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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.
51

Utilização de um algoritmo de caminho mínimo no processo de recolhimento do palhiço da cana-de-açúcar

Silva, Inara Soldera Romano da [UNESP] 16 December 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:24:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-16Bitstream added on 2014-06-13T19:52:21Z : No. of bitstreams: 1 silva_isr_me_botfca.pdf: 1100428 bytes, checksum: 826dc0fb9625c7e450be2699f43ec0bd (MD5) / A atual preocupação com o meio ambiente tem feito com que empresas produtoras de cana-de-açúcar invistam na mudança do sistema de colheita. Essa mudança consiste na redução da queima do canavial na pré-colheita e na utilização do corte mecanizado com cana crua. Porém, a colheita com corte mecanizado torna disponível a biomassa residual e sem as queimadas e com o maior acúmulo do palhiço sobre o solo, criamse condições favoráveis para o aparecimento de parasitas e atraso da brota da cana, comprometendo a próxima safra. Vários autores mostram a viabilidade do uso do palhiço na produção de energia. Pois, além do potencial energético desta biomassa, têm-se como vantagens as questões ambientais, a manutenção de empregos e a substituição dos recursos energéticos de fontes naturais. Mas, as grandes dificuldades ainda encontradas para aproveitamento desse resíduo para geração de energia são o grande número de maquinário envolvido no sistema de coleta deste resíduo e o alto custo que este processo demanda, principalmente o custo com transporte. O presente trabalho tem como objetivo propor aplicações de técnicas matemáticas de otimização para auxiliar o planejamento do recolhimento do palhiço da cana-de-açúcar para aproveitamento na geração de energia, estudando a melhor forma de carregamento dos fardos de palhiço, facilitando o transporte, diminuindo custos e desgastes de maquinários. Para isto, é sugerido o uso de técnicas de agricultura de precisão para mapear o palhiço enfardado, desta forma pode-se definir uma rota para recolher os fardos no campo e transportá-los para o centro de processamento. Para determinação da rota, propõe-se o uso do algoritmo de menor caminho da teoria de grafos, utilizando uma variação do algoritmo de Dijkstra. / The current concern with the environment has made sugar cane growers invest in changing their harvesting system. This change consists of the reduced burning of cane fields before harvesting and the use of mechanized cutting for raw canes. However, mechanized harvesting makes residual biomass available and, without the burning, the major accumulation of crop residue on the ground, creating favorable conditions for the emergence of parasites and delay of new shoots, affecting the next crop. Several authors show the feasibility of using crop residue for energy production. Besides the energy potential of the biomass, there are advantages for the environmental issues, preservation of jobs and the replacement of energy resources from natural sources. But the great difficulties still found in using this residue for power generation are the large number of machinery involved in the collection system of the waste and the high costs of this process, mainly transport costs. This paper aims to propose applications of mathematical optimization techniques to help plan the collection of sugar cane crop residue to be used for power generation, by studying the best way of loading bales of crop residue, making it easy to transport them, therefore reducing costs and wear on machinery. For this, we suggested the use of techniques of Precision Agriculture to map the baled crop residue, which allows you to define a route to pick up the bales in the field and transport them to the processing center. To determine the route, it is proposed to use the shortest path algorithm from graph theory, using a variation of Dijkstra's algorithm.
52

Utilização de um algoritmo de caminho mínimo no processo de recolhimento do palhiço da cana-de-açúcar /

Silva, Inara Soldera Romano da, 1982- January 2009 (has links)
Orientador: Helenice de Oliveira Florentino Silva / Banca: Adriana Cristina Cherri Nicola / Banca: Odivaldo José Seraphim / Resumo: A atual preocupação com o meio ambiente tem feito com que empresas produtoras de cana-de-açúcar invistam na mudança do sistema de colheita. Essa mudança consiste na redução da queima do canavial na pré-colheita e na utilização do corte mecanizado com cana crua. Porém, a colheita com corte mecanizado torna disponível a biomassa residual e sem as queimadas e com o maior acúmulo do palhiço sobre o solo, criamse condições favoráveis para o aparecimento de parasitas e atraso da brota da cana, comprometendo a próxima safra. Vários autores mostram a viabilidade do uso do palhiço na produção de energia. Pois, além do potencial energético desta biomassa, têm-se como vantagens as questões ambientais, a manutenção de empregos e a substituição dos recursos energéticos de fontes naturais. Mas, as grandes dificuldades ainda encontradas para aproveitamento desse resíduo para geração de energia são o grande número de maquinário envolvido no sistema de coleta deste resíduo e o alto custo que este processo demanda, principalmente o custo com transporte. O presente trabalho tem como objetivo propor aplicações de técnicas matemáticas de otimização para auxiliar o planejamento do recolhimento do palhiço da cana-de-açúcar para aproveitamento na geração de energia, estudando a melhor forma de carregamento dos fardos de palhiço, facilitando o transporte, diminuindo custos e desgastes de maquinários. Para isto, é sugerido o uso de técnicas de agricultura de precisão para mapear o palhiço enfardado, desta forma pode-se definir uma rota para recolher os fardos no campo e transportá-los para o centro de processamento. Para determinação da rota, propõe-se o uso do algoritmo de menor caminho da teoria de grafos, utilizando uma variação do algoritmo de Dijkstra. / Abstract: The current concern with the environment has made sugar cane growers invest in changing their harvesting system. This change consists of the reduced burning of cane fields before harvesting and the use of mechanized cutting for raw canes. However, mechanized harvesting makes residual biomass available and, without the burning, the major accumulation of crop residue on the ground, creating favorable conditions for the emergence of parasites and delay of new shoots, affecting the next crop. Several authors show the feasibility of using crop residue for energy production. Besides the energy potential of the biomass, there are advantages for the environmental issues, preservation of jobs and the replacement of energy resources from natural sources. But the great difficulties still found in using this residue for power generation are the large number of machinery involved in the collection system of the waste and the high costs of this process, mainly transport costs. This paper aims to propose applications of mathematical optimization techniques to help plan the collection of sugar cane crop residue to be used for power generation, by studying the best way of loading bales of crop residue, making it easy to transport them, therefore reducing costs and wear on machinery. For this, we suggested the use of techniques of Precision Agriculture to map the baled crop residue, which allows you to define a route to pick up the bales in the field and transport them to the processing center. To determine the route, it is proposed to use the shortest path algorithm from graph theory, using a variation of Dijkstra's algorithm. / Mestre
53

Aditivos antimicrobianos e inclusão de fibra em dietas de milho grão inteiro para bovinos de corte / Antimicrobial feed addtitives and fiber inclusion in whole shelled corn diets fed to beef cattle

Lemos, Barbara Juliana Martins 09 March 2016 (has links)
Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2016-06-15T15:00:53Z No. of bitstreams: 2 Tese - Barbara Juliana Martins Lemos - 2016.pdf: 959267 bytes, checksum: 9f20cc6866e6ccdd38204d892b61882f (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-06-28T11:41:56Z (GMT) No. of bitstreams: 2 Tese - Barbara Juliana Martins Lemos - 2016.pdf: 959267 bytes, checksum: 9f20cc6866e6ccdd38204d892b61882f (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-06-28T11:41:56Z (GMT). No. of bitstreams: 2 Tese - Barbara Juliana Martins Lemos - 2016.pdf: 959267 bytes, checksum: 9f20cc6866e6ccdd38204d892b61882f (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2016-03-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The objective of this study was evaluate the effects of antimicrobial feed additives and inclusion of pelleted sugarcane crop residue (SCR) as a fiber source in whole shelled corn (WSC)-based finishing diets (85% WSC + 15% pelleted concentrate, DM basis) on growth performance, nutrients digestibility, rumen fermentation and eating behavior of zebu cattle. Growth performance trials were conducted in randomized block design, and metabolical trials were conducted in Latin Square design using ruminally fistulated steers. In the antimicrobial feed additives studies, 100 bulls were fed for 101 d in Exp. 1 to evaluate the treatments M30 (30 mg of monensin [M]/kg DM), V25 (25 mg of virginiamycin [V]/kg DM), M20V25 (M 20 mg/kg DM + V 25 mg/kg DM), F4 (4.4 mg of flavomycin [F]/kg DM), and M20F2 (M 20 mg/kg DM + F 2.2 mg/kg DM); and in the Exp. 2 (Latin Square 7 × 7) were evaluate the same 5 treatments of Exp. 1 plus 2 additional treatments: M30V25 (M 30 mg/kg DM + V25 mg/kg DM) and M20F4 (M 20 mg/kg DM + F 4.4 mg/kg DM). In the SCR studies, 80 bulls were fed diets with 0, 3, 6, and 9% SCR (DM basis; SCR-0, SCR-3, SCR-6, and SCR-9, respectively) for 103 d in Exp. 1; and in the Exp. 2 (5 × 5 Latin Square) were evaluated the inclusion of 0, 3, 6, 9 and 12% of SCR (DM basis; SCR-0, SCR-3, SCR-6, SCR-9, and SCR-12, respectively). In the antimicrobial feed additives studies growth performance (final BW, ADG in live weight basis, DMI, and G:F), carcass characteristics (HCW, ADG in carcass basis, carcass transfer, dressing percent, and 12th-rib-fat), apparent total tract DM, OM, CP, and NDF digestibility were similar among treatments. There were no treatment effects and no interaction of treatment × time in rumen fermentation responses (ruminal pH, rumen ammonia nitrogen, number of protozoa, and VFA). In the WSC study, inclusion of SCR linearly increased daily DMI up to 25% (P = 0.01). Dry matter intake, as percentage of BW, increased (P = 0.01) 0.06 percentage units with each 1% inclusion of SCR. Over the entire finishing period (d 0 to 103), there were trends for linearly increase final BW up to 3.3% (P = 0.10), and ADG up to 10.7% (P = 0.07) in response to dietary SCR levels, consequentially G:F tended (P = 0.07) to linearly decrease up to 10.2% with inclusion of SCR compared with CTL diet. Apparent total tract digestibility linearly decreased (P < 0.01) 30% for DM, 28% for OM, 45% for CP, and 61% for NDF, from CTL for SCR-12. No treatment effect and no interaction of treatment × time were observed on ruminal pH, concentrations of rumen ammonia nitrogen and VFA. Time spent eating, eating rate, and meal frequency were not affected by inclusion of SCR up to 12%. There was a quadratic response on meal size (P = 0.04). In summary, feeding isolated or combined antimicrobial feed additives to zebu cattle resulted in similar responses. Pelleted SCR seemed to be low fermentable and non-effective to stimulate rumination by cattle fed WSC-based finishing diet. / Objetivou-se avaliar os efeitos de aditivos antimicrobianos e a inclusão do resíduo peletizado da cultura de cana de açúcar (SCR) como fonte de fibra em dietas com milho grão inteiro (WSC; 85% WSC + 15% concentrado peletizado) sobre o desempenho, digestibilidade dos nutrientes, fermentação ruminal e comportamento ingestivo de novilhos zebuínos. Os experimentos de desempenho foram conduzidos em delineamento de blocos cazualizados e experimentos de metabolismo foram conduzidos em delineamento em Quadrado Latino usando novilhos castrados fistulados no rúmen. No estudo de aditivos antimicrobianos, no Exp. 1 foram utilizados 100 novilhos não castrados alimentados durante 101 dias para avaliar os tratamentos M30 (30 mg de monensina [M]/kg de DM), V25 (25 mg de virginiamicina [V]/kg de DM), M20V25 (M 20 mg/kg DM + V 25 mg/kg DM), F4 (4.4 mg de flavomicina [F] /kg de DM), e M20F2 (M 20 mg/kg DM + F 2.2 mg/kg DM); no Exp. 2 (Quadrado Latino 7 × 7) foram estudados os mesmos 5 tratamentos do Exp. 1 mais 2 tratamentos adicionais: M30V25 (M 30 mg/kg DM + V25 mg/kg DM) e M20F4 (M 20 mg/kg DM + F 4.4 mg/kg DM). Nos estudos com SCR, 80 novilhos não castrados foram alimentados com dietas contendo 0, 3, 6 e 9% de SCR (base de DM; SCR-0, SCR-3, SCR-6 e SCR-9, respectivamente) durante 103 dias; no Exp. 2 (Quadrado Latino 5 × 5) foram avaliadas inclusões de 0, 3, 6, 9 e 12% de SCR (base de DM; SCR-0, SCR-3, SCR-6, SCR-9 e SCR-12, respectivamente). Nos estudos com aditivos antimicrobianos, o desempenho (final BW, ADG em peso corporal, DMI e G:F), as características de carcaça dos novilhos (HCW, ADG em carcaça, rendimento do ganho em carcaça, rendimento de carcaça e espessura de gordura na 12ª costela), a digestibilidade aparente da DM, OM, CP e NDF no trato total foram similares entre os tratamentos. Não houve efeito de tratamento e interações de tratamento × tempo nas características da fermentação ruminal (pH ruminal, nitrogênio amoniacal, contagem de protozoários e VFA). No estudo da SCR, a DMI aumentou linearmente em até 25% (P = 0.01). O consumo de DM calculado como % do BW aumentou (P = 0.01) 0.06 unidades percentuais a cada 1% de inclusão de SCR. Ao longo de todo o período de confinamento (dia 0 ao dia 103) foram observadas tendências de aumento linear de até 3.3% do BW final (P = 0.10) e 10.7% do ADG (P = 0.07), consequentemente houve tendência de reduzir linearmente a G:F em até 10.2% (P = 0.07) com a inclusão da SCR em comparação à dieta CTL. A digestibilidade aparente dos nutrientes diminuiu linearmente (P < 0.01) em até 30% para DM, 28% para OM, 45% para CP e 61% para o NDF, do CTL para SCR-12. Não foram observados efeitos de tratamento e interação tratamento × tempo no pH ruminal, concentração de nitrogênio amoniacal e VFA. Tempo gasto alimentando, taxa e frequencia de alimentação não foram afetados pela inclusão de até 12% de SCR. Houve uma resposta quadrática no tamanho da refeição (P = 0.04). Em conclusão, o fornecimento de aditivos antimicrobianos isolados ou combinados para novilhos zebuínos resultaram em respostas similares. A SCR peletizada teve baixa digestibilidade e não foi efetiva para estimular a ruminação do gado alimentado com dieta de milho grão inteiro.
54

Emissão de gases de efeito estufa do solo devido à remoção de quantidades de palha de cana-de-açúcar e à adubação nitrogenada / Greenhouse gas emission due to sugarcane straw removal and nitrogen fertilization

Ana Luisa Soares de Vasconcelos 02 December 2016 (has links)
A palha de cana-de-açúcar tem sido uma importante matéria prima para aumentar a produção de bioenergia no Brasil. Porém a dinâmica das emissões de gases de efeito estufa no campo devido à prática de remoção de palha ainda não é totalmente compreendida. O objetivo deste trabalho foi quantificar as emissões de GEE do solo devido à remoção da palha de cana-de-açúcar com e sem adição de nitrogênio. Foram realizados dois experimentos com câmaras amostrais de gás mantidas em condições naturais com quatro tratamentos: sem palha, 3, 6 e 12 Mg ha-1, os quais equivalem as intensidades de 100, 75, 50 e 0% de remoção. O primeiro foi conduzido por 180 dias sem adição de N e o segundo experimento conduzido por 100 dias, foi adicionado 80 kg ha-1 de N no sulfato de amônio e 32 kg ha-1 de N na vinhaça. Conjuntamente ao experimento 1, foi conduzido um ensaio de decomposição com as mesmas quantidades de palha limitadas por caixas plásticas sem fundo (0,3 x 0,5 m). No Experimento 1 a presença de palha aumentou 35 - 45% os fluxos acumulados N2O e CO2 em relação ao solo descoberto. O influxo de CH4 aumentou 40% na presença total de palha (12 Mg ha-1) em relação ao sem palha. O fator de emissão de N2O encontrado para a palha em decomposição foi de 0,02%. No Experimento 2 ocorreu uma intensificação das emissões devido à adubação nitrogenada, com isso as emissões em razão das quantidades de palhas não foram significantes. O fator de emissão médio foi de 0,42%. Os resultados indicam que a palha, sem N, possui um efeito na emissão de GEE e, que para manter o estoque de C do solo, é necessário a manutenção de pelo menos 6 Mg ha-1 para compensar as perdas de CO2 por respiração. Este trabalho contribuirá para os cálculos de pegada de carbono do bioetanol e na decisão da usina sobre a intensidade de remoção de palha de cana-de-açúcar para a produção de energia e etanol 2G / Sugarcane straw has been point out as an important feedstock to increase bioenergy production in Brazil However, the field greenhouse gas (GHG) emission dynamic due straw removing management is not completely understood yet. Two experiments were conducted with gas sampling chambers that was kept under natural conditions with four treatments: bare soil, 3, 6 and 12 Mg ha-1, which is approximately the equivalent of the 100, 75, 50 and 0 % intensities of removing. The first was conducted for 180 days without the N addition and the second experiment was conducted for 100 day and its was added 80 kg ha-1 N in ammonium sulfate and 32 kg ha-1 N in the vinasse. Parallely to the experiment 1, a decomposing trial was conducted with the same straw amounts in a side limited bottomless plastic boxes (0.3 x 0.5 m). In Experiment 1, the presence of straw increased 35-45% the N2O and CO2 accumulated flux compared to the bare soil. While the influx of CH4 increased by 40% in the maximum straw amount (12 Mg ha-1) compared to zero. The N2O emission factor found for the straw decomposition was 0.02%. In Experiment 2 occurred an intensification of emissions due to nitrogen fertilization which raised the average emission factor for 0.42%. Thus emission due straw quantities were not significant. The results indicate that the straw without N has an effect of GHG emissions, and in order to maintain the C stock in soil is need keep at least 6 Mg ha-1 of straw to compensate for the loss of CO2 thru respiration. This work will contribute to the bioethanol carbon footprint calculation and in the grower decision taking of straw removing intensity for energy and 2G ethanol
55

Nitrogênio em videira: Recuperação, acumulação e alterações na produtividade e na composição da uva / Nitrogen in grapevine: recovery, acumulation and alterations in the yeld and grape composition

Brunetto, Gustavo 20 February 2008 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / The rate of nitrogen (N) in grapevines in the Rio Grande do Sul (RS) State, Southern Brazil, is established considering N content in leaves or leaves petioles and yield expectation limits. Once N fertilization needs have been diagnosed, the N is applied in indefinite times. However, N fertilization recommendations don t consider the impact of N fertilization in the yield, the consequences on grape composition and the contribution of N of crop residues to mineral nutrition of grapevines. The objective of this work was to estimate the recovery and accumulation of N in grapevines and the effect in the yield and grape composition. Three studies were carried on. Study 1, recovery, distribution and accumulation of N fertilizer was studied, in Cabernet Sauvignon grapevines, located at Bento Gonçalves city, area of the Serra Gaúcha (experiment 1), and Santana do Livramento city, area of the Campanha (experiment 2), in RS, Southern Brazil. In the experiment 1 and 2 the plants were fertilized with 15N in four forms and, when grapes were mature, plants were fractionated, oven-dried, weighted and analysed for total N and 15N enrichment. Study 2, grape yield and composition of grapevines treated with different amounts of N were studied, in the vineyards of the Study 1. Grapes were collected when ripe and yield was evaluated. Must soluble solids, pH, total acidity, tartaric acid, malic acid, total phenols, anthocyanins and N ammonia were evaluated in part of the berries. The remaining berries were triturated and total N, P, K, Ca and Mg were evaluated. Study 3, decomposition and nutrient release by aerial organs of Lolium perenne (LP) and Trifolium repens (TR) (experiment 1), and grapevines uptake of the N derived from decomposing material (experiment 2) were studied in Chardonnay grapevines located at the experimental Station of the University of Bologna, Italy. In experiment 1, 2 g (DW) of 15N-labelled litter of LP and TR were placed into litter bags which were placed on the vineyard soil surface. Collection of bags LP and TR was performed 8 (June) and 16 (August) weeks from the deposition. Remaining biomass, 15N, N, C, P, K, Ca, Mg and S concentrations were determined. In experiment 2, 30 g plant-1 of dry litter of LP and TR were placed on the herbicided soil under the grape plants. Grapevine leaves were collected 8 and 16 weeks from litter deposition; after 16 weeks, one year (including bunches) and two years shoots were collected, oven-dried, weighted and analysed for total N and 15N enrichement. Results showed that the absorbed N is distributed and accumulated especially in leaves and that most of the N found in the plant was not derived from the fertilizers but from the organic matter already present in the soil. However, N fertilization increased grape yield in the Serra Gaúcha grapevines. The rate can be split 25% at the beginning of bud burst + 25% at bud burst + 25% at flowering + 25% at growth berries; 50% at the beginning of bud burst + 50% at bud burst and 50% at flowering + 50% at growth berries. Moreover, N fertilization altered the grape composition, especially decrease the amount of anthocyanins. LP and TR residues decomposed at the same rate, but nutrient release was different between the two species and varied according with mineral element. The amount of N that grapevines recovered from the decomposing litter was low and similar for LP and TR residues. / No Rio Grande do Sul (RS), a dose de nitrogênio (N) para a videira é definida a partir do seu teor total na folha inteira ou no pecíolo, e na expectativa de produção. Quando diagnosticada a necessidade de aplicação, recomenda-se o seu parcelamento em épocas incertas. Entretanto, essa recomendação não infere informações sobre o impacto do N aplicado na produção e na composição da uva. Também não se considera a contribuição do N dos resíduos de plantas de cobertura depositados na superfície do solo. O presente trabalho teve como objetivo estudar a recuperação e acumulação de N em videiras e seu efeito na produtividade e na composição da uva e do mosto. Foram conduzidos três estudos: Estudo 1, realizado para estimar a recuperação, distribuição e a acumulação de N aplicado ao solo pela videira. Esse foi composto por dois experimentos: Experimento 1, implantado em um vinhedo de Cabernet Sauvignon na Embrapa Uva e Vinho, Bento Gonçalves (RS), e o experimento 2, instalado na Empresa Pernod Ricard Brasil/Almadén, Santana do Livramento (RS). Nos experimentos 1 e 2 as videiras foram submetidas à aplicação de uma dose de N com 3% de átomos de 15N, em quatro modos de parcelamento. Na maturação da uva, as plantas foram colhidas, fracionadas, secas, determinada a matéria seca (MS) e analisado os totais de N e 15N. O Estudo 2 foi realizado para avaliar a produtividade e a composição da uva e do mosto, em videiras submetidas à aplicação de N. O Estudo 2 foi formado por dois experimentos: Experimento 1, implantado no vinhedo do experimento 1 do Estudo 1, as videiras receberam cinco doses de N e o experimento 2, instalado no vinhedo do experimento 2 do Estudo 1, as videiras foram submetidas à aplicação de seis doses de N. Nos experimentos 1 e 2 a uva foi colhida, determinada a produção e no seu suco avaliado os sólidos solúveis totais, o pH, a acidez total, o ácido tartárico e málico, os polifenóis totais, as antocianinas e o N amoniacal. Além disso, na baga foram analisados os totais de N, P, K, Ca e Mg. O Estudo 3 foi realizado para determinar a contribuição de N derivado da decomposição de resíduos de azevém (Lolium perenne) e trevo branco (Trifolium repens) para a videira. Esse compreendeu dois experimentos instalados em vinhedo de Chardonnay, em Bologna, Itália. No experimento 1, os resíduos de azevém perene e de trevo branco foram colocados no interior de bolsas teladas e depositados no solo. Ao longo do ciclo das videiras as bolsas teladas foram coletadas, determinada a MS remanescente e analisado os totais de 15N, N, C, P, K, Ca, Mg e S. No experimento 2, os resíduos das espécies foram colocados na superfície do solo e na maturação da uva as videiras foram colhidas, fracionadas, secas, determinado a MS e analisado os totais N e 15N. Os resultados obtidos mostram que o N adicionado e absorvido no ano é distribuído e acumulado, preferencialmente, nas folhas, mas a maior parte do N presente na videira é derivada de outras formas, que não a do fertilizante. Entretanto, existe aumento na produção quando da aplicação de N na Serra Gaúcha, podendo a dose ser parcelada 25% no início da brotação+25% na brotação+25% na floração+25% no crescimento das bagas; 50% no início da brotação+50% na brotação e 50% na floração+50% no crescimento das bagas. A aplicação de N altera a composição da uva, especialmente, diminui a quantidade de antocianinas no mosto. Os resíduos de azevém perene e trevo branco depositados na superfície do solo são decompostos com a mesma taxa no ciclo vegetativo e produtivo da videira, porém liberam nutrientes em taxas diferentes. No entanto, isso tem pouca importância, pois as plantas recuperam porcentagens pequenas e iguais de N derivado dos resíduos das duas espécies.
56

Long-term effects of tillage and residues on selected soil quality parameters

Callum, Ian R. January 2001 (has links)
No description available.
57

Influence of a legume green manure crop on barley straw/stubble decomposition, and soil nitrogen retention and availability

Kapal, Debbie B. January 2008 (has links)
The incorporation of cereal straw/stubble often immobilises nitrogen (N). This can help conserve N in soil in organic forms, thus reducing loss through leaching over dormant winter periods. However, N-depressions that arise during decomposition can reduce crop yield. The inclusion of a legume green manure can supply fixed-N, thus alleviating the low N availability to crops. In this study, the effect of lupin (Lupinus angustifolius L.) green manure incorporation on barley (Hordeum vulgare L.) straw/stubble decomposition, and N availability was investigated. A field experiment was used to determine the effects of the green manure on decomposition. Decomposition of straw/stubble was monitored using the litterbag technique. Following green manure incorporation, soil cores were incubated in a glasshouse to determine mineral-N availability. Though not significant, the inclusion of lupin green manure seemed to increase the decomposition of straw/stubble during the growth period, then slowing it after its incorporation at 110 d. This was described by a logarithmic pattern of loss of - 4.97 g AFDW residue day⁻¹, with 60% remaining after 140 d. Treatments without lupin had a linear decomposition of - 0.12 g AFDW residue day⁻¹, with 49% remaining after 140 d. The loss of cellulose confirmed the differences in decomposition with the inclusion of lupin resulting in 2.79% less cellulose remaining in straw/stubble after 140 d compared to its exclusion. Lupin significantly increased pot oat N uptake and DM yield by 55 % and 46 %, respectively, compared to its exclusion. However, this effect was not observed in field sown wheat yields and the soil mineral-N measurements made. This study showed that the potential of lupin to increase straw/stubble decomposition by improving the retention and availability of N, leading to long-term yield benefits, needed further investigation.
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Trinexapac-ethyl and open-field burning in creeping red fescue (Festuca rubra L.) seed production in the Willamette Valley

Zapiola, Maria Luz 22 October 2004 (has links)
Open-field burning has been an effective, economical, and widespread method of post-harvest residue management in creeping red fescue seed production in the Willamette Valley since the late 1940s. However, the use of field burning has been legislatively restricted due to air quality and safety issues. The foliar-applied plant growth regulator trinexapac-ethyl (TE), commercialized in the USA as Palisade, has been accepted by producers as a yield enhancing agent and is considered here as an alternative to open-field burning over a four-year period. The effects of open-field burning versus mechanical removal (flailing) of post-harvest residue, and spring versus fall applications of TE on seed yield, dry matter partitioning, and seed yield components were evaluated in a split-plot design. The response to the different treatment combinations differed across years. The young stand responded with a seed yield increase to spring TE applications, regardless of residue management treatment. However, as the stand aged, field burning became critical for maintaining high yields and, in 2003 and 2004, only spring TE applications resulted in seed yield increases in burned plots. The higher potential seed yield achieved in burned plots over flailed plots, as a result of a higher number of panicles per unit area and spikelets per panicle, was critical for maintaining high seed yields as the stand aged. Spring applications of TE, further increased seed yield over the untreated check by increasing the number of florets per spikelet, reducing fertile tiller height and lodging and consequently, favoring pollination and fertilization of the florets. Late spring TE applications also increased 1000-seed weight in 2003 and 2004. Although spring applications of TE were a promising alternative to open-field burning early during the life of the stand, as the stand aged they did not increase seed yield on flailed plots. Fall TE applications did not have a consistent effect on seed yield, dry matter partitioning or seed yield components, and were found not to be a viable management practice. / Graduation date: 2005
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Investigation into the characteristics and possible applications of biomass gasification by-products from a downdraft gasifier system

Melapi, Aviwe January 2015 (has links)
Biomass gasification has attracted the interest of researchers because it produces zero carbon to the atmosphere. This technology does not only produce syngas but also the byproducts which can be used for various application depending on quality.The study conducted at Melani village in Alice in the Eastern Cape of South Africa was aimed at investigating the possible applications of the gasification byproducts instead of being thrown away. Pine wood was employed as the parent feedstock material for the gasifier. Biomass gasification by-products were then collected for further analysis. The studied by-products included tar(condensate), char, soot and resin. These materials were also blended to produce strong materials.The essence of the blending was to generate ideal material that is strong but light at the same time.The elemental analysis of the samples performed by CHNS analyser revealed that carbon element is in large quantities in all samples. The FTIR spectra showed almost similar results for all the studied samples, since the samples are end products of lignocellulosegasification. SEM gave the sticky images of resin as well as porous char structures. Char showed a higher heating value of 35.37MJ/Kg when compared to other by-products samples.

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