1000 resultados para Seqüência de cultivos


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Pós-graduação em Ciências Biológicas (Zoologia) - IBRC

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Pós-graduação em Agronomia (Agricultura) - FCA

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Planning is an essential instrument for the agricultural occupation of the lands, because it supports the activities of food production and raw materials. It must be driven by techniques that provide the sustainability of these activities, so that also ensures the environmental balance of agroecosystems. Lands misuse can be considered as one of the causes of frustration of agricultural activities. Thus, the occurrence of discrepancies between the effective use (real use) of the land and its agricultural aptitude can compete, in many cases, to the decrease of productivity, as well as for soil degradation. In this way, this research intends to study the relationship between the temporary cultivations, halfperennial cultures, perennial and its developmental environment, determining the edaphoclimatic characteristics of landscapes. From then on, a letter shall be subject to the use and occupation of the soil for agriculture in the municipality of Cristais Paulista-SP, aiming to describe the spatial organization of land use and vegetation cover, and emphasizing management and conservative practices. For that, climatic factors were characterized, fundamentally humidity, temperature and luminosity; edaphics, including parental material, chemical and physical properties, fertility, soil temperature and climatic zoning; biotic, referring to the suitability of different cultures or to be implanted; physical, such as geomorphology, slope, geology, hypsometry and hydrology; socioeconomic, in particular production and marketing seasons; and the way they all, together, affect the adaptation, distribution and production of crops. Using this information, the zoning of the area of study was done based on the 21 nominated groups obtained, in addition to recommendations and suggestions for handling each type of cultivation... (Complete abstract click electronic access below)

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The new market, focused on sustainability and other environmental concerns, refers to innovations that seek alternative forms of production. In pulp and paper bleaching alternative reagents are studied, for example, hydrogen peroxide, in partial substitution of chlorine dioxide in order to reduce the formation of organochlorines. In this context, this study examined the burden of hydrogen peroxide (H2O2) on alkaline extraction stage (stage Ep) required for the bleaching of pulp with eucalyptus kraft pulp, pre-oxygen delignified to obtain equivalent brightness at 90 ± 0.5% ISO, as well as its effect on quality of pulp produced. The pulp was bleached by the sequence D(Ep)DP, with the application of factor kappa of 0.14 and varying the concentration of hydrogen peroxide in Ep stage three, five, seven and nine kilograms of reagent per ton of pulp absolutely drought. The final P stage was optimized with the use of six, nine and twelve pounds of hydrogen peroxide per ton of absolutely dry pulp to achieve the required brightness. The quality of the pulp produced was analyzed based on the kappa number, the brightness and the viscosity. The methods were performed according to standards set by the standard TAPPI (Technical Association of the Pulp and Paper Industry). The best result was obtained using the following D0Ep(7)D1P(6), which showed a viscosity of 19.9 cP, 89.6% ISO brightness, consumption of 94.9 kg / t of reagents and reagent costs of US$ 28.15, because it showed better pulp quality for a lower cost compared to the others. It was found that the greater the amount of hydrogen peroxide in alkaline extraction, the lower the kappa number and increased the amount of residual hydrogen peroxide. The higher the charge of hydrogen peroxide in Ep stage, the lower the need for hydrogen peroxide in the final P stage, reducing the cost of bleaching

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

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[ES] El objetivo principal de esta tesis ha sido presentar soluciones a los problemas de conservación que afectan a la especie Cymodocea nodosa y su ecosistema en Canarias, llevando a cabo estrategias de conservación ex situ que incluyen el desarrollo de una técnica de propagación con la que obtener plántulas germinadas a partir de semillas, su aclimatación y trasplante al mar. Una vez desarrollada la técnica de propagación in vitro, nos planteamos abordar estrategias para optimizar el procedimiento establecido, interviniendo sobre la conservación de las semillas in vitro y sobre la mejora, previo al trasplante, del estatus nutritivo y del crecimiento de las plántulas. Con la experiencia adquirida se han establecido las bases del cultivo in vitro a partir de tejido embrionario, permitiendo el mantenimiento de cultivos celulares en condiciones asépticas. El protocolo desarrollado supone una herramienta nueva y fundamental para el futuro del cultivo in vitro de esta especie, ya que permite ensayar nuevas técnicas y protocolos de regeneración para poder obtener, en un futuro, embriones somáticos que se desarrollen hasta plantas completas aplicando la técnica de germinación y propagación desarrollada, y proveer, así, de material vegetal para llevar a cabo programas de restauración y trasplante sin recurrir a las praderas naturales.

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Valoración de la cantidad y calidad de la carragena de cultivares de Panamá

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Departamento de Biología (Botánica), Facultad de Ciencias, Universidad Autónoma de Madrid

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[ES] Este artículo analiza 16 cárcavas efímeras en campos de cultivo en el norte de Tenerife (Las Llanadas) tras lluvias intensas caídas en noviembre de 2009. Se estudiaron “gullies” en parcelas con diferentes tipos de cultivo: maíz, cereal, papas y sin cultivo. Se observó que las cárcavas presentan diferencias morfológicas y de tamaño en relación con el tipo de cultivo sobre el que se han generado, por lo que las parcelas con maíz son más vulnerables a los procesos de erosión, mientras que la de cereal son las menos. Sin embargo, también se aprecia que la desaparición de elementos tradicionales en los campos de cultivo (zanjas, muros de piedras, etc.) son los máximos responsables de la formación y la mayor incidencia de las cárcavas por lluvias torrenciales. Por tanto, es necesario que los agricultores vuelvan a recuperar, y así se ha constatado, los elementos tradicionales que progresivamente han ido desapareciendo de los campos de cultivo. [EN] In this work 16 ephemeral gullies of the north of Tenerife (Las Llanadas) are studied. these gullies are located in agricultural land (corn, cereal, potatoes and without cultivations) and they were formed for torrential rains. The gullies possesses different size and morphologies according to cultivations type. However, the elimination of traditional elements in the agricultural fields, they have provoked bigger effect of the torrential rains.