Mudanças climáticas e seus impactos nas produtividades das culturas do feijão e do milho no Estado de Minas Gerais

• Main Author: Oliveira, Leydimere Janny Cota
• Publication Date: 2007
• Format: Master thesis
• Language: por
• Source: LOCUS Repositório Institucional da UFV
• Download full: http://locus.ufv.br/handle/123456789/5288
• topic: Modelagem; Produtividade potencial; Mudanças climáticas; Modeling; Potential yield; Climatic changes; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::AGROMETEOROLOGIA

Some process-based models, by using the Blackman s equation, the negative exponential, rectangular hyperbole, non-rectangular hyperbole, and the efficient use of the radiation were used as the central part in calculation of the carbon balance in order to estimate the variability of the productivity of both maize and bean crops in some mesoregions at Minas Gerais State, from the historic, meteorological and daily data relative to the period from 1975 to 2004. Some alterations in the productivity of the bean and maize crops were also simulated for the years 2020, 2050 and 2080, compared with the basis- year 2000, by considering the future climatic conditions, fertilization effect from CO2 and the technological advance. To quantify the effect of the climatic conditions on productivity of the crops, daily data projected for the A2 scenery based on the general atmosphere circulation model - HadCM3 were used. A simple empirical relationship was used to calculate the effect of the increasing CO2 concentration on the productivity of the crops. The effect of the technological advance on the future productivity was estimated by the tendency of the historical series of the IBGE productivity data, by considering the period from 1976 to 2004. The objectives of this study were: to calculate the potential productivity of the bean and maize crops for the mesoregions in Minas Gerais State, based on those different models previously mentioned; (b) to compare the results from the different models; and (c) to estimate the potential productivity and the yield gap (difference between the potential and real productivities), by taking into account the scenery A2 in the HadCM3 model, the effects from the CO2 fertilization and the technological advance. The potential productivity calculated by those models rather substantially differed. The percent difference between the model showing the highest productivity estimate and that one showing the minor estimate was 105% for bean and 108% for maize crops. The estimates showed an increased potential productivity in relation to the basis- year 2000, that is, from 35.04% to 114.66% for bean and 40.76% to 92.59% for maize crops, depending either on the estimated year and mesoregion. The technological advance showed to be the most important factor for such an increase. The results for the yield gap showed a decreasing tendency for both crops in all mesoregions, as distinguishing the Triângulo/Alto Paranaíba mesoregion.