Impacto e projeção de séries meteorológicas na safra de milho em Minas Gerais

• Ano de defesa: 2008
• Autor(a) principal: Amorim, Marcelo Cid de
• Orientador(a): Costa, Luiz Cláudio
• Banca de defesa: Leal, Brauliro Gonçalves , Costa, José Maria Nogueira da
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Meteorologia Agrícola
• Departamento: Agrometeorologia; Climatologia; Micrometeorologia
• País: BR
• Palavras-chave em Português: Milho; Mudanças climáticas; Minas Gerais
• Palavras-chave em Inglês: Corn; Climate change; Minas Gerais
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::AGROMETEOROLOGIA
• Link de acesso: http://locus.ufv.br/handle/123456789/1493

The state of Minas Gerais is the third largest producer of corn in Brazil. Being that the corn is little tolerant to adverse climate conditions, principally during the pollination and grain formation periods, this factor has caused large variations in yield from year to year, especially in the subregions of Jequitinhonha (MR04), Triângulo Mineiro and Alto Paranaíba (MR11) located in the state of Minas Gerais. The objective of this work was to evaluate possible impacts on the corn growth period, under both current and warming conditions on a subregional scale, considering the environment (soils) and technological effects such as chemical fertilizing and genetically modified crops. The systemized meteorological variables used for the climate component were: incident solar radiation, wind speed, total precipitation, maximum and minimum temperatures structured in observed series (INMET), during the corn growing periods of 1971/1972 to 2003/2004. The predicted series, from 1991 to 2020, were simulated based on synthetic (CLIMGEN) and dynamic (ECHAM5/MPI-OM) data. Concentrations of CO2 in the atmosphere were measured annually by the NOAA and projections were made by the IPCC scenario A1B. The present study used the CERES-MAIZE model to estimate corn yields, including the Support System for Agrotechnology Transfer (DSSAT v.4.5) opposing the simulated values officially registered by EMATER (MG)/IBGE/CONAB. Current regional technological advances were established using the yield gap analysis. Plant response to the future environmental conditions were determined by the biometeorological impacts on corn which included the estimation of the number of days without rain (NDSC), total precipitation,transpiration, evapotranspiration of the crop, degree-days, cycle duration, maximum foliar area index and the harvest index (IC) during the BR201 crop cycle. With respect to the technological effect of chemical fertilizing, even minimal fertilization had a significant on yields. However, in dry regions or during drought short periods, fertilization is not recommended due to its osmotic characteristic. Atmospheric CO2 showed to be stable in the simulations. According to the results, there was a tendency of short harvests from year to year in the meteorological records provided by the dynamic series, including the potential yield. The impact on the subregions was, principally a consequence of the elevation in minimal temperature and reduction in precipitation, both during the critical period and the overall corn cycle. In general, the synthetic meteorological series preserved the present tendencies in the future. Therefore, when evaluating the biometeorological impacts on the BR201 species, it was noted that in general a reduction in the vegetative cycle due to the elevation of the degree-day and decrease in rainfall both in the critical phase and overall cycle, the transpiration, maximum foliar area index and harvest index. The tendency for atmospheric CO2elevation in projections made by IPCC-AR4 and systemized in the ECHAM5/MPI-OM model will produce an economically unfavorable environment in the state of Minas Gerais, and in poorer of more vulnerable regions, a collapse of the production system.