Produtividade e qualidade de cana-de-açúcar cultivada em solo tratado com lodo de esgoto, vinhaça e adubos minerais

O uso agrícola de resíduos orgânicos, de origem agrícola, urbana ou industrial, é uma interessante alternativa de disposição, permitindo a reciclagem de nutrientes (NPK) nos ecossistemas. Este trabalho avaliou o efeito da aplicação de lodo de esgoto como fonte de N e de vinhaça como fonte de K comparado ao uso de fontes minerais desses nutrientes sobre a produtividade e variáveis agroindustriais da cana-de-açúcar, por dois anos consecutivos (cana-planta e cana-soca). O experimento foi conduzido em Latossolo Vermelho-Amarelo distrófico típico, em Pontal - SP, e a variedade de cana-de-açúcar avaliada foi a SP 81-3250. Utilizou-se de esquema fatorial 3x2x2+1, ou seja, três tipos de resíduos (lodo de esgoto + KCl; vinhaça + uréia, e lodo de esgoto + vinhaça); dois modos de aplicação (na linha de plantio ou em área total); duas doses (100 e 200% do N e K necessários à cultura) e um tratamento adicional com adubação mineral, sendo os tratamentos distribuídos na área em blocos ao acaso, com três repetições. Foram avaliadas a produtividade e as variáveis agroindustriais (°brix, pol no caldo, fibra, pureza, pol na cana, AR e ATR). As produtividades de colmo e de açúcar para cana-planta foram mantidas quando N e K foram fornecidos pelo lodo de esgoto e vinhaça, respectivamente. A cana-soca apresentou maior produtividade de colmo e de açúcar quando foram utilizados os resíduos separadamente, complementados com fontes minerais. Quanto ao modo de aplicação, não foram observadas diferenças significativas para as variáveis analisadas.

Orchid in vitro growth as affected by nitrogen levels in the culture medium

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Variação espacial e temporal da produtividade primária pelo fitoplâncton na represa de Jurumirim (Rio Paranapanema, SP)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Study on the use of oxidant scrubbers for elimination of interferences due to nitrogen dioxide in analysis of atmospheric dimethylsulfide

Neste trabalho foi avaliado o desempenho de filtros para dióxido de nitrogênio, buscando evitar perdas durante a amostragem de sulfetos orgânicos, provocadas por oxidantes atmosféricos. Diferentes compostos e misturas foram usadas para recobrir superfícies sólidas empregadas na preparação destes filtros. Um sistema automatizado de análise em fluxo foi utilizado para comparar a eficiência de retenção de dióxido de nitrogênio pelos filtros. Entre os materiais testados na preparação dos filtros, as melhores escolhas foram papel ou lã de vidro impregnados com a mistura de sulfato de ferro (II), ácido sulfúrico e ácido pirogalico e ainda os filtros feitos de papel impregnados com trietanolamina. Os resultados obtidos em laboratório com mistura de gás padrão de dimetilsulfeto e experimentos em campo confirmaram a qualidade dos filtros e indicaram que eles podem ser utilizados para evitar a oxidação de sulfetos orgânicos durante a sua amostragem.

Effects of irrigation and nitrogen levels on qualitative and nutritional aspects of fig-trees (Ficus carica L.)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sugarcane grown in an oxisol amended with sewage sludge and vinasse: nitrogen contents in soil and plant

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Nitrogen assimilation in Citrus based on CitEST data mining

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Morphogenetic and tillering dynamics in Tanzania grass fertilized and non-fertilized with nitrogen according to season

The objectives of this study were to evaluate morphogenetic characteristics and tillering dynamics in Tanzania grass fertilized and non-fertilized with nitrogen, under intermittent grazing, in the spring and the summer. The main plots were composed of four nitrogen rates (0, 100, 200 and 300 kg/ha) and the subplots were growth seasons: spring (October, November and December) and summer (January, February and March). The experimental design was of randomized block with plots subdivided by time (seasons of the year) and four replications. Urea was used as nitrogen supply and was divided into two applications: one in the spring and another in the summer. The experimental units fertilized with N rates of 200 and 300 kg/ha showed six cycles of pasture, with an average of 27 days of pasture interval, while the treatments with no fertilization and 100 kg/ha of N showed only four and five cycles of pasture, respectively. Leaf elongation rate (LER) and the leaf appearance rate (LAR) increased linearly with increasing of N rates. The greatest population density occurred in summer with the higher nitrogen rates. The treatment without N fertilization showed the lowest growth of tiller population, while the other treatments exhibited growth rates above 50% when compared with non-fertilized samples. Nitrogen rates significantly affect the leaf appearance rate and the leaf elongation rate, as well as the number of live leaves in plants of Tanzania grass in both spring and summer.

Genetic and physiological alterations occurring in a yeast population continuously propagated at increasing temperatures with cell recycling

This work investigated the effects of increasing temperature from 30 degrees C to 47 degrees C on the physiological and genetic characteristics of Saccharomyces cerevisiae strain 63M after continuous fermentation with cell recycling in a system of five reactors in series. Steady state was attained at 30 degrees C, and then the temperature of the system was raised so it ranged from 35 degrees C in the last reactor to 43 degrees C in the first reactor or feeding reactor with a 2 degrees C difference between reactors. After 15 days at steady state, the temperature was raised from 37 degrees C to 45 degrees C for 25 days at steady state, then from 39 degrees C to 47 degrees C for 20 days at steady state. Starter strain 63M was a hybrid strain constructed to have a MAT a/alpha, LYS/lys, URA/ura genotype. This hybrid yeast showed vigorous growth on plates at 40 degrees C, weak growth at 41 degrees C, positive assimilation of melibiose, positive fermentation of galactose, raffinose and sucrose. of 156 isolates obtained from this system at the end of the fermentation process, only 17.3% showed the same characteristics as starter strain 63M. Alterations in mating type reaction and in utilization of raffinose, melibiose, and sucrose were identified. Only 1.9% of the isolates lost the ability to grow at 40 degrees C. Isolates showing requirements for lysine and uracil were also obtained. In addition, cell survival was observed at 39-47 degrees C, but no isolates showing growth above 41 degrees C were obtained.

Mass fractal characteristics of silica sonogels as determined by small-angle x-ray scattering and nitrogen adsorption

A sample series of silica sonogels was prepared using different water-tetraethoxysilane molar ratio (r(w)) in the gelation step of the process in order to obtain aerogels with different bulk densities after the supercritical drying. The samples were analyzed by means of small-angle x-ray-scattering (SAXS) and nitrogen-adsorption techniques. Wet sonogels exhibit mass fractal structure with fractal dimension D increasing from similar to2.1 to similar to2.4 and mass-fractal correlation length xi diminishing from similar to13 nm to similar to2 nm, as r(w) is changed in the nominal range from 66 to 6. The process of obtaining aerogels from sonogels and heat treatment at 500degreesC, in general, increases the mass-fractal dimension D, diminishes the characteristic length xi of the fractal structure, and shortens the fractal range at the micropore side for the formation of a secondary structured particle, apparently evolved from the original wet structure at a high resolution level. The overall mass-fractal dimension D of aerogels was evaluated as similar to2.4 and similar to2.5, as determined from SAXS and from pore-size distribution by nitrogen adsorption, respectively. The fine structure of the secondary particle developed in the obtaining of aerogels could be described as a surface-mass fractal, with the correlated surface and mass-fractal dimensions decreasing from similar to2.4 to similar to2.0 and from similar to2.7 to similar to2.5, respectively, as the aerogel bulk density increases from 0.25 (r(w)=66) up to 0.91 g/cm(3) (r(w)=6).

Small-angle X-ray scattering and nitrogen adsorption study of the nanoporosity elimination in TEOS sonohydrolysis-derived xerogels

Small-angle X-ray scattering (SAXS) and nitrogen adsorption techniques were used to study the temperature and time structural evolution of the nanoporosity in silica xerogels prepared from acid- and ultrasound-catalyzed hydrolysis of tetraetboxysilane (TEOS). Silica xerogels present a structure of nanopores of fully random shape, size, and distribution, which can be described by an exponential correlation function gamma(r) = exp (-r/a), where a is the correlation distance, as predicted by the Debye, Anderson, and Brumberger (DAB) model. The mean pore size was evaluated as about 1.25 nm from SAXS and about 1.9 nm from nitrogen adsorption. The nanopore elimination in TEOS sonohydrolysis-derived silica xerogels is readily accelerated at temperatures around 900 degrees C probably by the action of a viscous flow mechanism. The nanopore elimination process takes place in such a way that the pore volume fraction and the specific surface are reduced while the mean pore size remains constant. (c) 2005 WILEY-VCH Verlag GmbH S Co. KGaA, Weinheim.

Plasma immersion ion implantation of nitrogen into H13 steel under moderate temperatures

Ion implantation of nitrogen into samples of tempered and quenched H13 steel was carried out by plasma immersion technique. A glow discharge plasma of nitrogen species was the ion source and the negative high voltage pulser provided 10-12 kV, 60 mu s duration and 1.0-2.0 kHz frequency, flat voltage pulses. The temperatures of the samples remained between 300 and 450 degrees C, sustained solely by the ion bombardment. In some of the discharges, we used a N-2 + H-2 gas mixture with 1:1 ratio. PIII treatments as long as 3, 6, 9 and up to 12 h were carried out to achieve as thickest treated layer as possible, and we were able to reach over 20 mu m treated layers, as a result of ion implantation and thermal (and possibly radiation enhanced) diffusion. The nitrogen depth profiles were obtained by GDOS (Glow Discharge Optical Spectroscopy) and the exact composition profiles by AES (Auger Electron Spectroscopy). The hardness of the treated surface was increased by more than 250%, reaching 18.8 GPa. No white layer was seen in this case. A hardness profile was obtained which corroborated a deep hardened layer, confirming the high efficacy of the moderate temperature PIII treatment of steels. (c) 2005 Elsevier B.V. All rights reserved.