Estabelecimento de pastagens cultivadas, em area de chapada, na microrregiao de Valenca do Piaui.

Com base nas observacoes efetuadas, podem ser enumerados varios pontos importantes quando do estabelecimento de pastagem cultivada: 1) Controle da vegetacao arbustiva nao desejavel atraves do desmatamento com grade pesada, a uma profundidade adequada. Apos o desmatamento, uma ou duas gradagens com grade hidraulica sao necessarias para diminuir a presenca das invasoras herbaceas que pode, tambem prejudicar o estabelecimento das forrageiras. 2) Face a baixa fertilidade do solo deve ser feitas uma adubacao com fosforo e potassio para permitir o melhor estabelecimento da pastagem plantada. Aconselha-se que a distribuicao dos adubos sejam feitas em linhas, de modo a aumentar o seu aproveitamento pelas plantas e diminuir a fixacao pelo solo. 3)Alem destes cuidados, ainda ha que se considerar a quantidade e distribuicao das chuvas como fator decisivo quando da implantacao de uma pastagem.bitstream/item/95759/1/CT110001.pd

Producao e valor nutritivo de capim-elefante anao sob pastejo.

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Photospheric and chromospheric magnetic activity of seismic solar analogs. Observational inputs on the solar/stellar connection from Kepler and Hermes

We identify a set of 18 solar analogs among the seismic sample of solar-like stars observed by the Kepler satellite rotating between 10 and 40 days. This set is constructed using the asteroseismic stellar properties derived using either the global oscillation properties or the individual acoustic frequencies. We measure the magnetic activity properties of these stars using observations collected by the photometric Kepler satellite and by the ground-based, high-resolution Hermes spectrograph mounted on the Mercator telescope. The photospheric (Sph) and chromospheric (S index) magnetic activity levels of these seismic solar analogs are estimated and compared in relation to the solar activity. We show that the activity of the Sun is comparable to the activity of the seismic solar analogs, within the maximum-to-minimum temporal variations of the 11-year solar activity cycle 23. In agreement with previous studies, the youngest stars and fastest rotators in our sample are actually the most active. The activity of stars older than the Sun seems to not evolve much with age. Furthermore, the comparison of the photospheric, Sph, with the well-established chromospheric, S index, indicates that the Sph index can be used to provide a suitable magnetic activity proxy which can be easily estimated for a large number of stars from space photometric observations.Comment: Accepted for publication in A&

Origem do adensamento em solos do tabuleiro sertanejo do estado de Pernambuco: pedogenetica e/ou deposicional.

O presente trabalho foi desenvolvido para identificar e caracterizar horizontes adensados em podzólico amarelo e solonetz solodizado no semi-árido pernambucano, visando testar a hipótese de que estes apresentam descontinuidade textural

MATHEMATICAL MODELING OF THE DRYING CURVES OF FOXTAIL MILLET SEEDS IN SPOUTED BED

In order to provide a contribution to future studies of foxtail millet (Setaria italica), the drying kinetics of the seeds was investigated at three different temperatures: 44, 65 and 86°C. The seeds of S. italica with a moisture equal to 30% in dry basis were dried in a conical-cylindrical spouted bed during an interval of 132 min. Some empirical mathematical models were selected to describe the experimental drying kinetics data (Lewis, Henderson and Pabis, Page, Diffusion approach, Midilli and Wang and Singh) and the best models were chosen according to the statistical tests results (coefficient of determination, mean relative percent deviation, mean square root error and residue distribution), using the software Statistica® 7.0 and applying the Quasi-Newton method. Only the decreasing rate period was observed in the drying kinetic curves, indicating that the removal of moisture content was preferably by the diffusion mechanism, which is a characteristic behavior of fibrous products, like the agricultural products. The models of Diffusion Aproach, Page and Midilli were the most suitable to describe the experimental drying curves