Forrageiras para corte e pastejo.

A alimentação é um dos itens que mais oneram o custo de produção animal, seja de leite ou de carne. Dessa maneira deve-se ter em mente que os recursos forrageiros disponíveis na fazenda devem permitir a obtenção de elevadas produções de leite e/ou carne por área por um longo período de tempo e de forma econômica, principal meta de quem lida com a atividade agropecuária. Com esse intuito, esta publicação procura englobar informações tecnológicas advindas de resultados de pesquisa, descrevendo características produtivas de diferentes forrageiras tropicais e temperadas e suas diferentes formas de uso, bem como respostas em relação ao manejo, à adubação e à irrigação, apresentando, ainda, resultados quantitativos e qualitativos e recomendações para melhor utilização dessas plantas forrageiras, presentes na maioria dos sistemas de produção animal.bitstream/item/81889/1/Forrageiras-para-corte.pd

A pesquisa em producao de leite a pasto na Embrapa Gado de Leite - 1980 a 1999.

Esta publicação apresenta resultados quantitativos e qualitativos dessas forrageiras, bem como a evolução da pesquisa em produção de leite a pasto na Embrapa Gado de Leite no per(odo compreendido entre 1980 e 1999. Essas forrageiras têm possibilitado, durante a época chuvosa, taxas de lotação de até cinco vacas/ha, além de produções de leite ao redor de 12 kg/vaca/dia, sem o uso de suplementação concentrada. As informações contidas neste documento podem ser úteis para técnicos e produtores que lidam com a atividade leiteira, especialmente aqueles que procuram tecnologias de intensificação da produção de leite à base de pastagens.bitstream/item/81888/1/A-pesquisa-em-producao-de-leite-a-pasto.pd

Viabilidade de implantacao de aveia em pastagens estabelecidas de capim-elefante.

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Entanglement negativity in a two dimensional harmonic lattice: Area law and corner contributions

We study the logarithmic negativity and the moments of the partial transpose in the ground state of a two dimensional massless harmonic square lattice with nearest neighbour interactions for various configurations of adjacent domains. At leading order for large domains, the logarithmic negativity and the logarithm of the ratio between the generic moment of the partial transpose and the moment of the reduced density matrix at the same order satisfy an area law in terms of the length of the curve shared by the adjacent regions. We give numerical evidence that the coefficient of the area law term in these quantities is related to the coefficient of the area law term in the R\ue9nyi entropies. Whenever the curve shared by the adjacent domains contains vertices, a subleading logarithmic term occurs in these quantities and the numerical values of the corner function for some pairs of angles are obtained. In the special case of vertices corresponding to explementary angles, we provide numerical evidence that the corner function of the logarithmic negativity is given by the corner function of the R\ue9nyi entropy of order 1/2

Universal scaling of the logarithmic negativity in massive quantum field theory

We consider the logarithmic negativity, a measure of bipartite entanglement, in a general unitary 1 + 1-dimensional massive quantum field theory, not necessarily integrable. We compute the negativity between a finite region of length r and an adjacent semi-infinite region, and that between two semi-infinite regions separated by a distance r. We show that the former saturates to a finite value, and that the latter tends to zero, as r -> ∞. We show that in both cases, the leading corrections are exponential decays in r (described by modified Bessel functions) that are solely controlled by the mass spectrum of the model, independently of its scattering matrix. This implies that, like the entanglement entropy (EE), the logarithmic negativity displays a very high level of universality, allowing one to extract information about the mass spectrum. Further, a study of sub-leading terms shows that, unlike the EE, a large-r analysis of the negativity allows for the detection of bound states

Desempenho de animais em aveia sob pastejo continuo.

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Characterization of cover crops by NMR spectroscopy: impacts on soil carbon, nitrogen and phosphorus under tilage regimes.

The objective of this study was to investigate the chemical composition of cover crops by solid-state CPMAS 13C NMR spectroscopy and its effects on carbon, nitrogen and phosphorus in a Typic Acrustox. Cover crops (Crotalaria juncea, Canavalia brasiliensis, Cajanus cajan, Mucuna pruriens and Raphanus sativus) and natural fallow were studied in rotation with maize under conventional and no-tillage regimes. Tissues of Crotalaria juncea, Canavalia brasiliensis, Mucuna pruriens and Raphanus sativus were analyzed using CPMAS 13C NMR spectroscopy. Soil samples were collected at the end of the growing season of the cover crops (September 2002) and during the grain filling period in corn from 0-5 and 5-10 cm layers. Cajanus cajan presented the lowest content of polysaccharides and along with Mucuna pruriens presented the highest percentage of aromatic carbon compounds, reflecting the slow decomposition of highly lignified material. Carbon stocks were higher in the superficial soil layer and under no-tillage due to the accumulation and slower decomposition of plant tissues under these conditions. Increases in the C/N ratio of the soil with Mucuna pruriens and the C/P ratio with Cajanus cajan in the dry season were also related to slower rates of decomposition, caused by the large concentration of aromatic compounds in the tissues of these species. The higher C/P ratios found at 0-5 cm layer are due to higher values of P (Mehlich-1) at 5-10 cm (25 mg kg-1) layer and the higher concentration of carbon in the superficial soil layer as a result of the accumulation of plant residues