Ferrugem da soja: prevenção através de cultivares resistentes.

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Bilan et perspectives de la Recherche en Agriculture Bio-dynamique

L’Agriculture Biodynamique (BD) a été l’objet de nombreux efforts de recherches durant les dernières décennies, bien qu’une partie de la communauté scientifique regarde les méthodes biodynamiques avec scepticisme et les considère comme dogmatiques. Néanmoins, comme cela est montré dans cet article de synthèse, une part non négligeable des résultats présentés dans des revues scientifiques à comité de lecture et issus d’expérimentations contrôlées de plein champ, ou d’étude de cas, montrent des effets des préparations biodynamiques sur le rendement, la qualité du sol et la biodiversité. De plus, les préparations biodynamiques ont un impact environnemental positif en termes d’utilisation et d’efficacité énergétique. Cependant, le mode d’action mécanique des préparations biodynamique est toujours en cours d’investigation en sciences naturelles. Par ailleurs, les méthodes d’évaluations de la qualité basées sur des approches globales (holistiques) sont de plus en plus étudiées et reconnues. L’agriculture BD s’efforce également, comme cela est montré dans plusieurs publications, d’influencer positivement le paysage culturel. La synthèse des données montre le besoin de poursuivre les recherches dans le domaine de la qualité des aliments, de la sécurité alimentaire, des performances environnementales (par ex. l’empreinte écologique), et sur l’influences des pratiques BD sur les animaux d’élevage

Ocorrência de fungos em sementes de sorgo, milho, soja e trigo.

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Synchronisation of egg hatching of brown hairstreak (Thecla betulae) and budburst of blackthorn (Prunus spinosa) in a warmer future

Synchronisation of the phenology of insect herbivores and their larval food plant is essential for the herbivores’ fitness. The monophagous brown hairstreak (Thecla betulae) lays its eggs during summer, hibernates as an egg, and hatches in April or May in the Netherlands. Its main larval food plant blackthorn (Prunus spinosa) flowers in early spring, just before the leaves appear. As soon as the Blackthorn opens its buds, and this varies with spring temperatures, food becomes available for the brown hairstreak. However, the suitability of the leaves as food for the young caterpillars is expected to decrease rapidly. Therefore, the timing of egg hatch is an important factor for larval growth. This study evaluates food availability for brown hairstreak at different temperatures. Egg hatch and budburst were monitored from 2004 to 2008 at different sites in the Netherlands. Results showed ample food availability at all monitored temperatures and sites but the degree of synchrony varied strongly with spring temperatures. To further study the effect of temperature on synchronisation, an experiment using normal temperatures of a reference year (T) and temperatures of T + 5°C was carried out in climate chambers. At T + 5°C, both budburst and egg hatch took place about 20 days earlier and thus, on average, elevated temperature did not affect synchrony. However, the total period of budburst was 11 days longer, whereas the period of egg hatching was 3 days shorter. The implications for larval growth by the brown hairstreak under a warmer climate are considered.

Resonant wave interactions in the equatorial waveguide

Weakly nonlinear interactions among equatorial waves have been explored in this paper using the adiabatic version of the equatorial beta-plane primitive equations in isobaric coordinates. Assuming rigid lid vertical boundary conditions, the conditions imposed at the surface and at the top of the troposphere were expanded in a Taylor series around two isobaric surfaces in an approach similar to that used in the theory of surface-gravity waves in deep water and capillary-gravity waves. By adopting the asymptotic method of multiple time scales, the equatorial Rossby, mixed Rossby-gravity, inertio-gravity, and Kelvin waves, as well as their vertical structures, were obtained as leading-order solutions. These waves were shown to interact resonantly in a triad configuration at the O(epsilon) approximation. The resonant triads whose wave components satisfy a resonance condition for their vertical structures were found to have the most significant interactions, although this condition is not excluding, unlike the resonant conditions for the zonal wavenumbers and meridional modes. Thus, the analysis has focused on such resonant triads. In general, it was found that for these resonant triads satisfying the resonance condition in the vertical direction, the wave with the highest absolute frequency always acts as an energy source (or sink) for the remaining triad components, as usually occurs in several other physical problems in fluid dynamics. In addition, the zonally symmetric geostrophic modes act as catalyst modes for the energy exchanges between two dispersive waves in a resonant triad. The integration of the reduced asymptotic equations for a single resonant triad shows that, for the initial mode amplitudes characterizing realistic magnitudes of atmospheric flow perturbations, the modes in general exchange energy on low-frequency (intraseasonal and/or even longer) time scales, with the interaction period being dependent upon the initial mode amplitudes. Potential future applications of the present theory to the real atmosphere with the inclusion of diabatic forcing, dissipation, and a more realistic background state are also discussed.FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo)[02/09683-9]PROSUR/IRIMoore FoundationNS

Herbage Intake, Methane Emissions and Animal Performance of Steers Grazing Dwarf Elephant Grass with or without Access to \u3cem\u3eArachis pintoi\u3c/em\u3e Pastures

The inclusion of legumes in diets based on grass has nutritional benefits due to ingestive and digestive interactions (Niderkorn and Baumont 2009). Moreover, it is speculated that tropical legumes can contribute to reducing the emission of greenhouse gases (GHG) compared to diets exclusively composed of grasses (Archimède et al. 2011). However, under grazing conditions, these advantages are not always possible to obtain. This occurs when the spatial distribution of sward grasses impose limitations on access to legumes by grazing animals (Solomon et al. 2011). This can be the case, for example, when legumes are overlapped by the leaves of a tufted tall grass, as dwarf elephant grass (Crestani et al. 2013). Considering that management strategies for increasing legumes in the diet of grazing animals should be better studied and data on enteric methane emitted by ruminants eating tropical forages are scarce, the aim of this work was to evaluate the effect of access to an exclusive area of peanuts (Arachis pintoi cv. Amarillo) for cattle grazing dwarf elephant grass (Pennisetum purpureum cv. BRS Kurumi) on herbage intake, animal performance and enteric methane emission

Economic analysis of the use of rice husk ash in the production of clay ceramics

Abstract Studies have proven that the use of waste in the production of clay ceramics is common for achieving the technical performance that is necessary for the application of these by-products. However, it is essential to analyze the feasibility of using these materials in terms of productivity and economic gains, in line with sustainability. The objective of this study is to determine the cost-benefit ratio of using rice husk ash in the production of clay ceramics. The methodological process consisted of a comparative analysis on an industrial scale between the formulation with up to 15% by volume of rice husk ash and the standard formulation previously used by the company. The economic aspects included the costs/consumption of raw materials, transport, and energy. The productivity throughout the process and technical characteristics of the final product were also evaluated. The costs of raw materials showed a financial gain of 7.0%, whereas the productivity analysis revealed that the greatest economic gain was in energy consumption during drying (13%)

Avaliação de cultivares de sorgo granífero na safra de 2004/2005 do ensaio Sul-Rio-Grandense.

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