Variabilidade espacial de atributos químicos do solo cultivado com café arábica (Coffea arabica L.) sob diferentes manejos

The objective of this work was to assess the spatial variability of the chemical attributes of two coffee areas, managed in conventional and organic crop systems, and to calculate the percent of variation between them. In each area, a 40-point-mesh was sampled at 0-0.10 m and 0.10-0.20 m layers, within the crown projection, for pH, SB, K, P, Ca and Mg analysis. The data were analyzed through descriptive statistics and geostatistics. From the soil chemical attributes map, the percent of variation between the systems' chemical attributes was determined by GIS algebraic operations. The results show that the soil chemical attributes present a spatial dependence in both systems and layers. Analysis of the soil chemical attributes showed less spatial variability in the organic system, in relation to the conventional, indicating homogeneous zones for different fertilizer applications. The percent of variation of the chemical attributes in the conventional system, in relation to the organic, at 0-0.10 m and 0.10-0.20m layers are 54.80% and 35.61%, respectively.

Modelo agrometeorológico na estimativa da produtividade de duas variedades de café arábica considerando a variabilidade espacial

The purpose of this study was to estimate the varieties of coffee Arabic Catucáand Catuaí productivity, in Zona da Mata, Minas Gerais, through agrometeorological mathematical models, considering the spatial variability of productivity in the area. The samplings were georrefered building an irregular grid, totalizing 50 samplings per area. After that, geostatic analysis was made to quantify spatial dependence degree of the real values and the estimated productivity. According to the classification, the models superestimated the productivity for the two varieties.

Variabilidade dos atributos de um latossolo vermelho sob plantio direto no cerrado brasileiro e produtividade da soja

The spatial variability of several soil attributes (bulk density, penetration resistance, water content, organic matter content and pH) as well as soybean yield have been assessed during the 2007/08 growing season, in Selviria (MS) in a Hapludox (Typic Acrustox), under no tillage. The objectives were to assess the spatial variability of soil and plant parameters at the small plot scale and to select the best soil attribute explaining most the variability of agricultural productivity. Soil and plant were sampled on a grid with 121 points within a plot of 25,600 m 2 in area and slope of 0.025 mm -1 slope. Medium and low coefficients of variation were obtained for most of the studied soil attributes as expected, due to the homogenizing effect of the no-till system on the soil physical environment. From the standpoint of linear regression and spatial pattern of variability, productivity of soybeans could be explained according to the hydrogen potential (pH). Results are discussed taken into account that the soybean crop in no-tillage is widely used in crop-livestock integration on the national scene.

Variabilidade espacial na produção da alface em ambiente protegido

Este artigo mostra a dinâmica da água após ser aplicada sobre a superfície de um solo cultivado com alface, num sistema fechado de um ambiente protegido. A aplicação de água se deu por meio de um sistema de irrigação por gotejamento, com o CUD ( Coeficiente de Uniformidade de Distribuição ) igual a 97,06 %, o que garantiu uma ótima uniformidade de distribuição, desconsiderando como possíveis causas das variações de umidade do solo, a aplicação de lâminas variadas. Fazendo uso de técnicas de geoestatística, interpolando sessenta pontos amostrais de evaporação, umidade do solo e produtividade da alface, com as mesmas sessenta coordenadas para os três atributos, verificou-se que a umidade do solo, mesmo momentos após a irrigação, não permanece uniforme ao longo do sistema de irrigação, constatando-se que a evaporação local exerce influência de forma predominante sobre a dinâmica da água na superfície do solo. Concluiu-se que as regiões no interior da estufa de maiores evaporações, foram as de maiores variações de umidade do solo e na produção de massa verde da alface.

Variabilidade temporal no transporte de sedimentos no rio Ivaí - Paraná (1977-2007)

This paper evaluates the behavior of suspended sediment load of the river Ivaí over a period of 32 years measured by the station further downstream the river (Novo Porto Taquara). The most suitable parameters for this assessment were the annual discharge of suspended sediment and water obtained from SUDERSA. The relationship between the concentration of suspended sediment and discharge of water had not a very good correlation (R 2 = 0,56) and hysteresis effect is quite clear. The justification for this behavior is given by the heterogeneity of the hydrological regime and basin occupation. There were no significant changes in annual flows which have remained the same during the study period. Already the discharge of suspended sediment showed a small gradual decline in which the end of the period (2007), the river carries less than 0.65 Mton at the beginning (1977). This reduction in suspended sediment transported is probably due to changes in soil management for agriculture.

Variabilidade de parâmetros eletromiográficos e cinemáticos em diferentes condições de marcha em idosos

The main goal of this study was to investigate the influence of fear of fall and dual task on electromyographic and kinematic variability parameters on the gait of older females. Seventeen college students (21,47 ± 2,06 years old) and eighteen older female adults, both groups were physically fit and performed the gait test on three different conditions: walking at self-select speed, fear of fall and dual task. Electromyographic activity was measured on muscles of dominant leg and stride time was recorded. ANOVA two-way (p<0.05) was used. Electromyographic and kinematic gait variability were higher in older adult groups. However, for the comparison between gait conditions was only found significant difference for electromyographic variability. In line with this, the higher EMG and kinematic variability in older adults suggest that aging contributes for a higher motor challenge while walking, which may be predispose these individuals a higher risk of fall.

Variabilidade espacial de atributos físicos em um cambissolo háplico, sob diferentes usos na região sul do Amazonas

Considering the importance of knowledge of the spatial distribution of soil properties, the purpose of this study was to evaluate the spatial variability of physical properties in a Cambisolunder different land uses in the southern Amazon region. The study was conducted on three farms with cassava, sugarcane, and agroforestry, in the region of Humaitá, in the south of the State of Amazonas. In these areas, 70 x 70 m grids were established, with a regular spacing of 10 x 10 m and a total of 64 points, where soils were sampled at 0.0-0.10 m depth. Texture (sand, silt, and clay), macroporosity, microporosity, total porosity, bulk density, and aggregate stabilitywere determined. The data were analyzed using descriptive statistics and geostatistics. It was found that the propertiesvaried spatially and that the range of these variations between land uses was different, with the highest variability for the sugarcane management.

Variabilidade espacial dos atributos físicos em um Argissolo Vermelho sob floresta

This study aim to evaluate the spatial variability of soil physical attributes in of Alfissol forest in Manicoré region, AM. The mapping of an agroforestry growing area of 70×70m was made using a regular grid sampling of 10 × 10m. In each grid, soil samples were collected at 0.0-0.2 and 0,40-0,60 m depth, with a total of 128 sample points. Physical analyses were made (texture, soil bulk and particles density, macro and microporosity, total porosity and aggregates stability in water). With the exception of DMG, DMP and class aggregates <1.00 mm had all the physical attributes spatial dependence structure ranging from moderate to weak. Values were above the range established in the mesh (12.00 to 45.56 m), enabling to make a basis for future studies in forest area. The physical attributes presented in kriging maps different spatial behavior, however there are relationships between these attributes shown by geostatistics proving that this is effective tool for studies in forest area.

Variabilidade espacial da resistência mecânica do solo à penetração e umidade do solo em área cultivada com cana-de-açúcar na região de Humaitá, Amazonas, Brasil

The mechanical resistance to penetration (RP) is an attribute indicator of compaction was influenced by soil moisture. The objective of this study was to evaluate the spatial variability of soil resistance to penetration and soil moisture on area under cultivation of sugar cane in the region of Humaitá, Amazonas, Brazil. We conducted a sampling grid of 70x70 m where points were scored at regular intervals of 10 m, a total of 64 points. Soil samples were collected at depths of 0.00 to 0.15 m, 0.15 to 0.30 I 0.30 to 0.45 m for determination of soil moisture and soil resistance to penetration in the field. After analysis of these data analyzes were descriptive statistics and geostatistics. We conclude that all the variables studied showed spatial dependence and range values were higher than stipulated by the sampling grid and the RP and soil moisture showed a spatial relationship where lower values of PR concentrated on smaller values of soil moisture.

Variabilidade vertical de formas de fósforo em função de fontes e doses de fosfatos em semeadura direta

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

Variabilidade genética para o teor de óleo entre progênies autofecundadas de mamona (Ricinus cummunis L.) da cultivar guarani

Pós-graduação em Agronomia (Agricultura) - FCA

Desempenho de alevinos de quatro linhagens da tilápia do Nilo (Oreochromis niloticus) e análise da variabilidade genética pelos marcadores RAPD

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeitos do treinamento resistido sobre a variabilidade da frequência cardíaca, capacidade funcional e força muscular periférica na DPOC

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Variabilidade da freqüência cardíaca como ferramenta de análise da função autonômica: revisão de literatura e comparação do comportamento autonômico e metabólico em recuperação pós-exercício

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise de índices lineares e não lineares de variabilidade da frequência cardíaca de portadores de doença pulmonar obstrutiva crônica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)