. / Society claims for immediate responses to the environmental concerns have pushed organizations to adopt measures for greening their business, i.e., with minimum environmental impact. In this context, Green IT emerged as an alternative to make the processes related to Information Technology more sustainable. This research proposes a conceptual model and a method to evaluate Green IT maturity of organizations. This proposal is based on literature review involving related topics like Corporate Social Responsibility, Green Management, Environmental Sustainability, and Green IT, itself, and it was evaluated by a panel of experts in the tackled subjects. The conceptual model consists of four dimensions identified from the literature review: economy, technology, environment and process, and has a maturity scale proposed in Green IT from some reference models studied. From this model, it was constructed a method of Green IT evaluation which aims to identify the maturity level of the organization. It is divided into three stages: (i) context, (ii) implementation and (iii) analysis and discussion. This method involves direct observations, interviews and documents' analisys, and an Analysis Form - based on the maturity scale proposed - and a graph illustrating the maturity of the organization, coined in the study of Green IT Diamond. Both, the proposed method and model, were applied in SAP Labs Latin America - a subsidiary of the software company SAP - with the purpose of analysing the propositions empirically. The results from this application were discussed in light of the theoretical model and theoretical framework consulted, which allowed to evaluate Green IT maturity and identify areas for improvement within the organization.
703

Cálculo da condutividade térmica do Argônio sólido puro e com defeito pontual

Trindade, Ranyere Deyler 14 March 2008 (has links)
Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2014-07-31T12:16:56Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Calculo_da_condutividade_termica_do_argonio_solido_puro_e_com_defeito_pontual.pdf: 283748 bytes, checksum: d7815053104cf5341740be05c829feff (MD5) / Made available in DSpace on 2014-07-31T12:16:57Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Calculo_da_condutividade_termica_do_argonio_solido_puro_e_com_defeito_pontual.pdf: 283748 bytes, checksum: d7815053104cf5341740be05c829feff (MD5) Previous issue date: 2008-03-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this work, using the Green-Kubo method combined with Molecular Dynamic (DM), we calculate the thermal conductivity of a solid Argon "free of defects"and with point defect present, for temperatures varying from 10 up to 60 K at density 22,3 ml/mol. The obtained results are in good agreement with the available theoretical and experimental results in the limites of low and high temperatures, but with some discrepances in about 15 % for intermediate values of temperatures. The purpose to include point defects with the objective of correction of the simulational results to compare with experimental measuremments for intermediate temperatues had not the expected e?ect. However, we believe that it should be due to the fact that the density used in the simulation for the point defect is high based on the experimental estimates of point defect density in this system. Our results suggest that the Green-Kubo method combined with Molecular Dynamics is a powerful tool to calculate the thermal conductivity of solids at high temperatures. With the construction of accurate and reliable interatomic potentials to describe more complex materials, such as high temperature ceramic and minerals at extreme condiction of pressure and temperature, this method could soon become very useful to calculate thermal conductivity in materials where the access to experimental data is hard. / Neste trabalho, usando o método de Green-Kubo combinado com a Dinâmica Molecular (DM), calculamos a condutividade têrmica do Argônio sólido livre de defeitos ;e com defeitos pontuais presentes, para um intervalo de temperatura variando de 10 a 60 K e uma densidade de 22,3 ml/mol. Os resultados obtidos estão em pleno acordo com os resultados teóricos e experimentais disponíveis nos limites de baixa e alta temperatura, mas com alguma discrepância em torno de 15 % para valores intermediários de temperatura. A proposta para incluir defeitos pontuais com o objetivo de correção dos resultados da simulação para comparar com as medidas experimentais para temperaturas intermediárias não surtiu o efeito esperado, no entanto, acreditamos que isto se deve ao fato da densidade de defeitos ser alta baseado em estimativas da densidade de defeitos neste sistema. Nossos resultados sugerem que o método de Green-Kubo combinado com DM é uma ferramenta poderosa para se calcular a condutividade térmica de sólidos a altas temperaturas. Com a construção de potenciais interatômicos mais precisos e con fiáveis para descrever materiais mais complexos, como é o caso de cerâmicas a altas temperaturas e minerais em condições extrema de pressão e temperatura, esse método poderá em breve ser muito útil para calcular a condutividade térmica em materiais onde o acesso a dados experimentais é mais difícil.
704

Percepção dos executivos do valor das práticas verdes para o negócio

Prandes, Gilberto Roberto January 2014 (has links)
As práticas verdes vêm constantemente sendo discutidas devido a sua importância para as empresas e para a sociedade. Porém, ainda não se chegou a um consenso sobre todos os seus benefícios, quer sejam ambientais ou econômicos. Cada vez mais os estudos demonstram a capacidade de geração de valor das práticas verdes para as empresas e para a sociedade. Portanto, imagina-se que as mesmas irão influenciar a sua aplicação em segmentos que hoje não têm uma utilização mais efetiva de práticas ambientalmente corretas. O objetivo dessa pesquisa é medir o valor das práticas verdes na percepção dos executivos de organizações manufatureiras e de serviços. O método escolhido foi a pesquisa survey, realizada a partir de um instrumento previamente proposto, contendo 5 variáveis e 25 itens. A pesquisa survey foi realizada em duas etapas: estudo de pré-teste e estudo final. Diferentes técnicas estatísticas foram empregadas para refinar o instrumento, como Análise de Confiabilidade, Análise Fatorial Exploratória e Análise Fatorial Confirmatória. Como resultado desse refinamento emergiu um modelo teórico de pesquisa final contendo 5 variáveis, sendo as dimensões de Estratégia, Custos, Crescimento, Marca e Riscos em 25 itens, onde foi verificado que a variável Marca não se confirmou, pois não teve validade estatística no modelo testado. Também como contribuição para as empresas e sociedade, o modelo teórico de pesquisa final se mostrou adequado para avaliar o valor das práticas verdes para organizações. A principal contribuição da pesquisa para a prática gerencial é o mapeamento da percepção dos executivos a respeito dos benefícios que as práticas verdes proporcionam às suas organizações e um novo modelo representando o valor das práticas verdes. / Green practices are constantly being discussed due to their importance for business and society. However, a consensus on all its benefits has not been reached yet, whether on environmental or economic field. Increasingly, studies have demonstrated the ability to generate value of green practices for companies and society . Therefore, it is thought that they will influence their application in segments that currently have a more effective use of environmentally friendly practices. The objective of this research is to measure the value of green practices in the perception of executives of manufacturing and service organizations. The method chosen was the survey research conducted from a previously proposed instrument, containing 5 variables and 25 items. The survey was conducted in two stages: a pre-test study and a final study. Different statistical techniques were employed to refine the instrument, as Reliability Analysis, Exploratory Factor Analysis and Confirmatory Factor Analysis. As a result of this refinement a theoretical model for the final survey containing 5 variables has emerged, with the dimensions of Strategy, Cost, Growth, Brand and Risks with 25 items , which found that the variable Brand was not confirmed, it had no statistical validity in the model tested. Also, as a contribution to business and society, the theoretical model for the final survey was adequate to assess the value of green practices for organizations. The main contribution of the research for management practice are mapping the perceptions of executives about the benefits of green practices to their organizations and provide a new model representing the value of green practices.
705

Construçőes com certificaçőes leed no Brasil: o caso do Eldorado Business Tower

Santos, Mariana Feres dos 14 March 2012 (has links)
Made available in DSpace on 2016-03-15T19:21:44Z (GMT). No. of bitstreams: 1 Mariana Feres dos Santos .pdf: 10236399 bytes, checksum: c8342a03d98aa6f0259bf187860cab0e (MD5) Previous issue date: 2012-03-14 / The job is to analyze the certification system LEED, one of the most used and recognized in Brazil, through a case study of the first building to receive the highest level of the LEED CS certification in Latin American. The certification has been used to prove that a building is sustainable and this job analyzes the building using an architectural point of view, verifying if the certification ensures that the building has a sustainable architecture. The job will begin with a brief history about how sustainable development joined the world speech, explaining some of the key concepts related do the topic. After that, some examples of sustainable architecture and its definition will be shown. For the analysis of LEED, two other certifications were chosen for a brief comparative scenario: BREEAM, the first certification to be used and which served as the basis for many others, and AQUA, another certification that has been used in Brazil. For the case study of Eldorado Business Tower, it will be done a brief history of the project and an analysis of the building through the project, the certification process and observations made in the visit to the site. / O trabalho consiste na análise da certificação LEED, uma das mais utilizadas e reconhecidas no Brasil, através de um estudo de caso do primeiro edifício a receber o mais alto nível da certificação LEED CS na América Latina. A certificação tem sido utilizada como meio de comprovação que um edifício é sustentável e esse trabalho analisa o edifício do ponto de vista arquitetônico, verificando se a certificação garante a este uma arquitetura sustentável. O desenvolvimento do trabalho começa com um breve histórico sobre como o desenvolvimento sustentável entrou para o discurso mundial, explicando alguns dos principais conceitos relacionados ao tema. Em seguida, são mostrados exemplos de arquitetura classificada como sustentável e a definição desta. Para a análise do LEED, é desenvolvido um breve cenário comparativo entre duas outras certificações: o BREEAM, a primeira certificação a ser utilizada e que serviu como base para muitas outras, e o AQUA, outra certificação que vem sendo utilizada no Brasil. Para o estudo de caso do Eldorado Business Tower, é feito um breve histórico do projeto e uma análise do edifício a partir do projeto, do processo de certificação e de observações realizadas em visita feita ao local.
706

Comportamento térmico de um sistema de cobertura verde: um experimento utilizando plataformas de teste / Thermal behavior of a green roof system: an experiment using test platforms

Perussi, Rafael 30 September 2016 (has links)
A utilização de coberturas verdes nas edificações traz vantagens como a regulação das temperaturas no ambiente construído, a melhora na eficiência energética, a retenção das águas pluviais, a atenuação dos efeitos das ilhas de calor e o aumento da biodiversidade no ambiente urbano. O objetivo desta pesquisa é analisar experimentalmente o comportamento térmico de um sistema extensivo de cobertura verde em comparação com uma cobertura controle sem vegetação no período de transição entre as estações primavera-verão. O experimento foi composto por duas plataformas de teste construídas de forma a reproduzir um sistema de cobertura verde extensivo, sendo que uma plataforma recebeu o plantio de grama-amendoim e a outra foi mantida sem cobertura vegetal. Foram monitoradas as temperaturas dos níveis superior e inferior do substrato e também as temperaturas externas, abaixo da base das plataformas, por meio de termopares instalados em locais pré-determinados conectados a um sistema de aquisição de dados. Os dados de radiação solar global e das principais variáveis climáticas foram registrados pela estação meteorológica automática do Centro de Recursos Hídricos e Estudos Ambientais (CRHEA) da Universidade de São Paulo (USP) em Itirapina- SP, local onde foi conduzido o estudo. As análises do comportamento térmico foram realizadas a partir das abordagens espacial e temporal da Climatologia Dinâmica como forma de conhecer a influência das flutuações do tempo meteorológico possibilitando a identificação de episódios climáticos e suas repercussões sobre os valores das temperaturas obtidas das plataformas de teste através da elaboração e análise de gráficos, com o auxílio das cartas sinóticas e imagens de satélite, para identificação do episódio representativo e escolha dos dias típicos experimentais. Os resultados indicaram que a cobertura verde apresentou melhor desempenho térmico em relação à cobertura controle por ter apresentado maior atraso térmico entre as superfícies superior e inferior, menor amplitude térmica nas superfícies e temperaturas máximas menores do que a temperatura máxima do ar. Concluiu-se que, para um dia quente e seco, a cobertura do substrato com uma camada densa de vegetação influencia os processos de troca de calor no perfil do substrato pelo bloqueio de parte da radiação solar incidente, fator principal que determina esses processos, permitindo que a superfície superior não atinja temperaturas acima da temperatura máxima do ar diária e também que esta temperatura se manifeste com maior atraso na superfície inferior. / The use of green roofs in buildings brings advantages such as the regulation of temperatures in the built environment, the improvement in energy efficiency, storm water retention, mitigating the heat islands effect and increasing biodiversity in the urban environment. The aim of this study is to analyze experimentally the thermal behavior of an extensive green roof system compared to a control roof with just soil layer in spring-summer transition period. The experiment consisted of two test platforms built to reproduce an extensive green roof system, one of wich was planted with perennial peanut and the other one was kept without vegetation. The temperatures of the upper and lower levels of the substrate and also external temperatures below the base of the platforms were monitored by means of thermocouples installed in predetermined locations connected to a data acquisition system. Global solar radiation data and the main climatic variables were recorded by the automatic weather station at the Centre for Water Resources and Environmental Studies (CRHEA), University of São Paulo (USP) in Itirapina-SP, where the study was conducted. The analysis of the thermal behavior was based on the spatial and temporal approaches of dynamic climatology to know the influence of weather fluctuations enabling the identification of climatic episodes and their impact on the temperature values obtained from the test platforms by means of charts and verified by synoptic maps and satellite imagery for the identification of the representative episode and choice of the typical experimental days. The results indicated that green roof showed better thermal performance compared to control coverage by having larger thermal lag between the upper and lower surfaces, the lower temperature range on surfaces and lower maximum temperatures than the maximum air temperature. It was concluded that for a hot, dry day, a layer of a dense vegetation cover influences the heat exchange process in the substrate layer by blocking a part of the solar radiation, the main factor that determines these processes, allowing the upper surface does not reach temperatures above the maximum daily air temperature and also that this temperature be registred with higher delay at the bottom surface.
707

[en] STUDY OF TRANSPORT OF POLYMER POLYANILINE / [pt] ESTUDO DE TRANSPORTE DE CARGA DE POLÍMEROS DE POLIANILINA

RONALD MARCOS ARCOS PADILLA 11 October 2011 (has links)
[pt] O desenvolvimento de materiais com propriedades elétricas incomuns, como é o caso dos polímeros condutores, vem sendo estudado por muito tempo. Este tipo de sistema orgânico apresenta característica isolante pura, mas quando são introduzidas impurezas por meio da dopagem variam a sua condutividade de forma significativa em comparação com os metais. No presente trabalho, investigamos o transporte de carga eletrônica no sistema molecular do polímero Polianilina (PAN), através de cálculos quânticos mediante o método de Hückel e acoplado com a metodologia das funções de Green de não equilíbrio (FGNE) foram obtidas expressões para a condutância e densidade local de estados (LDOS). Realiza-se o estudo da estrutura eletrônica da PAN conformada de 200 anéis apresentando algum tipo de defeito estrutural tipo polaron o bipolaron onde os efeitos provocados pela desordem desempenham um papel fundamental. Investigamos assim a LDOS e a condutância para formações de cadeias de PAN tanto protonadas e não protonadas, verificando assim que a rede bipolarônica presente na estrutura do sistema apresenta um deslocamento da energia de Fermi para dentro da banda de valência, região de estados espacialmente estendidos onde a condutância é finita, comprovando assim a transição metal-isolante para este material. / [en] The development of materials with unusual electrical properties as is the case of conducting polymers has been studied for a long time. This type of organic system provides insulation characteristic pure, but when impurities are introduced by doping the conductivity varies significantly in comparison with metals. In this study, we investigated the transport of electronic charge in the system polymer molecular Polyaniline (PAN) through quantum calculations by the Hückel method and coupled with the methodology of Green functions of nonequilibrium (FGNE) were obtained expressions for the conductance and local density of states (LDOS). Is carried out to study the electronic structure of PAN conformed to 200 rings showing some type of structural defect type polaron bipolaron where the effects of the disorder play a key role. Thus investigated the LDOS and conductance to PAN formation of chains of both protonated and non protonated, thus verifying that the structure of the bipolaron in this system has a displacement of the Fermi energy into the valence band region of spatially extended states where conductance is finite, thus proving the metal-insulator transition for this material.
708

O teorema de Green-Tao: progressões aritméticas de tamanho arbitrariamente grande formadas por primos / The Green-Tao theorem: arbitrarily long arithmetic progressions on primes

Cunha, Matheus Gonçalves Cassiano da 27 June 2019 (has links)
Encontrar subestruturas aditivas que revelam um certo grau de organização em certos conjuntos contidos nos números naturais é o foco do estudo da combinatória aditiva. Desta área, resultados como os famosos Teorema de Van der Waerden e o Teorema de Szemerédi se destacam, revelando através de métodos combinatoriais que certas propriedades referentes ao tamanho de subconjuntos de inteiros implicam a existência de progressões aritméticas de tamanho arbitrariamente grande. Em meados de 1970, Furstenberg causou certa comoção no meio matemático ao publicar provas para ambos os teoremas usando métodos e ferramentas da teoria ergódica. Apesar de tal abordagem ter apresentado uma nova e profunda ligação entre as áreas, houve certa crítica pelo fato de não gerar resultados originais e por suas limitações (por exemplo, seus resultados costumam ser de caráter assintótico, sem lidar com limitantes e cotas, amplamente conhecidos pelos métodos combinatórios). Tais críticas foram silenciadas quando Ben Green e Terence Tao, usando tais métodos de teoria ergódica, demonstraram a incrível e bela afirmação de que os primos possuem progressões aritméticas de tamanho arbitrariamente grande, dando uma resposta definitiva para um enunciado conjecturado há muito tempo. Certamente, este foi um grande passo na matemática do século XXI. Deste então, novas abordagens foram amplamente estudadas e analisadas, de modo a aumentar ainda mais nossa compreensão sobre estes impressionantes conceitos. / Finding additive substructures that reveal a certain degree of organization in certain sets contained in the set of the natural numbers is the focus of the study of additive combinatorics. From this area, results such as the famous Van der Waerdens Theorem and Szemerédis Theorem stand out, revealing through combinatorial methods that certain properties concerning the size of subsets of integers imply the existence of arbitrarily long arithmetic progressions. In the mid-1970s Furstenberg caused some commotion in the mathematical world by publishing proofs for both theorems using methods and tools of ergodic theory rather than combinatorial methods. Although this approach had presented a new and deep link between those areas, there was some criticism for the lack of original results and some limitations of this technique (for instance, its results usually have an asymptotic flavour without dealing with bounds widely known by combinatorial methods). Such criticisms were silenced when Ben Green and Terence Tao, using such methods of ergodic theory, demonstrated the incredible and beautiful theorem that the primes have arithmetic progressions of arbitrarily large size, giving a definitive answer to a statement conjectured a long time ago. Certainly, this was a major step for the mathematics of the 21st century. Hence, new approaches have been extensively studied and analyzed in order to further increase our understanding of these impressive concepts.
709

The Olympic Games –  An Instrument for Environmental Political Change. : A case study exploring the Environmental Political approaches of the Olympic Games – with special focus on the 28th Summer Olympic Games in Beijing.

Karlsson, Lukas January 2009 (has links)
<p><strong>UNIVERSITY OF KALMAR - SWEDEN</strong></p><p>The institution of Social Science</p><p>Project: Master Essay 15points</p><p>Title: Olympic Games – An instrument for Environmental Political Change?</p><p> </p><p><em>-A case study exploring the Environmental Political views of the Olympic Games – with special focus on the 28th Summer Olympic Games in Beijing. </em></p><p> <strong>ABSTRACT                                                               </strong></p><p>The essay´s aim was to explore the complex political environmental opinions and opportunities to use the Olympic Games as an instrument for environmental political changes, with special focus on the 2008 summer Olympics Games in Beijing. </p><p>In the light of two environmental political theories (The Green Business and Critical Ecology Theories)  The International Olympic Committee's (The IOC) third pillar, the environment, the Beijing Olympic Committee 's motto (BOCOG) “Green Olympics” and Non-Governmental Organisations (NGO:s) such as Greenpeace and their motto “Green Games” have been reviewed. The aim was to see the organisations aim to use the Beijing Olympics as a tool for environmental political changes.  </p><p>The study involves six qualitative interviews, one group interview, one written questionnaire and participating observations, during an eight week field study, during the Beijing Olympics in 2008.</p><p>The conclusion of the study demonstrates that the Olympic Games can be used as important instrument to address the organisations environmental work toward a “Greening” of Olympic cities with firstly technical measures under political control.  The Olympics are also used as an instrument to raise the environmental awareness of the public in Beijing and China.</p><p>The City of Beijing was seen as a showcase of green standards hopefully to be spread nationally. The “Greening of Olympics” is still though a complex social and scientific matter. Countries and cities have different conditions, knowledge, interests and ambitions. Universal standards are not always universally understood.</p><p> </p>
710

Role of green manure options in organic cropping systems

Marufu, Gift 22 June 2010
On the Canadian prairies, organic production generally includes the use of annual green manure (GrM) crops, which are terminated using tillage to add nutrients and organic matter to the soil. However, in a GrM plough-down year, farmers face loss of income. As an alternative to growing traditional GrM crops, legumes can be grown alone or intercropped with cereals and harvested as green feed forage (GF) for use on-farm or for sale to other producers without depleting soil nitrogen (N) for the subsequent crop. We hypothesized that the GF system would have similar biomass, and N yield, and ultimately would return N into the soil. Furthermore, by intercropping a legume with a cereal, biological N2-fixation will be enhanced in the legume.<p> Field experiments, conducted over two years, were established at Vonda and Delisle, Saskatchewan, Canada. The experiment was conducted using a randomized complete block design (RCBD) with 16 treatments and four replicates in which field pea (<i>Pisum sativum</i> cv 40-10 silage pea), oat (<i>Avena sativa</i> L.cv AC Morgan), and triticale (X <i>Triticosecale</i> Wittmack cv Pika) were grown alone or in combination and managed as GrM or GF. Wheat and tillage fallow served as cropped and uncropped controls, respectively. The tillage fallow-control system was tilled twice in the growing season using a small tractor disc. The intercropped oat was seeded at three densities (50, 100, and 150 plants m-2) to determine whether increasing cereal density stimulated N2-fixation in the field pea.<p> The GrM system was sampled and incorporated (when the field pea was at full bloom) two weeks earlier than the GF system. Consequently, at both sites, all treatments in the GF system consistently yielded more dry matter and accumulated more N than treatments in the GrM system. At the Delisle site, where percent nitrogen derived from the atmosphere (%Ndfa) was compared, increasing cereal density did not increase N2-fixation in both management systems. However, pea in the GF system accumulated more than twice the amount of N (kg ha-1) from fixation as compared to pea in the GrM system, presumably because of the longer growth period.<p> Wheat grown following the GrM treatments produced more biomass and accumulated more N than wheat following the GF treatments. Wheat grown after the monoculture field pea as a GrM had greater yield than all treatments. As well, the GrM system returned more N to the soil than did the GF system. The extra two weeks of growth in the GF system resulted in the extraction of significant amounts of nutrients and probably moisture from the soil, which adversely affected yield and nutrient composition of the following wheat crop.<p> Although organic farmers may lose income in the plough-down year, on a longterm soil sustainability basis, the GrM system is a better option than the GF system as it returns nutrients to the soil, thus providing improved plant biomass, and N accumulation of subsequent crops. However, organic farmers growing GF for hay may benefit from the increased productivity of this system on a short-term basis. Thus, farmers pursuing GF options may need to adopt other means of sustaining soil productivity on a longer term. The tilled fallow-control system resulted in high amounts of biomass and N accumulation by the subsequent wheat crop, probably due to the fact that there were no nutrients taken up in the previous year and moisture was conserved in these treatments. However, this system may have less long-term benefits compared to the GrM regime, as no nutrients are returned through ploughing down a crop.

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