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| Registros recuperados: 10 | |
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| Guedes Filho,Osvaldo; Vieira,Sidney Rosa; Chiba,Marcio Koiti; Grego,Célia Regina. |
| It is known, for a long time, that crop yields are not uniform at the field. In some places, it is possible to distinguish sites with both low and high yields even within the same area. This work aimed to evaluate the spatial and temporal variability of some crop yields and to identify potential zones for site specific management in an area under no-tillage system for 23 years. Data were analyzed from a 3.42 ha long term experimental area at the Centro Experimental Central of the Instituto Agronômico, located in Campinas, Sao Paulo State, Brazil. The crop yield data evaluated included the following crops: soybean, maize, lablab and triticale, and all of them were cultivated since 1985 and sampled at a regular grid of 302 points. Data were normalized and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Spatial variability; Cross semivariogram; Management zones. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052010000500003 |
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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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| Cagna,Camila P.; Calábria,Zieglenristen K. P.; Guedes Filho,Osvaldo; Pacheco,Leandro P.; Silva,Tonny J. A. da. |
| ABSTRACT Integration of forage grasses with grain crops, such as maize, allows maintaining soil cover. The objective of this study was to evaluate the tensile strength, friability, and stability of soil aggregates in the maize and forage grass intercropping under no-tillage system. The study used a completely randomized block design with seven treatments and three replications. Undisturbed soil samples were collected in two seasons (2015 and 2016) at 0–0.10 m and 0.10–0.20 m soil depth. The following properties of soil aggregates were measured: tensile strength (TS), friability (F), gravimetric moisture (GM), weighted mean diameter (WMD), geometric mean diameter (GMD), and aggregate stability index (ASI). The intercropping of maize with Urochloa... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aggregate stability index; Tensile strength; Soil physical quality. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000400512 |
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| Silva,Raimunda Alves; Siqueira,Glécio Machado; Costa,Mayanna Karlla Lima; Guedes Filho,Osvaldo; Silva,Ênio Farias de França e. |
| 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 traps were maintained for seven days. After this period, they were removed and their content transferred to bottles and taken to the laboratory, where the insects were screened and identified at the level of orders and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Soil biodiversity; Soil properties; Geostatistics. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832018000100409 |
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| Vieira,Sidney Rosa; Guedes Filho,Osvaldo; Chiba,Márcio Koiti; Mellis,Estevão Vicari; Dechen,Sônia Carmela Falci; De Maria,Isabella Clerici. |
| A análise dos teores de nutrientes de folhas de soja é um dos métodos mais eficientes para avaliar o estado nutricional da lavoura. O objetivo deste estudo foi caracterizar a variabilidade espacial dos teores foliares de nutrientes e da produtividade da cultura da soja num Latossolo Vermelho sob sistema semeadura direta durante dois anos. A área do experimento media 120 x 160 m, totalizando 1,92 ha. As amostras de folhas e os dados de produtividade da soja foram coletados em grade regular de 20 m, totalizando 63 pontos de amostragem nos anos de 1986 e 1988. O teor de nutrientes (N, P, K, Ca, Mg, S, B, Cu, Fe, Mn e Zn) foi determinado analisando-se a terceira folha com pecíolo a partir do ápice de cinco plantas, em locais circunvizinhos de cada um dos... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Diagnose foliar; Geoestatística; Sistema plantio direto. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832010000500003 |
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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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| Blum,Julius; Giarola,Neyde Fabíola Balarezo; Silva,Álvaro Pires da; Guedes Filho,Osvaldo; Silva,Sâmala Glícia Carneiro; Eberhardt,Diogo Néia; Araújo,Suzana Romeiro. |
| In no-till systems, two different soil conditions are created during the sowing operation: row and inter-row positions. The objectives of this study were to evaluate, using static and dynamic soil attributes, the influence of no-till sowing operation on creating better physical environment for soybean crop growth. A field transect with clay content ranging from 150 to 400 g kg-1 was selected in Ponta Grossa, Paraná State, Brazil, from a Typic Hapludox that has been cultivated under no-till system for 16 years. After soybean harvest, 68 undisturbed soil samples were collected at both sowing row and inter-row positions. The following soil properties were evaluated: saturated hydraulic conductivity, air permeability, bulk density, total porosity, soil... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Soil physical quality; Soil conservation tillage; Soil compaction; Air permeability; Saturated hydraulic conductivity. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902014000500004 |
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| Registros recuperados: 10 | |
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