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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.
1

Eficiência agronômica de fontes de manganês, disponibilidade para a soja e distribuição nas frações do solo /

São João, Andréia de Cássia Gomes. January 2006 (has links)
Orientador: Edson Luiz Mendes Coutinho / Banca: Mara Cristina Pessoa da Cruz / Banca: Takashi Muraoka / Abstract: A greenhouse experiment was carried out to evaluate the effects in soil, plant and soybean dry matter yield in function of manganese rates and sources. The distribution of manganese in different fractions was evaluated. A completely randomized design in a factorial arrangement 3x6x3 (soil x rate x Mn source) was used. The soils were classified as Typic Quartzipsamment (soil 1), clayey Typic Haplustox (soil 2) and sandy clay loam Typic Haplustox (soil 3). Mn rates were 0, 5, 10, 20, 40 e 60 mg kg-1 using single superphosphate + Mn (micronutrient incorporated in ordinary superphosphate granulation), "Fritted" Mn and manganese sulphate. The available Mn was determined with Mehlich-1 (M-1) and DTPA. The extractants used to evaluate Mn solubility in fertilizers were: water, 20 g L-1 citric acid and neutral ammonium citrate solutions. The agronomic effectiveness of the manganese sources was calculated using manganese sulphate as reference. Using sequential extraction, the soil Mn was partitioned into exchangeable, organic, amorphous Fe and Al oxides, crystalline Fe and Al oxides and residual forms. Mn fertilization increased Mn content in soybean shoot, regardless to soil and source considered. Dry matter yield depended of Mn initial in soils. In soils 1 and 2, which had low Mn content, occured an increase in soybean dry matter yield. The DTPA and M-1 extractants were efficient to evaluate the Mn availability to soybean. The "fritted" Mn source resulted lower agronomic effectiveness in comparison to SS+Mn and MnSO4...(Complete abstract, acess undermentioned eletronic adress) / Mestre
2

Bário, cádmio, cromo e chumbo em plantas de milho e em Latossolo que recebeu lodo de esgoto por onze anos consecutivos /

Merlino, Luciana Cristina Souza. January 2010 (has links)
Orientador: Wanderley José de Melo / Banca: Cássio Hamilton Abreu Júnior / Banca: Jorge de Lucas Júnior / Resumo: Rico em matéria orgânica e nutrientes, o lodo de esgoto tem despertado interesse na utilização agrícola com o intuito de substituir total ou parcialmente o uso de adubos minerais. Embora a utilização agrícola seja uma alternativa para sua disposição final, o lodo de esgoto pode conter elevadas concentrações de metais pesados, que são elementos potencialmente tóxicos às plantas, aos animais e aos homens, exigindo assim, uma avaliação cuidadosa da sua aplicação continuada ao solo. Nesse sentido, objetivou-se com este estudo avaliar os efeitos da aplicação do lodo de esgoto complementado com K por onze anos consecutivos em Latossolo Vermelho distrófico na produtividade do milho, no fornecimento de nutrientes à cultura, na concentração de Ba, Cd, Cr e Pb na folha para diagnose foliar, planta inteira (parte aérea + raiz) e nos grãos de milho, na distribuição de Ba, Cd, Cr e Pb no perfil do solo e na distribuição dos mesmos metais nas frações do solo (solúvel+trocável, adsorvida à superfície, matéria orgânica, óxidos de manganês, óxidos de ferro amorfo, óxidos de ferro cristalino e residual). O experimento foi desenvolvido em condições de campo, utilizando-se o delineamento experimental em blocos casualizados com 4 tratamentos e 5 repetições. Os tratamentos foram: T1= testemunha (sem lodo de esgoto e com fertilização mineral), T2= 5, T3= 10 e T4= 20 t ha-1 de lodo de esgoto, base seca, complementado com K. As amostras de folha para fins de diagnose foliar, solo, planta inteira e grãos foram obtidas, respectivamente, aos 60, 68, 80 e 123 dias após a emergência das plantas. A utilização do lodo de esgoto complementado com K, por onze anos consecutivos, em Latossolo Vermelho distrófico como fertilizante para a cultura do milho proporcionou produtividade superior a obtida com a fertilização mineral e também, ótima condição nutricional para as ... (Resumo completo,clicar acesso eletrônico abaixo) / Abstract: Rich in organic matter and nutrients, sewage sludge has attracted attention for agricultural use in order to fully or partially replace the use of mineral fertilizers. Although agricultural use is an alternative to its final disposal, sewage sludge may contain high concentrations of heavy metals that are potentially toxic to plants, animals and men, and thus requiring a careful assessment for continuous application to the soil. In this sense, this study aimed to evaluate the effects of eleven annual applications of sewage sludge supplemented with K to a Typic Hapludox to maize productivity, nutrient supply to the plants, Ba, Cd , Cr and Pb concentration in maize diagnosis leaf, plant (aerial part + root) and grains, Ba, Cd, Cr and Pb distribution in the soil profile and the metals distribution in the soil fractions (soluble+exchangeable, surface adsorbed, organic matter, manganese oxides, amorphous iron oxides, crystalline iron oxides and residual fraction). The experiment was developed under field conditions, using a randomized block design with 4 treatments and 5 replications. The treatments want: T1= control (no sewage sludge and with mineral fertilization), T2= 5, T3= 10 and T4= 20 t ha-1 sewage sludge, dried basis, complemented with K. The samples of diagnosis leaf, soil, plants and grains were obtained at 60, 68, 80 and 123 days after seedling emergence, respectively. The sewage sludge supplemented with K utilization for eleven consecutive years to a Typic Hapludox provided maize productivity similar to that achieved with mineral fertilizers and also promoted optimal nutritional condition for the plants, confirming its potential as a source of agricultural nutrients. The rates of 10 and 20 t ha-1 sewage sludge supplemented with K increased soil Ba, Cr and Pb concentration in the topsoil (0-0.10 m), but did not affect Cd. The tested sewage sludge rates did not increase Cd, Cr and ... (Complete abstract click electronic access below) / Mestre
3

Zinco, cádmio e chumbo em plantas de milho e em latossolo tratado com lodo de esgoto por nove anos consecutivos /

Nogueira, Thiago Assis Rodrigues. January 2008 (has links)
Orientador: Wanderley José de Melo / Banca: Marcos Omir Marques / Banca: Cassio Hamilton Abreu Junior / Resumo: As maiores limitações para o uso do lodo de esgoto em áreas agrícolas são os riscos de contaminação do solo com metais pesados e sua possível transferência para a cadeia alimentar. Objetivou-se com este estudo avaliar métodos de extração e frações de Zn, Cd e Pb no solo, o acúmulo destes elementos em plantas de milho cultivadas Latossolo Vermelho eutroférrico no nono ano de aplicação de lodo de esgoto e seus efeitos na produção de matéria seca e na produtividade das plantas. O experimento foi instalado em condições de campo na FCAV/UNESP, Campus de Jaboticabal-SP, em delineamento experimental em blocos casualizados com quatro tratamentos e cinco repetições. Os tratamentos foram: 0,0 (testemunha - fertilização mineral); 45,0; 90,0 e 127,5 t ha-1 de lodo de esgoto, base seca, acumuladas em nove aplicações anuais. As concentrações médias de Cd no solo não variaram em função das doses de lodo e das metodologias estudadas. De forma contrária, as concentrações médias de Zn e Pb no solo, obtidas pela digestão com HClO4 + HF, foram 62,3 e 31,8%, respectivamente, superiores àquelas encontradas pelo ataque com HNO3 + H2O2 + HCl. Porém, quando se avaliou apenas o efeito das doses de lodo, em ambos os métodos de extração, verificou-se diferença entre os tratamentos apenas em relação à concentração de Zn no solo. Os estudos de fracionamento da matéria orgânica e da extração seqüencial de Zn, Cd e Pb indicaram que a maior parte dos metais encontrava-se nas frações com ligações mais estáveis, fração humina (matéria orgânica) e residual (extração seqüencial). Exceto para o Cd, que não foi detectado, os acúmulos de Zn e Pb nas partes das plantas de milho aumentaram com as aplicações de lodo de esgoto. Os teores de metais pesados nos grãos, quando detectados, permaneceram dentro da faixa considerada aceitável para o consumo humano ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Major limitation for using sewage sludge in agriculture is the risk of contaminating the soil with heavy metals and their possible transference the man food chain. The objective of this study was to evaluate the soil content of Zn, Cd and Pb using two methods of extraction (HNO3 + H2O2 + HCl and HClO4 + HF), in parts of maize plants grown in a Typic Eutrorthox soil treated with sewage sludge for nine consecutive years, and the effects on dry matter and grain production. The experiment was carried out under field conditions in the Experimental Farm of UNESP in Jaboticabal, São Paulo, Brazil using a randomized blocks design with four treatments and five replications. The treatments were 0.0 (control - mineral fertilization), 45.0, 90.0 and 127.5 t ha-1 sewage sludge (dry basis) accumulated during nine years. The mean concentrations of Cd in soil were not affected by the rates of sewage sludge and methods. In contrary, the mean concentrations of Zn and Pb in soil extracted by HClO4 + HF were 62.3 and 31.8%, higher than those obtained by HNO3 + H2O2 + HCl respectively. However, when the effect of sewage sludge rates was evaluated, it was verified that only soil Zn concentration was affected by the treatments. The distribution of Zn, Cd and Pb in the soil fractions was strongly associated to the humin fraction (organic matter) and residual fraction (sequential extraction). Except for Cd, that was not detected, the accumulated contents of Zn and Pb in the parts of maize plants were generally affected by the successive applications of sewage sludge to the soil. Grain contents of heavy metals, if detected, were in the interval considered acceptable for human consumption. Sewage sludge and mineral fertilization applied to soil for a long time caused similar effects on dry matter and grain production. / Mestre

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