Effects of Cattle Slurry, Their Solid and Liquid Fractions and Mineral N Fertilizers on Italian Ryegrass and Maize Forage Yield

Solid-liquid slurry separation techniques expand possibilities to improve slurry use efficiency and to reduce its negative environmental impact. These possibilities arise from the different behaviour of the two fractions concerning the release of nutrients, namely nitrogen (N), due to different C:N ratios (≈30 for the solid fraction and ≈7 for the liquid fraction). The aim of this work was to evaluate the effect of cattle-slurry and their solid and liquid fractions applied at sowing time of Italian ryegrass (Lolium multiflorum cv. Andrea) and forage maize on crop dry matter (DM) yield. In the NW region of Portugal these two crops are the bases of an intensive double forage cropping system with silage maize grown from May to October and Italian ryegrass during the winter season

Peletização de sementes de arroz.

O objetivo deste estudo foi verificar a viabilidade da peletização de sementes de arroz, sem prejuízo do poder germinativo e vigor durante o armazenamento e proporcionar adição de zinco às sementes.bitstream/CNPAF/23580/1/comt_111.pd

Probabilistic cellular automata with conserved quantities

We demonstrate that the concept of a conservation law can be naturally extended from deterministic to probabilistic cellular automata (PCA) rules. The local function for conservative PCA must satisfy conditions analogous to conservation conditions for deterministic cellular automata. Conservation condition for PCA can also be written in the form of a current conservation law. For deterministic nearest-neighbour CA the current can be computed exactly. Local structure approximation can partially predict the equilibrium current for non-deterministic cases. For linear segments of the fundamental diagram it actually produces exact results.Comment: 17 pages, 2 figure

Qualidade fisiológica de sementes de feijoeiro comum produzidas em várzeas tropicais com subirrigação.

O objetivo do presente trabalho foi determinar a viabilidade da produção de sementes de feijoeiro comum em várzeas tropicais, com altas temperaturas durante o ciclo da cultura, utilizando-se a subirrigação e comparar sua qualidade com a semente produzida na Embrapa Arroz e Feijão, no inverno, sob pivô central.bitstream/CNPAF/23530/1/bolpesq_14.pd

Effect of dairy effluents pre-treatment on N2O emissions and N-organic degradation after soil application

Nitrous oxide (N2O) is a potent greenhouse gas that plays a key role in climatic forcing contributing to the greenhouse effect by about 4 %, and also contributes to stratospheric ozone depletion. Cattle slurries are commonly applied to agricultural soils, inducing an increase of soil nitrous oxide emissions. Therefore, many procedures were developed for slurry pre-treatment in order to improve soil slurry application and reduce nitrogen losses, namely N2O emissions. The aim of this work was to compare N2O emissions and the kinetic of N organic degradation from treated and untreated cattle-slurry after its incorporation in agricultural soils

Separação de sólidos e nutrientes com PAM e bentonite em chorumes bovinos

A separação de sólidos do chorume e a aplicação de agentes floculantes à fracção líquida obtida constituem processos de tratamento deste efluente pecuário que permitem a obtenção de materiais com características distintas que ampliam as opções de utilização e de gestão do chorume. A redução do teor de sólidos e nutrientes na fracção sobrenadante apresenta vantagens em termos de odores, armazenamento, tratamento, aplicação aos solos e irrigação. Este trabalho teve como objectivo avaliar a utilização dos agentes floculantes poliacrilamida (PAM) e bentonite na remoção de sólidos e nutrientes da fracção líquida do chorume de explorações de bovinicultura leiteira. O trabalho experimental decorreu em Vila do Conde durante 2004, numa exploração de bovinicultura leiteira intensiva. O chorume bruto foi sujeito a separação mecânica de sólidos. Posteriormente a fracção líquida obtida foi bombeada para recipientes, e definiram-se 3 tratamentos com 2 repetições: controlo, adição de 200 mg L -1 de PAM e adição de 2 g L -1 de bentonite. Após a aplicação dos floculantes foram recolhidas amostras às fracções sobrenadante e sedimentada nos tempos 0, 2, 4, 20 e 30 horas. Essas amostras foram analisadas relativamente à concentração de N Kjeldahl, P e K totais, N-NH4 + , P solúvel em água, C orgânico solúvel em água, valor de pH e %MS. A separação mecânica do chorume bruto conduziu a uma eficiência de remoção pela fracção sólida obtida de 22, 25, 44 e 21%, respectivamente, dos teores de N Kjeldahl, P total, P solúvel em água e MS. Quanto à capacidade de remoção dos floculantes, a aplicação de PAM conduziu à eficiência de remoção da fracção sobrenadante de 46, 40, 65, 57 e 40%, respectivamente para o N Kjeldahl, P e K totais, P solúvel em água e MS; e a aplicação de bentonite a remoções de 19, 21, 11, 16 e 12%

Temperature oscillations of magnetization observed in nanofluid ferromagnetic graphite

We report on unusual magnetic properties observed in the nanofluid room-temperature ferromagnetic graphite (with an average particle size of l=10nm). More precisely, the measured magnetization exhibits a low-temperature anomaly (attributed to manifestation of finite size effects below the quantum temperature) as well as pronounced temperature oscillations above T=50K (attributed to manifestation of the hard-sphere type pair correlations between ferromagnetic particles in the nanofluid)

Fracturing highly disordered materials

We investigate the role of disorder on the fracturing process of heterogeneous materials by means of a two-dimensional fuse network model. Our results in the extreme disorder limit reveal that the backbone of the fracture at collapse, namely the subset of the largest fracture that effectively halts the global current, has a fractal dimension of $1.22 \pm 0.01$. This exponent value is compatible with the universality class of several other physical models, including optimal paths under strong disorder, disordered polymers, watersheds and optimal path cracks on uncorrelated substrates, hulls of explosive percolation clusters, and strands of invasion percolation fronts. Moreover, we find that the fractal dimension of the largest fracture under extreme disorder, $d_f=1.86 \pm 0.01$, is outside the statistical error bar of standard percolation. This discrepancy is due to the appearance of trapped regions or cavities of all sizes that remain intact till the entire collapse of the fuse network, but are always accessible in the case of standard percolation. Finally, we quantify the role of disorder on the structure of the largest cluster, as well as on the backbone of the fracture, in terms of a distinctive transition from weak to strong disorder characterized by a new crossover exponent.Comment: 5 pages, 4 figure