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| Registros recuperados: 31 | |
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| SILVA,Camila Santos da; MENDONÇA,Bruno Araujo Furtado de; PEREIRA,Marcos Gervasio; ARAÚJO,Emanuel José Gomes de; CASTELLANI,Débora Christina. |
| ABSTRACT Geostatistics is a tool that can be used to produce maps with the distribution of nutrients essential for the development of plants. Therefore, the present study aimed to analyze the spatial variation in chemical attributes of soils under oil palm cultivation in agroforestry systems in the eastern Brazilian Amazon, and their spatial dependence pattern. Sixty spatially standardized and georeferenced soil samples were collected at each of three sampling sites (DU1, DU2, and DU3) at 0-20 cm depth. Evaluated soil chemical attributes were pH, Al3+, H+Al, K+, Ca2+, Mg2+, cation exchange capacity (CEC), P, and organic matter (OM). The spatial dependence of these variables was evaluated with a semivariogram analysis, adjusting three theoretical models... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cokriging; Ordinary kriging; Semivariogram; Soil properties. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0044-59672018000400280 |
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| CARVALHO,LAÉRCIO A. DE; MEURER,ISMAEL; JUNIOR,CARLOS A. DA SILVA; SANTOS,CRISTIANE F.B.; LIBARDI,PAULO L.. |
| When deposited on land the vinasse can promote improvement in fertility, however, often fertilizer application occurs in areas considered homogeneous, without taking into account the variability of the soil. The objective of this study was to evaluate the effect of vinasse application on potassium content in two classes of soils cultivated with sugarcane, and characterize the spatial variability of soil using geostatistical techniques. In the 2010 and 2011 crop year, soil samples were collected from an experimental grid at 0-0.2 and 0.2-0.4 m depth in three soils cultivated with sugarcane, totaling 90 samplings in each grid, for the determination of pH, calcium (Ca), magnesium (Mg), potassium (K), phosphorus (P), aluminum (Al) and potential acidity (H +... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Geostatistics; Saccharum officinarum; Semivariogram; Soil fertility. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652014000401999 |
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| Siqueira,Glécio Machado; Dafonte,Jorge Dafonte; González,Antonio Paz; Vázquez,Eva Vidal; Armesto,Monteserrat Valcarcel; Guedes Filho,Osvaldo. |
| ABSTRACT Soil sampling is an important stage of digital soil mapping. The objective of this study was to characterize the spatial design of soil sampling using soil apparent electrical conductivity (ECa) and its optimized spatial sampling. For the characterization, it was used the Spatial Simulated Annealing (SSA) technique, incorporated on the software SANOS 0.1, and the method of response surface sampling design on the software ESAP 2.35. The ECa was measured at 1,887 points in an area of 6 ha located in the northwestern region of Spain. The EM38-DD equipment (Geonics Limited 2005) was used at 2 depths: vertical dipole (1.5 m effective measurement depth) and horizontal dipole (0.75 m effective measurement depth). Semivariogram showed trend for ECa in... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Geostatistics; Semivariogram; Spatial variability; Optimization; Soil sampling. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052016000400459 |
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| Vieira,Sidney Rosa; Paz Gonzalez,Antonio. |
| The objective of this study was to assess spatial variability of soil properties and crop yield under no tillage as a function of time, in two soil/climate conditions in São Paulo State, Brazil. The two sites measured approximately one hectare each and were cultivated with crop sequences which included corn, soybean, cotton, oats, black oats, wheat, rye, rice and green manure. Soil fertility, soil physical properties and crop yield were measured in a 10-m grid. The soils were a Dusky Red Latossol (Oxisol) and a Red Yellow Latossol (Ultisol). Soil sampling was performed in each field every two years after harvesting of the summer crop. Crop yield was measured at the end of each crop cycle, in 2 x 2.5 m sub plots. Data were analysed using semivariogram... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Spatial variability; Kriging; Yield map; Semivariogram. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052003000100016 |
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| Morales,Luis Alberto; Paz-Ferreiro,Jorge; Vieira,Sidney Rosa; Vázquez,Eva Vidal. |
| The aim of this study was to describe the effect of lime additions on the spatial variability of pH and Eh in a typic Plintacualf cultivated with rice, in Corrientes, Argentina. The 5.1 ha field was divided in three sub plots at which dolomitic lime additions were made at the rates zero, 625 kg ha-1 and 1250 kg ha-1. The soil was sampled at three stages: before sowing thus in aerobic conditions, and then two more times in anaerobiosis. Ninety-six samples per sub plot were taken on each of the three sampling stages on a grid of 11.9 x 20 m. Soil pH and Eh were measured by routine methods. The pH values increased, whereas Eh values decreased, following flooding. The coefficients of variation for pH was rather low during all the three studied periods.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Semivariogram; Flooded field; Liming; Kriging. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052010000500008 |
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| Jaramillo-Barrios,Camilo Ignacio; Ortiz-Rico,Andrés Felipe; Carrillo,Gustavo Alfonso Araujo; Varón-Ramírez,Viviana Marcela. |
| ABSTRACT Soils have the ability to maintain plant growth and biological activity due to their physical and chemical properties. The aim of this study was to observe the spatial distribution of some chemical properties of the soil, such as pH, organic matter (OM), electrical conductivity (EC), effective cation exchange capacity (ECEC), sulfur (S) and aluminum (Al) content and to establish zones with homogeneous chemical characteristics using the MULTISPATI-PCA technique and the fuzzy c-means algorithm. The study area was located in the Tundama and Sugamuxi Valleys (Boyacá, Colombia) with an area of 8,017 ha. Chemical properties such as pH, OM, EC, S, Al, and ECEC were indicators of the chemical degradation of these soils. Four homogeneous zones were... |
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Palavras-chave: Geostatistics; Semivariogram; Soil degradation; Multispati-PCA; Spatial distribution.. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542019000100216 |
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| Santos,Eduardo Lucas Ensslin dos; Seidel,Enio Júnior; Pazini,Juliano de Bastos; Oliveira,Marcelo Silva de; Appel Neto,Edemar; Barbosa,Ismael Canabarro. |
| ABSTRACT: The main purpose of this article was to evaluate the behavior and relationship of the range and components of SDI (Spatial Dependence Index) in general and in function of field factors such as soil types, type of attribute and soil layers. This evaluation was based on real data collected in national journals. It was noticed that the parameter range, in general and for different field factors, presented asymmetric positive behavior. The components of the SDI showed approximately symmetrical behavior. The SDI can capture the range behavior more intensely (the spatial variability behavior in the horizontal direction of the semivariogram), and, in a less intense way, the behavior of the contribution and sill parameters (the spatial dependence... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Spatial dependence; Geostatistics; Semivariogram; Field factors. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782018000600252 |
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| Ponciano,Patrícia F.; Yanagi Junior,Tadayuki; Ferraz,Gabriel A. E S.; Scalon,João D.; Schiassi,Leonardo. |
| The air dry-bulb temperature (t db),as well as the black globe humidity index (BGHI), exert great influence on the development of broiler chickens during their heating phase. Therefore, the aim of this study was to analyze the structure and the magnitude of the t db and BGHI spatial variability, using geostatistics tools such as semivariogram analysis and also producing kriging maps. The experiment was conducted in the west mesoregion of the states of Minas Gerais in 2010, in a commercial broiler house with heating system consisting of two furnaces that heat the air indirectly, in the firsts 14 days of the birds' life. The data were registered at intervals of five minutes in the period from 8 a.m. to 10 a.m. The variables were evaluated by variograms... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Broiler chickens; Kriging; Chick; Semivariogram; Thermal stress. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162013000300001 |
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| Farias,Paulo R.S.; Roberto,Sérgio R.; Lopes,João R.S.; Perecin,Dilermando. |
| The spatial distribution of the three principal species of sharpshooter (Dilobopterus costalimai Young, Acrogonia sp. e Oncometopia facialis Signoret), vectors of Xylella fastidiosa causal agent of Citrus Variegated Chlorosis, was studied by using geostatistics. The evaluations were carried out in a commercial 'Pera' sweet orange (Citrus sinensis [L.] Osb.) grove budded on Rangpur lime (Citrus limonia Osb.) located at Bebedouro, São Paulo state, aiming to establish better means for vector and disease control. The sharpshooters were monitored using with 50 uniformly distributed 3" x 5" yellow sticky traps hanging down in branches at 1.5 m up to the ground, which were replaced monthly. Acrogonia sp. was the prevalent species sampled. The results were used to... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Citrus Variegated Chlorosis; Citrus sinensis; Semivariogram; Kriging. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1519-566X2004000100004 |
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| Farias,Paulo R.S.; Barbosa,José C.; Busoli,Antonio C.; Overal,William L.; Miranda,Vicente S.; Ribeiro,Susane M.. |
| The fall armyworm, Spodoptera frugiperda (J.E. Smith), is one of the chief pests of maize in the Americas. The study of its spatial distribution is fundamental for designing correct control strategies, improving sampling methods, determining actual and potential crop losses, and adopting precise agricultural techniques. In São Paulo state, Brazil, a maize field was sampled at weekly intervals, from germination through harvest, for caterpillar densities, using quadrates. In each of 200 quadrates, 10 plants were sampled per week. Harvest weights were obtained in the field for each quadrate, and ear diameters and lengths were also sampled (15 ears per quadrate) and used to estimate potential productivity of the quadrate. Geostatistical analyses of caterpillar... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Zea mays; Fall armyworm; Semivariogram; Kriging. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1519-566X2008000300012 |
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| Almeida,André Quintão de; Souza,Rodolfo Marcondes Silva; Loureiro,Diego Campana; Pereira,Donizete dos Reis; Cruz,Marcus Aurélio Soares; Vieira,Jodnes Sobreira. |
| Abstract: The objective of this work was to model the spatial dependence and to map the rainfall erosivity index (EI30) in the semiarid region of Brazil. Registers of monthly erosivity from 210 rainfall stations were used, with daily time series equal to or greater than 15 years. Based on the values of the EI30, a spatial dependence model was made by adjusting the semivariogram. From the semivariogram models, erosivity isoline maps were generated with a kriging interpolator. According to the historical data series, the maximum monthly average value of the EI30 was observed in March, and the annual value ranged from 1,439 to 5,864 MJ mm ha-1 per year, classified as low and moderate, respectively. The highest EI30 values were obtained in the northern and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: EI30; Geostatistics; Northeastern Brazil; Semivariogram. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2017000600371 |
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| Lambert, Dayton M.; Florax, Raymond J.G.M.; Cho, Seong-Hoon. |
| This research note documents estimation procedures and results for an empirical investigation of the performance of the recently developed spatial, heteroskedasticity and autocorrelation consistent (HAC) covariance estimator calibrated with different kernel bandwidths. The empirical example is concerned with a hedonic price model for residential property values. The first bandwidth approach varies an a priori determined plug-in bandwidth criterion. The second method is a data driven cross-validation approach to determine the optimal neighborhood. The third approach uses a robust semivariogram to determine the range over which residuals are spatially correlated. Inference becomes more conservative as the plug-in bandwidth is increased. The data-driven... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Spatial HAC; Semivariogram; Bandwidth; Hedonic model; Research Methods/ Statistical Methods; C13; C31; R21. |
| Ano: 2008 |
URL: http://purl.umn.edu/45964 |
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| Gontijo,Ivoney; Souza Dias Junior,Moacir de; Guimarães,Paulo Tácito Gontijo; Oliveira,Marcelo Silva de; Ajayi,Ayodele Ebenezer. |
| Information on the spatial structure of soil physical and structural properties is needed to evaluate the soil quality. The purpose of this study was to investigate the spatial behavior of preconsolidation pressure and soil moisture in six transects, three selected along and three across coffee rows, at three different sites under different tillage management systems. The study was carried out on a farm, in Patrocinio, state of Minas Gerais, in the Southeast of Brazil (18 º 59 ' 15 '' S; 46 º 56 ' 47 '' W; 934 m asl). The soil type is a typic dystrophic Red Latosol (Acrustox) and consists of 780 g kg-1 clay; 110 g kg-1 silt and 110 g kg-1 sand, with an average slope of 3 %. Undisturbed soil cores were sampled at a depth of 0.10-0.13 m, at three different... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Semivariogram; Soil compaction; Geostatistics; Soil sampling. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832011000400012 |
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| Registros recuperados: 31 | |
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