Engenharia Agrícola - Artigos

URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11739

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Data inicial: 2010Data final: 2011Assunto: search.filters.subject.Amazon region

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Agora exibindo 1 - 2 de 2
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    Greenhouse gas induced changes in the fire risk in Brazil in ECHAM5/MPI-OM coupled climate model
    (Climatic Change, 2011-05) Justino, Flavio; Mélo, A. S. de; Sediyama, G. C.; Machado, J. P.; Setzer, A.; Sismanoglu, R.; Ribeiro, G. A.; Sterl, A.
    Vegetation fires are the second largest source of greenhouse gas emissions to the atmosphere. The reduction of the climatic impact of these emissions is related to the vegetation susceptibility to fire (fire risk), as well as to the understanding of possible implications of changes in atmospheric circulation on fire risk in the near-future. This study evaluates the environmental susceptibility to fire occurrence based on a Potential Fire Index (PFI). Two climate simulations from the ECHAM5/MPI-OM climate model have been used to calculate the PFI: present day (1980–2000) and an experiment for the end of the twenty-first century (2080–2100). The results indicate that the proposed PFI methodology could properly reproduce the areas with the highest fire incidence under present conditions. Moreover, it was found that under greenhouse warming conditions the PFI foresees an increase in the fire risk area, particularly for the Amazon region. We concluded, furthermore, that changes of vegetation predicted to occur in the future lead to substantial modifications in the magnitude of the PFI, and may potentially extend the length of the fire season due to induced longer drought periods as compared to current conditions.
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    Simulation of soybean growth and yield under northeastern Amazon climatic conditions
    (Pesquisa Agropecuária Brasileira, 2011-04-04) Ribeiro, Aristides; Souza, Paulo Jorge de Oliveira Ponte de; Farias, José Renato Bouças; Abreu, José Paulo Mourão de Melo e; Rocha, Edson José Paulino da; Botelho, Marcel do Nascimento; Sousa, Adriano Marlisom Leão de
    The objective of this work was to parameterize, calibrate, and validate a new version of the soybean growth and yield model developed by Sinclair, under natural field conditions in northeastern Amazon. The meteorological data and the values of soybean growth and leaf area were obtained from an agrometeorological experiment carried out in Paragominas, PA, Brazil, from 2006 to 2009. The climatic conditions during the experiment were very distinct, with a slight reduction in rainfall in 2007, due to the El Niño phenomenon. There was a reduction in the leaf area index (LAI) and in biomass production during this year, which was reproduced by the model. The simulation of the LAI had root mean square error (RMSE) of 0.55 to 0.82 m^2 m^-2, from 2006 to 2009. The simulation of soybean yield for independent data showed a RMSE of 198 kg ha^-1, i.e., an overestimation of 3%. The model was calibrated and validated for Amazonian climatic conditions, and can contribute positively to the improvement of the simulations of the impacts of land use change in the Amazon region. The modified version of the Sinclair model is able to adequately simulate leaf area formation, total biomass, and soybean yield, under northeastern Amazon climatic conditions.