1000 resultados para Vegetação de cobertura


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

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

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O nitrogênio é o nutriente mais exigido pelo feijoeiro e seu metabolismo pode ser seriamente prejudicado pela deficiência de molibdênio. Conduziu-se este trabalho, com o objetivo de avaliar o efeito da aplicação de molibdênio via semente e nitrogênio em cobertura nas características agronômicas e produtividade do feijoeiro 'BRS Pontal' irrigado, cultivado em Neossolo Quartzarênico, no município de Cassilândia, MS. O delineamento experimental utilizado foi o de blocos casualizados, no esquema fatorial 4x2, com quatro repetições. Os tratamentos foram constituídos pela aplicação ou não de Mo (80 g ha-1) via semente e quatro doses de N (0, 30, 60 e 120 kg ha-1), em cobertura aos 16 dias, após a emergência, na forma de uréia. A aplicação de Mo via semente aumentou o índice relativo de clorofila, o número de vagens por planta, a massa e a produtividade de grãos no feijoeiro, principalmente com o uso de altas doses de N em cobertura. O índice relativo de clorofila, o número de vagens por planta, a massa e a produtividade de grãos do feijoeiro foi aumentada linearmente pela aplicação de até 120 kg ha-1 de N em cobertura. O fornecimento de Mo via tratamento de semente aumentou a eficiência de utilização do N pelo feijoeiro.

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O experimento foi conduzido no período de 27/05/2006 a 02/08/2006 no SIPA (Sistema Integrado de Produção Agroecológica), localizado no município de Seropédica-RJ. Nesse trabalho, objetivou-se avaliar o desempenho da cultura da alface (Lactuca sativa L.) cultivada sob diferentes lâminas de irrigação em um solo sem e com cobertura de palhada da leguminosa gliricídia. Foram conduzidos dois experimentos simultâneos, utilizando o delineamento experimental de blocos ao acaso, em ambos os experimentos, nos quais foram aplicadas 5 lâminas de irrigação, correspondendo a 25, 50, 80, 100, 115 % da evapotranspiração da cultura (ETc), sendo a produção final avaliada por meio da determinação da massa fresca, área foliar e número de folhas. Até o nível de 100% ETc, todas as variáveis analisadas tiveram seus valores aumentados, e para o nível de 115%, houve um decrescimento das mesmas. Na produção de massa fresca total, o sistema de cultivo com utilização de cobertura morta foi superior ao sem cobertura não diferenciando estatisticamente ao nível de 5 % probabilidade pelo teste F somente nas lâminas de 25 e 115% ETc.

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This work was carried out at FCAV-UNESP, Campus of Jaboticabal, Brazil, to study the effects of nitrogen fertilization (0 and 50 kg N/ha/cut), three sucessive periods of growth (December 21st 1987, January 25th 1988 and February 29th 1988)) and three cutting ages (28, 35 and 42 days) on composition in crude protein and in vitro dry matter digestibility of two cultivars of Panicum maximum Jacq. i.e., Coloniao and Tobiata. Plants were harvested in five vertical layers above soil level (0-20, 20-40, 40-60, 60-80 and over 80 cm). The samples were divided in: green leaves, green stems and dry material. Generally, values of in vitro dry matter digestibility and the levels of crude protein of both cultivars were greater in the higher layers of the vegetation, with a decrease, however, for the other layers and more advanced phases of plants development, mainly with no N fertilization.

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The study of the spatial variability of soil attributes under different crop helps the study of changes due the management. This research was carried out to determine spatial variability the particle-size distribution, using of the classic statistic and geostatistics, of a soil cultivated with pasture and native vegetation. Soil samples were collected in the layer 0-0.20m, at the crossing points of a regular grid with 10m-intervals, summing up 64 samples points in each area. In the pasture area the fractions of coarse and total sand presented larger mean values in relation to the native vegetation, and negative correlation with the altitude of the points samples in the two areas. All of the fractions presented moderate to high spatial dependence in the two areas and with the defined still, with exception of the fine sand and the silt in the pasture. Much of this variability occurs as a function of water erosion.

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The microorganisms are essential components in the maintenance of the biological and physicochemical balance of the soil. They exert important function including the degradation of residues of plants and animals and the release of nutrients in the alimentary chain. This work had as objective to compare the microbiota of a soil under bush covering (SMS) and other cropped with vegetables (SHC), suppressive or not it Rhizoctonia solani. Total microbial community DNA was extracted of soils, amplification for PCR of the genes 16S rDNA, inserted into pGEM (R)-T cloning vector and sequencing of the genes of the ribosomal RNA. The analysis of the results demonstrated that this methodology was efficient for evaluation of bacteria in ground. In the bush soil suppressive the microorganisms more found belonged to the phyla of the Acidobacterias, Verrucomicrobia and Actinobacterias and in the soil cultivated with vegetables the biggest frequency was of organisms pertaining to the phyla of the Proteobacterias, Firmicutes and Bacteroidetes.

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The water restriction can damage the performance of crops, especially in the flowering period. Thus, the aim of this research was to evaluate the response of genotypes of wheat submitted to water deficit in the beginning of flowering. The experiment was conducted in greenhouse, in a completely randomized design, in factorial scheme 3 x 2, with five replications. The factors studied were: three wheat cultivars (Coodetec (CD) 105, 108 and 111) and 2 irrigation managements (with and without imposition of water deficit). During the period of water deficit imposition, gravimetric soil moisture and the relative content of water in leaf were evaluated, while at the moment of rehydration the biometric variables were determined. At the end of the crop cycle the components of production were evaluated. Reduction was found in the gravimetric soil moisture, in the relative levels of water and in all biometric variables, in function of the water deficit. The grain production showed difference only among the water regimes, in which the cultivar CD 111 is more efficient in the maintenance of the productive potential in conditions of water deficit, through the quick recovery in the relative content of water in leaves.

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The sugar cane crop has been cultivated in all regions of the Brazil, occupying different soil types. The north region of Mato Grosso has favorable climate conditions for the culture, however, has been achieved low productivity due to the not application of fertilizer and inefficient doses. Being the potassium the mineral element absorbed in large amount by culture. Aimed to with this work to evaluate the effect of growing doses of the nutrient applied in coverage in the second cycle of the variety of sugar cane IAC86-2480. The experimental design was randomized blocks, with four replications. The Potassium doses were: 0; 60; 120; 180 e 240 kg ha(-1) of K(2)O. Was evaluated the degrees Brix, diameter, weigth, height and productivity of stalk. No was significant effects for the variable degrees Brix in response to potassium doses, since to others had response quadratic. The dose of maximum agronomic efficiency was of 150 kg ha(-1) de K(2)O obtaining productivity of 85 t ha(-1) of stalk, representing 25% increase in productivity.

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Occurrence and distribution of 12 natural and anthropic communities were mapped.-from English summary

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This study evaluate the native species naturally regenerating in Eucalyptus saligna stand understory. This stand is located at Itatinga Experimental Station, of the Forest Sciences Department (ESALQ/USP). The experimental area encompasses two sites separated from each other around 250 m, differing 30 m in altitude. These two sites are different mainly in land slope and soil fertility and soil hydric retention capacity. Eight permanent plots of 625 m2 in each site were randomly sampled. The woody species Individuals with height equal or bigger than 1,5 m and the Eucalyptus saligna coppicings were surveyed in each plot. A total of 107 species were Identified and 7 species were common to both sites, distributed into 72 genera and 34 families. Based upon the results It is possible to conclude that the Eucalyptus saligna trees do not preclude the natural regeneration of the native species in the stand understory, however the floristic structure of the community is also influenced by edaphic factors and vicinity of seed sources.

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The aim of this study was to evaluate the influence of different types of rhizomes utilized as seed and the effects of mulch in the culture of Turmeric. This work was conducted in the experimental cultivation area of the Universidade de Ribeirão Preto - UNAERP, in Ribeirao Preto, state of Sao Paulo, Brazil from September/1997 to July/1998. The experiments were arranged in a randomized complete block with a factorial arrangement 2x3, design with 4 replications (32 plants each). The treatments consisted of the use of types of rhizomes utilized to proliferation (head and finger) and types of mulch (absent, grass and leaves/branches). This study investigated proliferation (61, 88 and 124 days after installation), length, shooting and number of leaves of the mother plant besides the number of leaves of the shoot (112, 146 and 233 days after installation), number of finger rhizomes and head rhizomes, fresh and dry biomass of rhizomes and the yield of essential oil (after harvest - July 1998). Obtained results showed a great influence of the type of rhizome used to proliferation. Head rhizomes produced, in weight, about 30% more, when compared to plants from finger rhizomes. Mulching almost duplicated rhizome productivity from 2338 kg.ha -1 of dry rhizomes to 4499 kg.ha -1, when rhizome used to proliferation was finger and from 3046 kg.ha -1 to 5943 kg.ha -1, when using head rhizomes. The yield of essential oil did not show any alteration, independently of the treatments realized.

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The mapping of the land use, vegetation and environmental impacts using remote sensing and geoprocessing allows detection, spatial representation and quantifying all alterations due to the human action in the nature, contributing to the monitoring and planning of those activities that cause damages to the environment. The aim of this research is analyze the transformation ocurred with the land use and vegetation in order to detect environmental impacts during the period from 1962 to 1995, considering a test area in the district of Assistência and surroundings, in the Rio Claro (SP) region. In order to archieve such aim the authors used boolean operations available in the Geographical Information System (GIS) - Idrisi. The maps were obtained through the ordinary (conventional) interpretation of aerial photos, later digitized in the software CAD Overlay and georeferenced in AutoCAD Map. It's observed that operations such as crossing digitized maps of one specific area in two differents dates, using GIS, produce overall results that might point out expansion or retraction's trends of the mapped classes, as well as quantify the intensity of the phenomena.

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The mapping of the land use, vegetation and environmental impacts using remote sensing ana geoprocessmg allow detection, spatial representation and quantification of the alterations caused by the human action on the nature, contributing to the monitoring and planning of those activities that may cause damages to the environment. This study apply methodologies based on digital processing of orbital images for the mapping of the land use, vegetation and anthropic activities that cause impacts in the environment. It was considered a test area in the district of Assistência and surroundings, in Rio Claro (SP) region. The methodology proposed was checked through the crossing of maps in the software GIS - Idrisi. These maps either obtained with conventional interpretation of aerial photos of 1995, digitized in the software CAD Overlay and geo-referenced in the AutoCAD Map, or with the application of digital classification systems on SPOT-XS and PAN orbital images of 1995, followed by field observations. The crossing of conventional and digital maps of a same area with the CIS allows to verify the overall results obtained through the computational handling of orbital images. With the use of digital processing techniques, specially multiespectral classification, it is possible to detect automatically and visually the impacts related to the mineral extraction, as well as to survey the land use, vegetation and environmental impacts.

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The great diversity of materials that characterizes the urban environment determines a structure of mixed classes in a classification of multiespectral images. In that sense, it is important to define an appropriate classification system using a non parametric classifier, that allows incorporating non spectral (such as texture) data to the process. They also allow analyzing the uncertainty associated to each class from the output alues of the network calculated in relation to each class. Considering these properties, an experiment was carried out. This experiment consisted in the application of an Artificial Neural Network aiming at the classification of the urban land cover of Presidente Prudente and the analysis of the uncertainty in the representation of the mapped thematic classes. The results showed that it is possible to discriminate the variations in the urban land cover through the application of an Artificial Neural Network. It was also possible to visualize the spatial variation of the uncertainty in the attribution of classes of urban land cover from the generated representations. The class characterized by a defined pattern as intermediary related to the impermeability of the urban soil presented larger ambiguity degree and, therefore, larger mixture.