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| Registros recuperados: 31 | |
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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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| Seidel,Enio Júnior; Oliveira,Marcelo Silva de. |
| 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, which served as a basis for calculation of the SDI. In view of the form of distribution and SDI descriptive measures, we developed a categorization for posterior classification of spatial dependence, specific to each... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Geostatistics; Spatial dependence; Spatial variability; Semivariogram; Summary measures. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832016000100313 |
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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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| Vieira,Sidney Rosa; Guedes Filho,Osvaldo; Chiba,Márcio Koiti; Cantarella,Heitor. |
| Assessing the spatial variability of soil chemical properties has become an important aspect of soil management strategies with a view to higher crop yields with minimal environmental degradation. This study was carried out at the Centro Experimental of the Instituto Agronomico, in Campinas, São Paulo, Brazil. The aim was to characterize the spatial variability of chemical properties of a Rhodic Hapludox on a recently bulldozer-cleaned area after over 30 years of coffee cultivation. Soil samples were collected in a 20 x 20 m grid with 36 sampling points across a 1 ha area in the layers 0.0-0.2 and 0.2-0.4 m to measure the following chemical properties: pH, organic matter, K+, P, Ca2+, Mg2+, potential acidity, NH4-N, and NO3-N. Descriptive statistics were... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Geostatistics; Soil fertility; Traditional management; Semivariogram. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832009000500041 |
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| Abreu,Paulo G. de; Dalla Costa,Osmar A.; Feddern,Vivian; Morés,Nelson; Coldebella,Arlei; Ramos,Clóvis M. C.. |
| ABSTRACT The purpose of this study was to evaluate the spatial variation of temperature, relative humidity and black globe humidity temperature (BGHT) index in growing-finishing swine facilities, with and without evaporative air cooler. The experiment was conducted in a 60 x 9 m facility containing 32 pens of 3.20 x 4.00 m each, divided into two sectors. The treatments were without evaporative air cooler (control) and with evaporative air cooler. Temperature and relative humidity data were collected weekly in two periods (morning and afternoon) at 32 different sampling points, encompassing the center of each pen and the outer perimeter of the facility. Animal performance variables were: feed intake, feed conversion, weight out of the nursery, slaughter... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Animal welfare; Spatial analyses; Environment conditions; Semivariogram. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016001101014 |
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| Souza,Zigomar M. de; Cerri,Domingos G. P.; Magalhães,Paulo S. G.; Siqueira,Diego S.. |
| Soils submitted to the same management system in places with little variation of landscape, manifest differentiated spatial variability of their attributes and crop yield. The aim of this work was to investigate the correlation between spatial variability of the soil attributes and sugarcane yield as a result of soil topography. To achieve this objective, a test area of 42 ha located at the São João Sugar Mill, in Araras, in the State of São Paulo, Brazil, was selected. Sugarcane yield was measured with a yield monitor fitted in a sugarcane harvester and GPS signal. A total of 170 soil samples were taken at regular 50 m grid, at a depth of 0 - 0.2 m. The area under study was divided into two sites based on topography. The following soil attributes were... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Saccharum sp; Geostatistics; Semivariogram; Curvature; Precision agriculture. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662010001200001 |
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| BRITO,RAIMUNDO DIONÍZIO PINTO; FARIAS,PAULO ROBERTO DA SILVA; RODRIGUES,NARA ELISA LOBATO; OLIVEIRA,FABIO JÚNIOR DE; TEXEIRA,RENATO ALVES. |
| ABSTRACT The production of biofuels from native Amazonian palm trees, belonging to the family of Arecaceae, like Attalea maripa (Aubl) Mart. (Maripa palm), are objects of studies of alternative energy sources for the biofuels production. Thus, the aim of this research was to evaluate the spatial dynamics of agronomic variables of Maripa palm crop production associated with the characteristics of the sampling sites in a spontaneous growth area in the Low Tocantins region. 100 palms of A. maripa were selected, of spontaneous growth and in production phase, on a 10 ha area in the municipality of Cametá / PA, in which the morpho-agronomical variables were collected (MIN, FIN, ABN, LN, DBH, AWAB and AFW), from January 2014 to June 2014. The semivariograms were... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Spatial dependence; Maripa palm; Kriging; Semivariogram; Variables morphoagronomics. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-29452017000300903 |
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| Silva,Kátia Araújo da; Rodrigues,Marcos Sales; Moreira,Filipe Bernard Ramos; Lira,Aíris Layanne Ferreira; Lima,Augusto Miguel Nascimento; Cavalcante,Ítalo Herbert Lucena. |
| Abstract Soil sampling is a fundamental procedure in the decision making regarding the management of the soil, thus, a sampling plan should represent as accurately as possible the evaluated crop field. Therefore, the objectives of this study were to suggest a soil sampling approach and soil sampling point allocation using spatial analyses and compare to the classic statistic method in irrigated mango orchards in the Brazilian semi-arid region. The experiment was carried out in three commercial mango orchards located in the region of the São Francisco Valley, Brazil. Soil samples were collected in 0-0.2 m and 0.2-0.4 m depths following regular grids where the number of samples varied from 50 to 56. Soil texture, soil bulk density, soil total porosity,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Geostatistics; Mangifera indica L; Semivariogram; Spatial dependence. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-29452020000503003 |
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| Lima,Julião Soares de Sousa; Alves,Danielle Inácio; Coelho,Ruimário Inácio; Sturião,Walas Permanhane; Silva,Samuel Assis. |
| ABSTRACT Leaf analysis is widely used to study the nutritional status of plants, based on the fact of there being a direct correlation between rate of growth and the nutrient levels in leaf tissue. This study was carried out on a commercial crop of Golden THB papaya, in the north of the State of Espirito Santo, Brazil, to determine the spatial variability of nutrients in the petiole of leaf samples collected when carrying out sexing in a regular grid of 129 georeferenced points. Harvesting was carried out manually 270-365 days after transplanting. All the characteristics displayed a strong spatial dependence, the spherical and exponential semivariograms being adjusted for the data. The greatest and smallest ranges were found for the micronutrients Mn and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Geostatistics; Semivariogram; Leaf petiole. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902016000200264 |
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| Vendrusculo,Laurimar Gonçalves; Magalhães,Paulo Sérgio Graziano; Vieira,Sidney Rosa; Carvalho,José Ruy Porto de. |
| Geostatistics identifies the spatial structure of variables representing several phenomena and its use is becoming more intense in agricultural activities. This paper describes a computer program, based on Windows Interfaces (Borland Delphi), which performs spatial analyses of datasets through geostatistic tools: Classical statistical calculations, average, cross- and directional semivariograms, simple kriging estimates and jackknifing calculations. A published dataset of soil Carbon and Nitrogen was used to validate the system. The system was useful for the geostatistical analysis process, for the manipulation of the computational routines in a MS-DOS environment. The Windows development approach allowed the user to model the semivariogram graphically... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Spatial variability; Semivariogram; Software. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162004000100017 |
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| Grego,Célia Regina; Vieira,Sidney Rosa; Antonio,Aline Maria; Della Rosa,Simone Cristina. |
| Experiments in agriculture usually consider the topsoil properties to be uniform in space and, for this reason, often make inadequate use of the results. The objective of this study was to assess the variability for soil moisture content using geostatistical techniques. The experiment was carried out on a Rhodic Ferralsol (typic Haplorthox) in Campinas, SP, Brazil, in an area of 3.42 ha cultivated under the no tillage system, and the sampling was made in a grid of 102 points spaced 10 m x 20 m. Access tubes were inserted down to one meter at each evaluation point in order to measure soil moisture contents (cm³ cm-3) at depths of 30, 60 and 90 cm with a neutron moisture gauge. Samplings were made between the months of August and September of 2003 and in... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Neutron moisture gauge; Semivariogram; Spatial and temporal variability. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162006000400005 |
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| Registros recuperados: 31 | |
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