954 resultados para Soil physical attributes


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Environmental factors are important in agriculture and need to be considered for getting good degree of development and reasonable efficiency, by reducing their operating costs. To this end, land use shall be appropriated to the conditions offered by the physical elements of the landscape. By facing such questions, this paper aims is to present of mapping the ability of land use of the hydrographic basins Cavalheiro Stream basin (in the city of Analândia - São Paulo State - Brazil) which presents serious erosion problems. Besides it aims to assess if the current land use in this area is consistent with the identified land use ability. For this we have made a cartographic document that spatializes the various classes of usability and its main restrictions. The correlative analysis between that document and land use data showed that Cavalheiro Stream's current use is predominantly inappropriate with the usability of land, which was identified from the physical attributes of the studied area, except for a few sites that are used for forestry and pasture placed in Western, Eastern and Central-South.

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Aiming to evaluate the effect of cover plants over soil chemical attributes in the region of Balsas - Maranhão, samples of Oxisol under plant cover of millet [Pennisetum americanum (L.) Leeke], brachiaria (Brachiaria ruziziensis) and native Cerrado (mid-sized), were collected in three depths (0-0.10; 0.10-0.20 and 0.20-0.40 m). Plant cover of millet and brachiaria promoted an increase in soil pH and reductions in amounts of Al3+ and in saturation by Al3+, in relation to the area with native Cerrado. Major amounts of residue were verified on soil surface under native cerrado, due to greater input of plant residue and lower decomposition rate. Amounts of nutrients and levels of organic matter were higher in areas under millet and brachiaria cover, mainly in 0-0.10 e 0.10-0.20 m. depths. Brachiaria and millet cover plants were similar in relation to alterations promoted in chemical attributes of soil.

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The inadequate and indiscriminate disposal of sugarcane vinasse in soils and water bodies has received much attention since decades ago, due to environmental problems associated to this practice. Vinasse is the final by-product of the biomass distillation, mainly for the production of ethanol, from sugar crops (beet and sugarcane), starch crops (corn, wheat, rice, and cassava), or cellulosic material (harvesting crop residues, sugarcane bagasse, and wood). Because of the large quantities of vinasse produced, alternative treatments and uses have been developed, such as recycling of vinasse in fermentation, fertirrigation, concentration by evaporation, and yeast and energy production. This review was aimed at examining the available data on the subject as a contribution to update the information on sugarcane vinasse, from its characteristics and chemical composition to alternatives uses in Brazil: fertirrigation, concentration by evaporation, energy production; the effects on soil physical, chemical and biological properties; its influence on seed germination, its use as biostimulant and environmental contaminant. The low pH, electric conductivity, and chemical elements present in sugarcane vinasse may cause changes in the chemical and physical-chemical properties of soils, rivers, and lakes with frequent discharges over a long period of time, and also have adverse effects on agricultural soils and biota in general. Thus, new studies and green methods need to be developed aiming at sugarcane vinasse recycling and disposal. © 2013 Elsevier Ltd. All rights reserved.

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The objective of this work was to evaluate the efficiency of superficial applicationof limestone and slag, and their effects on soil chemical attributes and on yield and mineral nutrition of soybean, maize, and Congo signal grass (Urochloa ruziziensis). The experiment was carried out in a Rhodic Hapludox under no tillage system. The treatments consisted of the use of limestone or slag (silicates of calcium and magnesium) to correct soilacidity, and of a control treatment without the use of soil correctives. Rates were calculated in order to raise soil base saturation up to 70%. Soybean was sown in November 2006and maize in December 2007. Congo signal grass was sown right after the harvests of soybean and maize, and it was cropped during the offseasons. Soil chemical attributes were evaluated at 6, 12, and 18 months after the application of the corrective materials. Slag isan efficient source for soil acidity correction, being able to raise the exchangeable base levels in the soil profile faster than lime. Both limestone and slag increase dry matter yield of Congo signal grass, and grain yield of soybean and maize. Slag is more effective in improving maize grain yield.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

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Pós-graduação em Agronomia (Agricultura) - FCA

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Agronomia (Ciência do Solo) - FCAV

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)