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Geochemistry and Spatial Variability of Rare Earth Elements in Soils under Different Geological and Climate Patterns of the Brazilian Northeast

Cinthia Maria Cordeiro Atanázio Cruz Silva, Ronny Sobreira Barbosa, Clístenes Williams Araújo do Nascimento, Yuri Jacques Agra Bezerra da Silva, Ygor Jacques Agra Bezerra da Silva


ABSTRACT Growth in the agricultural and industrial sectors has increased the demand for rare earth elements (REEs) in the production of technological devices and fertilizers. Thus, the accumulation of these elements in the soil has become an environmental concern. Here, we aim to determine the natural contents of REEs in soils derived from different parent materials and under climatic conditions ranging from humid to semi-arid. We then evaluate the influence of major elements and soil properties on the geochemistry of […]

Temporal and Spatial Uncertainty of Erosion Soil Loss from an Argisol Under Sugarcane Management Scenarios

Patrícia Gabarra Mendonça, Daniel De Bortoli Teixeira, Mara Regina Moitinho, João Fernandes da Silva, Ismênia Ribeiro de Oliveira, Marcílio Vieira Martins, [...]


ABSTRACT The identification of erosion-susceptible areas is fundamental for the adoption of soil conservation practices. Thus, the best way to estimate the spatial pattern of soil erosion must be identified, in which the process uncertainties are also taken into consideration. The purpose of this study was to evaluate the spatial and temporal uncertainty of soil loss under two scenarios of sugarcane harvest management: green cane (GC) and burnt cane (BC). The study was carried out on a 200-ha area, in […]

Spatial Variability of Soil Fauna Under Different Land Use and Managements

Raimunda Alves Silva, Glécio Machado Siqueira, Mayanna Karlla Lima Costa, Osvaldo Guedes, Ênio Farias de França e Silva


ABSTRACT Geostatistics allows the evaluation of the distribution pattern of data with high spatial variability in agricultural systems. This study aimed to evaluate the spatial variability of biological diversity indices of soil fauna under different land (agriculture and forest). Samples were collected in seven areas (millet, soybean, corn, eucalyptus, pasture crops, and preserved and disturbed Cerrado), in Maranhão state, Brazil. The soil fauna was caught trapped in pitfall traps, installed 3 m away from each other. In each area, 130 […]

Spatial Distribution of Annual and Monthly Rainfall Erosivity in the Jaguarí River Basin

Lucas Machado Pontes, Marx Leandro Naves Silva, Diêgo Faustolo Alves Bispo, Fabio Arnaldo Pomar Avalos, Marcelo Silva de Oliveira, Humberto Ribeiro da Rocha


ABSTRACT The Jaguarí River Basin forms the main water supply sources for the São Paulo Metropolitan Region and other cities in the state. Since the kinetic energy of rainfall is the driving force of water erosion, the main cause of land and water degradation, we tested the hypothesis of correlation between the erosive potential of rainfall (erosivity) and geographical coordinates and altitude for the purpose of predicting the spatial and temporal distribution of the rainfall erosivity index (EI30) in the […]

Sampling Design of Soil Physical Properties in a Conilon Coffee Field

Eduardo Oliveira de Jesus Santos, Ivoney Gontijo, Marcelo Barreto da Silva, Fábio Luiz Partelli


ABSTRACT Establishing the number of samples required to determine values of soil physical properties ultimately results in optimization of labor and allows better representation of such attributes. The objective of this study was to analyze the spatial variability of soil physical properties in a Conilon coffee field and propose a soil sampling method better attuned to conditions of the management system. The experiment was performed in a Conilon coffee field in Espírito Santo state, Brazil, under a 3.0 × 2.0 […]

A Classification for a Geostatistical Index of Spatial Dependence

Enio Júnior Seidel, Marcelo Silva de Oliveira


ABSTRACT: In geostatistical studies, spatial dependence can generally be described by means of the semivariogram or, in complementary form, with a single index followed by its categorization to classify the degree of such dependence. The objective of this study was to construct a categorization for the spatial dependence index (SDI) proposed by Seidel and Oliveira (2014) in order to classify spatial variability in terms of weak, moderate, and strong dependence. Theoretical values were constructed from different degrees of spatial dependence, […]

Fuzzy Classification in the Determination of Input Application Zones

Julião Soares de Souza Lima, Felipe Pianna Costa, Alexandre Cândido Xavier, Samuel de Assis Silva


ABSTRACT Correctly interpreting soil fertility and its spatial distribution within an area helps to lessen losses and environmental effects associated with agriculture, to optimize fertilization and liming practices. This study is aimed at using concepts and methods from spatial and temporal analyses to soil fertility and to develop a fuzzy classification methodology in an effort to define input application zones in three conilon coffee harvests. An irregular network with georeferenced points was built in the central region of the farm. […]


James Ribeiro de Azevedo, Célia Regina Paes Bueno, Gener Tadeu Pereira


ABSTRACT The study of soil chemical and physical properties variability is important for suitable management practices. The aim of this study was to evaluate the spatial variability of soil properties in the Malhada do Meio settlement to subsidize soil use planning. The settlement is located in Chapadinha, MA, Brazil, and has an area of 630.86 ha. The vegetation is seasonal submontane deciduous forest and steppe savanna. The geology is formed of sandstones and siltstones of the Itapecuru Formation and by […]

Spatial Variability of Resistance to Penetration in an Eutrophic Udorthent

Fabriciano da Cunha Corado, Fabricio de Menezes Telo Sampaio, Marcos Emanuel da Costa Veloso, Sammy Sidney Rocha Matias, Fabricio Ribeiro Andrade, Marcio Godofredo Rocha Lobato


ABSTRACT Resistance to penetration allows evaluation of soil behavior in relation to the management practices adopted. The aim of the present study was to analyze the behavior of resistance to penetration in the dry and rainy season by spatial variability in a degraded area in Gilbués, PI, Brazil. The study was conducted in a 4-ha experimental area, belonging to Embrapa Meio Norte, in 2010/2011. Soil in the area is a Neossolo Litólico Eutrófico (Udorthent) with exposure of the C horizon. […]


Patrícia Gabarra Mendonça, João Fernandes da Silva, Ismênia Ribeiro de Oliveira, Daniel De Bortoli Teixeira, Mara Regina Moitinho, Marcílio Vieira Martins, [...]


The assessment of spatial uncertainty in the prediction of nutrient losses by erosion associated with landscape models is an important tool for soil conservation planning. The purpose of this study was to evaluate the spatial and local uncertainty in predicting depletion rates of soil nutrients (P, K, Ca, and Mg) by soil erosion from green and burnt sugarcane harvesting scenarios, using sequential Gaussian simulation (SGS). A regular grid with equidistant intervals of 50 m (626 points) was established in the […]

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