Spatial Variability Of Physical Attributes Research Articles

Spatial variability of physical attributes of a Oxisol related to garlic productivity

Garlic is a product with high demand in Brazil and worldwide, being highly valued in the cuisine of several countries and is a culture with high added economic value. In 2018, this work was carried out in the irrigation and drainage area of the Federal University of Viçosa, in Viçosa, Minas Gerais State, Brazil, in a Oxisol. The objective was to characterize the structure and magnitude of the spatial distribution of physical attributes of a Oxisol, perform the mapping, and evaluate the spatial correlation between garlic bulb yield, lateral shoot growing and soil characteristics. The attributes studied were garlic bulb yield, lateral shoot growing, soil moisture on a dry basis, soil moisture on a humid basis, volumetric soil moisture, particle density, free soil porosity, sampled in a 90-georeferenced grid. Data analysis using statistical techniques and geostatistics made it possible to verify that the garlic yield and other soil physical attributes studied showed spatial dependence. There was an emphasis on the spatial correlation between garlic bulb yield and free-soil porosity. The lateral shoot growing of garlic has a direct and positive relationship with free soil porosity, soil moisture on a dry basis and soil moisture on a humid basis.

Physical soil attributes in areas under forest/pasture conversion in northern Rondônia, Brazil.

The main cause of physical degradation in pasture areas is overgrazing, and when combined with poorly productive soils, it causes the loss of millions of hectares of agricultural soils a year. Thus, work is needed to indicate which physical attributes are most sensitive to degradation, generating information so that soil management can be proposed, with a view to economic, social, and environmental aspects. Therefore, the objective of the work was to evaluate the impacts caused on the physical attributes of the soil, in forests converted to pastures in northern Rondônia, Brazil. The study was carried out in three areas within the municipality of Porto Velho, Rondônia, one area with forest and two with pastures (brachiaria and mombaça grass). In the field, deformed soil samples were collected at a depth of 0.00-0.10 and 0.10-0.20m in the three study areas. In the laboratory, physical analyses of texture, aggregates and porosity, compaction, and an additional analysis of soil organic carbon were carried out. Then, univariate, bivariate, and multivariate analyses were performed, as well as geostatistical analysis. The conversion of forest to pasture had a negative impact on aggregates, compaction, porosity, and accumulation of organic carbon in the soil. The studied environments are influenced by the high levels of sand and clay, which interfere in the aggregation, compaction, porosity, and accumulation of organic carbon in the soil. We observed greater spatial variability of physical attributes in the environment with mombaça grass and attributed this to the greater grazing and trampling intensity of the animals.

Moisture Behavior to the Spatial Variability of Physical Attributes in Different Soil Management

Moisture Behavior to the Spatial Variability of Physical Attributes in Different Soil Management

Spatial distribution of physical attributes of an Ultisol under papaya crop

The successful development of the root system of plants depends on the favorable conditions of soil physical attributes. The objective of this work was to study the spatial variability of physical attributes in an Ultisol cultivated with papaya. The soil was prepared mechanically plowing, harrowing, sulcal and subsoiler. In the center of the crop field was built a sampling grid with points spaced 5.7 m, totalizando129 georeferenced points. The soil samples at two depths (0 - 0.20 m, 0.20 - 0.40 m) were collected for four months after transplantation, to determine the total porosity (TP), soil moisture (Um), soil bulk density (BD) and soil penetration resistance in the planting row (PRPR) and in the traffic machines rows (PRRow). The soil penetration resistance in the planting row and in the traffic machines row was determined. The BD1 and BD2 showed the lowest CV values, and the data were fitted to the exponential and spherical models, respectively, with spatial dependence ranges of 20 and 28 m. At the layer of 0-0.20 m depth, the attributes showed the same spatial distribution pattern. At the layer of 0-0.20 m depth, the soil penetration resistance showed 7.5 times greater in the traffic machines region (rw spacing) than the value found in the planting row.

Variabilidade espacial de atributos físicos do solo em terra preta de índio sob cultivo de café conilon

A conversão de ecossistemas naturais em sistemas agrícolas provoca alterações significativas nos atributos do solo, associado ao crescente desmatamento na região amazônica influenciando a desestabilidade do ecossistema. Dessa forma, objetivou-se com este estudo avaliar a variabilidade espacial dos atributos físicos do solo em área de terra preta de índio (TPI) sob cultivo de café Conilon. Foi demarcado um grid amostral com dimensões de 88 × 64 m, com espaçamento regular de 8 m, perfazendo um total de 88 pontos amostrais. Foram coletadas amostras estruturadas e indeformadas nas camadas de 0,00-0,05; 0,05-0,10; 0,10-0,20 e 0,20-0,30 m. Realizaram-se as seguintes análises físicas: granulometria, estabilidade de agregados, carbono orgânico total (COT), estoque de carbono (EstC), macroporosidade (MaP), microporosidade (MiP), densidade do solo (Ds), porosidade total (PT), resistência do solo à penetração (RP) e umidade volumétrica (θ). Os resultados foram submetidos à análise estatística descritiva e geoestatística. As TPI’s apresentam grande potencial que podem subsidiar o aumento na produção, visto que estes solos apresentam excelente condição que se refere aos atributos físicos, sendo que nas camadas avaliadas estes não apresentaram nenhuma restrição e impedimento ao sistema radicular da cultura.

Spatial variability of physical attributes of Alfissol under agroforestry in Humaitá region, AM

Spatial variability of physical attributes of Alfissol under agroforestry in Humaitá region, AM

Spatial variability of physical attributes of a clayey latosol related to the grain yield of the crambe (Crambe abyssinica Hochst) culture

The aim of this study was to determine, with the help of thematic maps obtained by kriging interpolation, the existence of relationship between spatial variability of soil density and soil resistance to penetration with crambe yield (Crambe abyssinica) under no-tillage system on clayey Latosol. The experiment was conducted in experimental area located in Cascavel-Parana, Brazil. The experimental grid was established in 100 × 100 m area, totaling 100 points, in which samples of soil density and soil resistance to penetration were collected in order to relate them to the productivity of the crambe culture. The values results showed that the soil density and soil resistance to penetration, in all studied layers (0 to 0.1, 0.1 to 0.2 and 0.2 to 0.3 m), did not present significant values of compressed areas. After analysis of the thematic maps, one could note that there was no relation between the soil density and soil resistance to penetration with respect to yield of crambe culture. Among the attributes studied in this work, the soil resistance to penetration in the layer of 0 to 0.1 m was the one that showed greatest relation to productivity to crambe. Key words: Energetic cultures, geostatistics, bulk density.

Variabilidade espacial de atributos físicos em solos de vale aluvial no semiárido de Pernambuco

As características físicas e hidráulicas do solo se constituem em condicionantes a planos de manejo agrícola. Objetivou-se avaliar atributos físicos em solos de um vale aluvial e sua variabilidade, no semiárido do Estado de Pernambuco, na bacia hidrográfica do Rio Ipanema. Técnicas estatísticas e geoestatísticas foram utilizadas a fim de se investigar o grau de dependência e a variabilidade espacial dos atributos, em lotes de agricultura familiar. O coeficiente de variação apresentou-se alto para a condutividade hidráulica do solo e médio para a resistência à penetração de raízes e para as frações granulométricas areia, argila e silte. Tal coeficiente foi baixo para a densidade do solo e de partículas e porosidade total. Foram investigadas as estruturas de dependência espacial para as variáveis estudadas, encontrando-se alcances variando de 135 m para a condutividade hidráulica a 465 m para o conteúdo de silte. Mapa de isolinhas foi elaborado por krigagem representando a variabilidade espacial da condutividade hidráulica, com moderado grau de dependência espacial. As frações granulométricas areia total e silte (%) também apresentaram grau de dependência espacial moderado. A resistência à penetração, densidade do solo e de partículas, não apresentaram dependência espacial na escala de investigação adotada. Foi possível identificar regiões de maior aptidão agrícola verificando-se, através do mapeamento, que os solos francos tendem a apresentar elevada resistência à penetração e baixa condutividade hidráulica.

Variabilidade espacial das frações primárias e agregados de um Argissolo no estado do Ceará

A variabilidade espacial tem sido uma das preocupações de estudiosos desde o inicio do século, sendo o sistema de manejo do solo um fator que interfere na distribuição espacial das propriedades físicas do mesmo. O objetivo do trabalho foi caracterizar e determinar a variabilidade espacial de atributos físicos de um Argissolo Amarelo, utilizando métodos geoestatísticos e confecção de mapas de superfície pelo método da Krigagem, em duas camadas de solo. Foram realizadas coletas de solo em intervalos regulares de 2,5 m numa área de 400 m², sendo 81 pontos em cada uma das camadas (0-0,2 m e 0,2-0,4 m), totalizando 162 amostras que foram submetidas às determinações físicas e os dados obtidos analisados pela estatística descritiva para verificar a normalidade da distribuição de freqüência e posteriormente submetidos à geoestatística. O modelo de semivariograma que melhor se ajustou aos dados, na maioria das variáveis, foi o esférico. Verificou-se efeito pepita puro para as variáveis grau de floculação, na profundidade de 0-0,2 m e os agregados estáveis, na profundidade de 0,2-0,4 m.

Spatial variability of physical attributes of an alfisol under different hillslope curvatures

The influence of relief forms has been studied by several authors and explains the variability in the soil attributes of a landscape. Soil physical attributes depend on relief forms, and their assessment is important in mechanized agricultural systems, such as of sugarcane. This study aimed to characterize the spatial variability in the physical soil attributes and their relationship to the hillslope curvatures in an Alfisol developed from sandstone and growing sugarcane. Grids of 100 x 100 m were delimited in a convex and a concave area. The grids had a regular spacing of 10 x 10 m, and the crossing points of this spacing determined a total of 121 georeferenced sampling points. Samples were collected to determine the physical attributes related to soil aggregates, porosity, bulk density, resistance to penetration and moisture within the 0-0.2 and 0.2-0.4 m depth. Statistical analyses, geostatistics and Student's t-tests were performed with the means of the areas. All attributes, except aggregates > 2 mm in the 0-0.2 m depth and macroporosity at both depths, showed significant differences between the hillslope curvatures. The convex area showed the highest values of the mean weighted diameter, mean geometric diameter, aggregates > 2 mm, 1-2 mm aggregates, total porosity and moisture and lower values of bulk density and resistance to penetration in both depth compared to the concave area. The number of soil attributes with greater spatial variability was higher in the concave area.