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| Registros recuperados: 73 | |
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| Santos,Railton O. dos; Franco,Laís B.; Silva,Samuel A.; Sodré,George A.; Menezes,Agna A.. |
| ABSTRACT The knowledge on the spatial variability of soil properties and crops is important for decision-making on agricultural management. The objective of this study was to evaluate the spatial variability of soil fertility and its relation with cocoa yield. The study was conducted over 14 months in an area cultivated with cocoa. A sampling grid was created to study soil chemical properties and cocoa yield (stratified in season, off-season and annual). The data were analyzed using descriptive and exploratory statistics, and geostatistics. The chemical attributes were classified using fuzzy logic to generate a soil fertility map, which was correlated with maps of crop yield. The soil of the area, except for the western region, showed possibilities ranging... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Precision agriculture; Cocoa; Spatial variability; Fuzzy logic. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662017000200088 |
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| Bottega,Eduardo L.; Queiroz,Daniel M. de; Pinto,Francisco A. C.; Oliveira Neto,Antonio M. de; Vilar,Cesar C.; Souza,Cristiano M. A. de. |
| The objective of this study was to evaluate the influence of different sampling grids density in the lime requirements in an Oxisol. The experiment was conducted at a rural property located in Sidrolândia city, Mato Grosso do Sul state, in the Brazilian ‘Cerrado’. In the soil attributes mapping, regular sampling grid was used consisting of 99 points, spread over an area of 90 ha. Other two grids (51 and 27 points) were derived by deleting lines or lines and points from the original one. Based on the results of soil analysis, the lime requirement at each sample point was calculated. Using geostatistical techniques the spatial variability of lime requirement was studied and grid configuration for each sample was tested. By kriging, maps were made. By... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Precision agriculture; Geostatistics; Spatial variability; Soil acidity correction. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662014001100008 |
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| Spezia,Graciele R.; Souza,Eduardo G. de; Nóbrega,Lúcia H. P.; Uribe-Opazo,Miguel A.; Milan,Marcos; Bazzi,Claudio L.. |
| Yield mapping represents the spatial variability concerning the features of a productive area and allows intervening on the next year production, for example, on a site-specific input application. The trial aimed at verifying the influence of a sampling density and the type of interpolator on yield mapping precision to be produced by a manual sampling of grains. This solution is usually adopted when a combine with yield monitor can not be used. An yield map was developed using data obtained from a combine equipped with yield monitor during corn harvesting. From this map, 84 sample grids were established and through three interpolators: inverse of square distance, inverse of distance and ordinary kriging, 252 yield maps were created. Then they were compared... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Precision agriculture; Thematic map; Spatial variability. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662012000400016 |
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| Gonçalves,Luana M.; Ferraz,Gabriel A. e S.; Oliveira,Marcelo S. de; Barbosa,Brenon D. S.; Silva,Carlos J. da; Ferraz,Patrícia F. P.. |
| ABSTRACT Noise is one of the harmful and stressful physical agents present in the workplace. Research performed with geostatistics to adjust the semivariogram of tractor noise were performed using the Gaussian and spherical model. In this way, the aim was to map the spatial variability of the noise emitted by a power tiller through the sine wave model, besides testing other fitting methods, in order to identify health zones for the workers. The experiment was performed with an agricultural power tiller (10.3 kW) placed in a working regime (1500 rpm), coupled to a brushcutter, and a digital sound level meter to collect noises in points distributed along a regular grid sampling of 2.0 × 2.0 m around the tractor. The spatial dependence of noise was analyzed... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Acoustic comfort; Agricultural mechanization; Spatial variability; Ergonomics; Sine wave model. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662019000300223 |
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| Paris,Jaqueline O.; Gontijo,Ivoney; Partelli,Fábio L.; Facco,Alexandro G.. |
| ABSTRACT Soil fertility is the key to agricultural production. The spatial correlation and location of nutrients may significantly affect the yields. The objective of this work was to evaluate the variability and spatial correlation of iron (Fe), copper (Cu), manganese (Mn), zinc (Zn), and organic matter (OM) with macadamia nut yield. The study was conducted in an Oxisol cultivated for 20 years with macadamia nut in São Mateus, state of Espírito Santo, Brazil. A 100 point grid was used comprising an area of 144 × 140 m with a minimum distance between points of 5 m, in which a single composite soil sample was collected from 0-0.20 m layer for chemical analysis of Fe, Cu, Mn, Zn and OM. Nuts under the canopy’s projection were harvested from February to June,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Macadamia integrifolia; Spatial variability; Geostatistics; Plant nutrition. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662020000100031 |
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| Carvalho,Luis C. C.; Silva,Fabio M. da; Ferraz,Gabriel A. e S.; Stracieri,Juliana; Ferraz,Patrícia F. P.; Ambrosano,Lucas. |
| ABSTRACT To make the coffee activity competitive, some farmers use precision coffee farming. Thus, it is possible to create thematic maps that guide management practices for regions where there are limitation for the plant development. The objective of this study was to identify the spatial dependence of coffee crop yield, in 2012 and 2013. The experimental area is located in a Haplustox in Três Pontas, Minas Gerais. One hundred sampling points were georeferenced for the collection of yield data through manual harvest. The difference of yield between crop seasons was also evaluated. Data were processed using geostatistical analysis. It was possible to identify and characterize the spatial dependence of all variables, as well as to create contour maps.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coffea arabica L.; Spatial variability; Biennuality; Maps; Precision agriculture. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662017000600410 |
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| Silva,Samuel de Assis; Queiroz,Daniel Marçal de; Pinto,Francisco de Assis de Carvalho; Santos,Nerilson Terra. |
| Differentiating coffees through the notion of terroirs allows us to determine potential areas for specialty coffee production and to characterize the type of coffee in these areas, exploring their potential. The objective of this work was to study spatial variability quality and to characterize and delimit terroirs in coffee crop production in Araponga municipality, Minas Gerais State, Brazil, using sensorial evaluation. The data were collected from four crops, from altitudes ranging from 770 to 1270 m, with the extract increasing from low to high. In each plot of crops, samples of cherry fruits were collected, dried, benefited, subjected to sensorial analysis and given grades ranging from 0 to 100 points for the global drink quality and relative... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Geographical origin; Sensorial quality; Spatial variability. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902014000100003 |
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| Barbosa,Danilo Pereira; Bottega,Eduardo Leonel; Valente,Domingos Sárvio Magalhães; Santos,Nerilson Terra; Guimarães,Wellington Donizete; Ferreira,Matheus de Paula. |
| ABSTRACT The proper handling soil allows the reduction of contaminants, maximize agricultural productivity, and is directly related the knowledge spatial variability of soil attributes. This spatial variability can express isotropic and anisotropic form. The latter being neglected in research related to management zones delineation. In this context, the present study aimed to evaluate the effect of the geometric anisotropy correction on the management zone delineation. The methodology was applied under database of soybean productivity and apparent electrical conductivity (CEa) of a rural property in Ponta Porã - MS. By means of this georeferenced database, maps was interpolated with ordinary kriging. For each combination, attribute (productivity and CEa)... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Geostatistics; Anisotropy factor; Spatial variability; Apparent electrical conductivity; Soybean. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902019000400543 |
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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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| Sadeghi,Morteza; Ghahraman,Bijan; Davary,Kamran; Hasheminia,Seyed Majid; Reichardt,Klaus. |
| Using scaling methods, a single solution of Richards' equation (RE) will suffice for numerous specific cases of water flow in unsaturated soils. In this study, a new method is developed to scale RE for the soil water redistribution process. Two similarity conditions are required: similarity in the shape of the soil water content profiles as well as of the water flux density curves. An advantage of this method is that it is not restricted to a specific soil hydraulic model - hence, all such models can be applied to RE. To evaluate the proposed method, various soil textures and initial conditions were considered. After the RE was solved numerically using the HYDRUS-1D model, the solutions were scaled. The scaled soil water content profiles were nearly... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Nielsen-similarity; Spatial variability; Invariant solutions. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162011000500011 |
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| Reichardt,Klaus; Silva,José Carlos de Araújo; Bassoi,Luis Henrique; Timm,Luís Carlos; Oliveira,Julio Cesar Martins de; Bacchi,Osny Oliveira Santos; Pilotto,João Eduardo. |
| The effects of soil water spatial variability previous to irrigation and of the field capacity on the estimation of irrigation water depth are evaluated. The experiment consisted of a common bean (Phaseolus vulgaris L.) crop established on a Kandiudalfic Eutrudox of Piracicaba, SP, Brazil, irrigated by central pivot, in which soil water contents were evaluated with a depth neutron gauge, in a grid of 20x4 points with lag of 0.5 m. In a given situation, the 80 calculated irrigation water depths presented a coefficient of variation of 29.3%, with an average water value of 18 mm, maximum of 41mm and minimum of 9 mm. It is concluded that the only practical way of irrigation is the use of an average water depth, due to the inherent variability of the soil, and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Irrigation water depth; Field capacity; Spatial variability. |
| Ano: 2001 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162001000300017 |
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| Dinardo-Miranda,Leila Luci; Fracasso,Juliano Vilela. |
| Nematodes are important parasites of sugarcane in Brazil. Because of this, several studies have been conducted in recent years to evaluate the effectiveness of control methods. However, no studies have been reported on the spatial distribution of nematodes in sugarcane fields, and such studies are indispensable for the development of sampling plans, aimed at their application in integrated management programs. The spatial distribution of Meloidogyne javanica, Pratylenchus zeae, and mixed populations of P. zeae and P. brachyurus was studied in six commercial fields, with areas ranging from 0.26 to 0.50 ha; samples were obtained during the rainy season. The samples, represented by about 50 g roots, were collected within a rectangular grid measuring 7 × 12 m,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Saccharum; Meloidogyne; Pratylenchus; Spatial variability; Population. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162009000200007 |
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| Leal,Fábio Tiraboschi; França,Ana Beatriz Coelho; Siqueira,Diego Silva; Teixeira,Daniel De Bortoli; Marques Júnior,José; Scala Júnior,Newton La. |
| ABSTRACTSoil CO2 emissions (fCO2) in agricultural areas have been widely studied in global climate change research, but its characterization and quantification are restricted to small areas. Because spatial and time variability affect emissions, tools need to be developed to predict fCO2 for large areas. This study aimed to investigate soil magnetic susceptibility (MS) and its correlation with fCO2 in an agricultural environment. The experiment was carried out on a Typic Eutrudox located in Guariba-SP, Brazil. Results showed that there was negative spatial correlation between fCO2 and the magnetic susceptibility of Air Dried Soil (MSADS) up to 34.3 m distant. However, the fCO2 had no significant correlation with MSADS, magnetic susceptibility of sand... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Magnetism; Soil respiration; Spatial variability; Geostatistics. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162015000600535 |
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| Registros recuperados: 73 | |
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