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São Carlos 2009 AGRADECIMENTOS Em primeiro lugar a Deus, por ter me dado fé e perseverança nos momentos mais difíceis desta jornada, Se manifestando até nas menores realizações alcançadas; Ao Dr. Ladislau Martin Neto, pela oportunidade, orientação, imensuráveis amizade, apoio, estímulo e incansáveis reuniões e conversas. Meus profundos agradecimentos; Ao Dr. Wilson Tadeu Lopes da Silva e Dr. Marcelo Luiz Simões pelas preciosas colaborações e observações; Á minha namorada Thalita, pela cumplicidade e momentos de carinho durante todos esses anos;À Embrapa Instrumentação Agropecuária por toda excelente infra-estrutura, pela prestatividade do pessoal e salutar ambiente de trabalho;Ao Renê, pelo seu incansável auxílio nas atividades laboratoriais;Ao Valentim, pelo auxílio nas impressões de trabalhos;Ao James e Seu Roque pelo suporte prestado durante a coleta das amostras no campo experimental de Lins;A meus pais, pelos inúmeros e incansáveis conselhos e direcionamentos.A todos os demais que indiretamente contribuíram para a realização deste trabalho.

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Weed control methods in coffee crops can significantly influence carbon (C) stocks of soil humic substances. The aim of this study was to evaluate C stocks in an experimental coffee crop submitted to conservation agriculture for weed control between coffee rows. The study was carried out in a very clayey Dystroferric Red Latosol, Londrina, Paraná state (23°21’30” S; 51°10’17” W), cultivated with cultivar Mundo Novo IAC 379-19. In 2008, the experiment was established as randomized block design with four replicates within split-split plot scheme. Seven weed control methods between coffee rows were considered (hand weeding; portable mechanical mower; herbicides application; two cover crops; weed check and spontaneous). In September 2013, coffee shrub pruning was conducted and residues were distributed along inter rows. The weed control methods were considered as the main-plot factor and sampling period (March 2014 and February 2015) as the split-plot. Soil samples were collected at the center of the inter rows at four depth increments. C stocks evaluation included total organic carbon determination by chromic acid wet oxidation. Humic substances were characterized by UV-Vis spectroscopy. Most of the considered weed control methods did not affect organic carbon storage in 0 – 40 cm layer, nevertheless led to increase at topsoil. In 2015, the humin fraction C stock was 54 % higher at superficial layer than subsequent depth, presenting 39 % average increase at the 2014/2015 interval. Although C stocks from humic and fulvic acids did not vary, more conjugated/condensed characteristic for the fulvic fraction was observed.

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Humic substances (HS) comprise the passive element in soil organic matter (SOM), and represent one of the soil carbon pools which may be altered by different cover crops and weed control methods. This study aimed to assess HS distribution and characteristics in an experimental coffee crop area subjected to cover crops and cultural, mechanical, and chemical weed control. The study was carried out at Londrina, in the state of Paraná, southern Brazil (23°21'30" S; 51°10'17" W). In 2008, seven weed control/cover crops were established in a randomized block design between two coffee rows as the main-plot factor per plot and soil sampling depths (0-10 cm, 10-20 cm, 20-30 cm and 30-40 cm) as a split-plot. HS were extracted through alkaline and acid solutions and analyzed by chromic acid wet oxidation and UV-Vis spectroscopy. Chemical attributes presented variations in the topsoil between the field conditions analyzed. Cover crop cutting and coffee tree pruning residues left on the soil surface may have interfered in nutrient cycling and the humification process. Data showed that humic substances comprised about 50 % of SOM. Although different cover crops and weed control methods did not alter humic and fulvic acid carbon content, a possible incidence of condensed aromatic structures at depth increments in fulvic acids was observed, leading to an average decrease of 53 % in the E 4 /E 6 ratio. Humin carbon content increased 25 % in the topsoil, particularly under crop weed-control methods, probably due to high incorporation of recalcitrant structures from coffee tree pruning residues and cover crops.

A alface é a principal hortaliça folhosa comercializada e consumida pela população brasileira devida, principalmente, à facilidade de aquisição e à produção durante o ano todo. Com este trabalho objetivou-se analisar e comparar valores nutricionais da cultura hidropônica à cultura convencional de alface. O experimento foi conduzido em casa de vegetação com alface do tipo “crespa”, em sistema hidropônico (NFT), instalado em três casas de vegetação, o período de condução do experimento foi de junho a outubro de 2013 no município de Serranópolis do Iguaçu. Para que fosse possível o estudo comparativo da tecnologia hidropônica ao cultivo convencional, foi selecionada a estufa de alface convencional no mesmo município. O cultivo hidropônico preconizado neste trabalho utilizou a Técnica do Fluxo Laminar de Nutrientes (NFT). O cultivo hidropônico em sistema NFT, todas as cultivares avaliadas apresentaram boa produtividade. Observa-se quem as alfaces hidropônicas apresentam uma carga superior de macro e micronutrientes se comparada à convencional.