Carlos Rodrigues Pereira

Expolinear model on soybean growth in Argentina and Brazil

Predicting crop growth and yield with precision are one of the main concerns of the agricultural science. For these purpose mechanistic models of crop growth have been developed and tested worldwide. The feasibility of an expolinear model for crop growth was evaluated on predicting growth modification on soybean (Glycine max L. Merrill) of determined and undetermined growth cultivars, submitted to water restrictions imposed on different phenological stages. An experiment was carried out in Azul/Argentina and in Vicosa/Brazil during the growing seasons (1997/1998, 1998/1999 and 2002/2003). The expolinear model was adjusted to the dry-matter data obtained from each treatment. The model showed sensibility of Rm (maximum relative growth rate of the culture - g g-1 day-1) to variation in air temperature; of Cm (maximum growth rate of the culture - g m-2 day-1) to solar radiation and of Tb (lost time -day) to water stress. Cm values were higher without water restriction presenting, in both countries, a direct correlation with solar radiation. Without water restrictions, Rm values were lower when the average air temperature during the cycle was lower. It was observed that under water stress the culture had a bias to present higher Rm values. Tb was lower in the irrigated treatments than in those with water deficits. The analysis of the outputs clearly shows the feasibility of the expolinear model to explain the differential growth rates of soybean as a consequence of climatic conditions.

Avaliação da biomassa de raízes finas em área de empréstimo submetida a diferentes composições de espécies

The behavior of root system in the process of soil construction in degraded areas varies among individuals, species and communities. To evaluate this behavior, a study was conducted in a region named Costa Verde, municipal district of Itaguai, State of Rio de Janeiro, using subsoil from a reclamation area with similar soil-climatic characteristics subjected to three different species compositions that can influence the ecosystem and soil construction. There was no difference for total fine root production at 30 cm depth, although the vegetation with the greatest functional and species diversity most contributed to ecosystem construction.

Analysis of the major world strategies for reducing the emission of greenhouse gases generated by public and private transport

The World Health Organization (WHO) estimates that, worldwide, three million people die annually due to the effects of air pollution. This represents a tripling of deaths per year result from automobile accidents. With the increasing technological advancement becomes very important to monitor levels of air pollutants. Thus, in the Japanese city of Kyoto, was established called the Kyoto Protocol effectively in 1997, where Eighty-four countries were willing to join and signed, thereby committing itself to implement measures aiming to reduce greenhouse gas emissions weathering. The relationship of the transportation sector to climate change and global warming have sparked unimaginable experiences about twenty years. Currently scientists are finding themselves faced with daunting environmental phenomena and clearly visible to the whole planet, directly or indirectly, and anticipate in the search for a model of strategic action that minimizes the effect of climate over land and ensures the survival of this and future generations.

TEOR DE NITROGÊNIO, ÍNDICES DE ÁREA FOLIAR E DE COLHEITA, NO MILHO, EM FUNÇÃO DA ADUBAÇÃO NITROGENADA, EM SOLO DE VÁRZEA

Estrategias que busquem aumentar a produtividade de palha pelas culturas devem ser implementadas na regiao dos Cerrados, no sentido de consolidar o plantio direto. Objetivou-se avaliar a influencia das epocas de aplicacao e do parcelamento da fertilizacao nitrogenada suplementar a adubacao de semeadura no milho sobre a produtividade de palha de aveia preta, especies espontâneas e a influencia desse parcelamento nos diversos componentes da cultura. Os tratamentos constaram da aplicacao de 70kg/ha de nitrogenio, como dose suplementar a adubacao de semeadura do milho, em epocas distintas: na semeadura da aveia-preta; oito dias antes da semeadura do milho; em cobertura, quando as plantas tinham quatro a cinco folhas; em cobertura, quando as plantas tinham sete a oito folhas. Na semeadura, aplicaram-se 42kg/ha de N em todas as parcelas. A adubacao nitrogenada aplicada na semeadura da aveia nao resultou em aumento da produtividade de palha, na entressafra. Houve aumento da produtividade de palha pelo milho quando se aplicou o nitrogenio suplementar a semeadura, assim como a aplicacao mais proxima da semeadura proporcionou aumento da produtividade em relacao a aplicacao do fertilizante na semeadura da aveia.