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.

Delineation of specific management areas for coffee cultivation based on the soil-relief relationship and numerical classification

Predicting and mapping productivity areas allows crop producers to improve their planning of agricultural activities. The primary aims of this work were the identification and mapping of specific management areas allowing coffee bean quality to be predicted from soil attributes and their relationships to relief. The study area was located in the Southeast of the Minas Gerais state, Brazil. A grid containing a total of 145 uniformly spaced nodes 50 m apart was established over an area of 31. 7 ha from which samples were collected at depths of 0. 00-0. 20 m in order to determine physical and chemical attributes of the soil. These data were analysed in conjunction with plant attributes including production, proportion of beans retained by different sieves and drink quality. The results of principal component analysis (PCA) in combination with geostatistical data showed the attributes clay content and available iron to be the best choices for identifying four crop production environments. Environment A, which exhibited high clay and available iron contents, and low pH and base saturation, was that providing the highest yield (30. 4l ha-1) and best coffee beverage quality (61 sacks ha-1). Based on the results, we believe that multivariate analysis, geostatistics and the soil-relief relationships contained in the digital elevation model (DEM) can be effectively used in combination for the hybrid mapping of areas of varying suitability for coffee production. © 2012 Springer Science+Business Media New York.

Quantification of uncertainties associated with space-time estimates of short-term soil CO2 emissions in a sugar cane area

The characterization of soil CO2 emissions (FCO2) is important for the study of the global carbon cycle. This phenomenon presents great variability in space and time, a characteristic that makes attempts at modeling and forecasting FCO2 challenging. Although spatial estimates have been performed in several studies, the association of these estimates with the uncertainties inherent in the estimation procedures is not considered. This study aimed to evaluate the local, spatial, local-temporal and spatial-temporal uncertainties of short-term FCO2 after harvest period in a sugar cane area. The FCO2 was featured in a sampling grid of 60m×60m containing 127 points with minimum separation distances from 0.5 to 10m between points. The FCO2 was evaluated 7 times within a total period of 10 days. The variability of FCO2 was described by descriptive statistics and variogram modeling. To calculate the uncertainties, 300 realizations made by sequential Gaussian simulation were considered. Local uncertainties were evaluated using the probability values exceeding certain critical thresholds, while the spatial uncertainties considering the probability of regions with high probability values together exceed the adopted limits. Using the daily uncertainties, the local-spatial and spatial-temporal uncertainty (Ftemp) was obtained. The daily and mean emissions showed a variability structure that was described by spherical and Gaussian models. The differences between the daily maps were related to variations in the magnitude of FCO2, covering mean values ranging from 1.28±0.11μmolm-2s-1 (F197) to 1.82±0.07μmolm-2s-1 (F195). The Ftemp showed low spatial uncertainty coupled with high local uncertainty estimates. The average emission showed great spatial uncertainty of the simulated values. The evaluation of uncertainties associated with the knowledge of temporal and spatial variability is an important tool for understanding many phenomena over time, such as the quantification of greenhouse gases or the identification of areas with high crop productivity. © 2013 Elsevier B.V.

Correlação espacial do índice de vegetação (NDVI) de imagem Landsat/ETM+ com atributos do solo

The precision agriculture technologies such as the spatial variability of soil attributes have been widely studied mostly with sugarcane. Among these technologies have been recently highlighted the use of the vegetation index derived from remote sensing products, such as powerful tools indicating the development of vegetation. This study aimed to analyze the spatial variability of clay content, pH and phosphorus in an Oxisol in an area with sugarcane production, and correlate with the Normalized Difference Vegetation Index (NDVI). The georeferenced grid was created for the soil properties (clay, phosphorus and pH) and generated the maps of spatial variability. For these same sites were calculated the NDVI, in addition to mapping of this ratio, the evaluation of the spatial correlation between this and other studied properties. The clay and phosphorus content showed positive spatial correlation with the NDVI, while no spatial correlation was observed between NDVI and pH. The satellite images from the sensor ETM + Landsat were used to correlate to NDVI to observe the spatial variability of the studied attributes.

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.

Influência do relevo e erodibilidade nos atributos químicos em área degradada de Gilbués, PI

Soil degradation can be defined as a process that reduces the ability of soil to produce property or services. Thus, the objective was to study the influence of topography and erodibility in the distribution of the chemical attributes of an Alfissol in degraded areas of Gilbués in the State of Piaui, Brazil. In the chosen area a sampling grid of 1 ha was demarcated, with points spaced at 10 x 10 m, and 121 samples were collected at intersections, in 0-0.20 m depth. Each point was georeferenced as a way to demarcate the area and prepare a topography map. For all samples pH, organic matter, phosphorus, potassium, calcium, magnesium, hydrogen and aluminum were determined. The estimate of erodibility was calculated from the equation proposed by Denardin. Based on the experiment and the results obtained it is concluded that the number of samples used was sufficient to determine the variability of soil in degraded areas of the Gilbués municipality. The discontinuity in the topography of the landscape and erodibility cause a moderate degree of heterogeneity in most chemical properties of the studied soil, establishing specific management zones.

Avaliação limnológica em um sistema de piscicultura na região de Paranaíta (MT, Brasil)

Pós-graduação em Aquicultura - FCAV

Identificação do teor de nitrogênio foliar em cana-de-açúcar no estágio inicial de crescimento utilizando infravermelho próximo e sistemas inteligentes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Correlação espacial entre os atributos do solo e o índice espectral de vegetação na cultura de cana-de-açúcar

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Métodos geoestatísticos na caracterização espacial de óxidos de ferro em diferentes pedoformas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Incertezas na estimativa da variabilidade espacial da emissão de CO2 do solo e propriedades edáficas em área de cana crua

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Suscetibilidade magnética na identificação de compartimentos da paisagem e indicador de qualidade do solo em áreas sob cultivo de cana-de-açúcar

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização de solos sob diferentes ambientes na região Sul do Amazonas

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