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| Registros recuperados: 7.979 | |
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| Arcoverde,Sálvio N. S.; Souza,Cristiano M. A. de; Cortez,Jorge W.; Maciak,Paulo A. G.; Suárez,Andrés H. T.. |
| ABSTRACT Machine traffic and conventional tillage can cause structural degradation of the soil, affecting the physical attributes and, consequently, the production and longevity of the sugarcane field. The objective of this study was to evaluate the production components of sugarcane cultivars (RB965902, RB985476, RB966928, RB855156, RB975201, RB975242, RB036066 and RB855536) and physical attributes of a Dystroferric Red Latosol (Oxisol) under no-tillage and reduced-tillage systems. The experiment was conducted using a completely randomized experimental design in an 8 × 2 factorial arrangement, with four replicates. The soil attributes evaluated were density, total porosity, macroporosity, microporosity and penetration resistance. The production components... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Saccharum spp.; Plant cane; Soil management; Reduced-tillage; No-tillage. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000200216 |
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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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| Tavanti,Renan F. R.; Freddi,Onã da S.; Tavanti,Tauan R.; Rigotti,Adriel; Magalhães,Wellington de A.. |
| ABSTRACT The least limiting water range (LLWR) is a soil physical quality indicator that receives much attention. It has been criticized and put to the test regarding mathematical models that compose it since they describe the behavior of soil physical attributes in a simplified way. This study aimed to assess the efficiency of some pedofunctions proposed in the literature and artificial neural networks on the accuracy in predicting soil water retention at potentials equivalent to field capacity (θFC) and permanent wilting point (θPWP). In other words, to apply the best models to LLWR of two soil types (Oxisol and Ultisol) and verify changes in their structure. The results indicated that pedofunctions using sand, silt, clay, bulk density, and soil organic... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Soil physics; Soil physical quality indicator; Available water; Pedotransfer functions; Artificial neural networks. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000400444 |
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| Estevam,Francisca N. de L.; Queiroz,Renata F. de; Damasceno,André F.; Silva,Rouverson P. da; Voltarelli,Murilo A.; Barbosa Filho,José A. D.. |
| ABSTRACT Work in the field is characterized as unstructured because it is performed in inconvenient postures, without a fixed workstation, exposing the worker directly to the sun and other inclement weather. This may interfere in the health and the performance of the activity. The objective of this work was to characterize the environment of the agricultural microtractor operator, evaluating the thermal comfort during the activity in the municipality of Quixadá, CE. A model TC14 Super Yanmar Agritech microtractor, coupled to a rotary spindle, was used. For the measurements of the environmental variables, sensors and devices were installed on the operator and in the microtractor. The experimental design adopted the assumptions of statistical quality... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Operator health; Thermal load; Ergonomics. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000200208 |
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| Amaral,Lucas R. do; Justina,Diego D. Della. |
| ABSTRACT Data interpolation is widely required in precision agriculture. However, its effectiveness is a function of the characteristics of the dataset, being necessary for the evaluation of several parameters. This study aimed to identify how the spatial interpolators, Kriging, and Inverse Distance Weighting, are influenced by the degree of spatial dependence of the variables analyzed and the number of neighbors considered in the interpolation process (sampling neighborhood). Soil samples were collected from three sugarcane fields. By the optimization process, we verified that the sampling neighborhood influences the accuracy of interpolations, but there is not a standard recommendation to follow. Thus, the best sampling neighborhood must ever be... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Data interpolation; Soil sampling; Geostatistics; Site-specific management. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000800085 |
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| Cortez,Jorge W.; Syrio,Marina G.; Rodrigues,Sonia A.. |
| ABSTRACT Soybean has significant economic importance in Brazil despite high production costs, making it necessary to increase the efficiency of mechanized harvest through the reduction of losses. Thus, this study aimed to evaluate the total losses in the mechanized soybean harvest as a function of the combination of header types, operating speeds, and geometry of collection frames. The study was carried out in a commercial farm in a randomized block design arranged in a 2 × 3 × 3 factorial with 10 replications, totaling 180 replications. The data were analyzed by descriptive statistics, analysis of variance, and quality control. The square frame can be used instead of the rectangular frame for the determination of the total losses. The increasing operating... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Agricultural mechanization; Control charts; Glycine max. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000400482 |
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| Albiero,Daniel; Xavier,Reuel S.; Garcia,Angel P.; Marques,Arthur R.; Rodrigues,Ruan L.. |
| ABSTRACT Agricultural mechanization is a significant factor of agricultural modernization, but there are few data on the technological levels of this mechanization in the State of Ceará, Brazil. To study this topic, we designed a structured questionnaire, and interviews were conducted across the state. The survey data made it possible to calculate an index of agricultural mechanization technology and study hypotheses specific to farms of Ceará. The results indicate that the technology levels are different between farms of different sizes: large and medium farms are level I-M5 (automation), while small farms ranged from level IV-M1/M2 (primary/animal) to III-M3 (preliminary). We conclude that public policy for training should be directed at small farms.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Agricultural mechanization; Technological level; Technical efficiency; Economic development. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000100133 |
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| Carneiro,Franciele M.; Furlani,Carlos E. A.; Zerbato,Cristiano; Menezes,Patricia C. de; Gírio,Lucas A. da S.. |
| ABSTRACT Active optical sensors have been widely used for the spatial and temporal monitoring of peanut culture because they are accurate, non-destructive methods for rapidly obtaining data. The objective of this study was to determine the optimal stage of crop growth for collecting sensor readings based on correlations between quality indicators. In addition, we compared vegetation indices (Normalized Difference Vegetation Index [NDVI], Normalized Difference Red-Edge Index, [NDRE], and Inverse Ratio Vegetation Index, [IRVI]) by monitoring temporal variability in the peanut crop in order to determine which of them obtained the best reading quality throughout the process. The experiment was performed on the 2016/17 crop in the agricultural area of the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Remote sensing; Arachis hypogaea L.; Control charts; Precision agriculture. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000800033 |
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| Cortez,Jorge W.; Pusch,Maiara; Silva,Rouverson P. da; Rufino,Mauricio V.; Anghinoni,Matheus. |
| ABSTRACT The way the soil is managed can influence its structuring and, consequently, crop yield. Thus, this study aimed to evaluate the effect caused by the management systems plowing followed by two intermediate harrowing operations, intermediate harrowing, chiseling, chiseling followed by intermediate harrowing, cross chiseling followed by intermediate harrowing, and non-tillage on soil and agronomic attributes of the soybean crop. A randomized block design with four replications was used. The percentage of soil cover, soil resistance to penetration, number of plants per meter, longitudinal distribution of seedlings, and soybean yield were evaluated. The data were submitted to analysis of variance by the Tukey test at 5% probability, and use of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Resistance to penetration; Geostatistics; Soil tillage. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000400490 |
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| Christoforo,André L.; Almeida,Tiago H. de; Almeida,Diego H. de; Balanco,Giovana G.; Lahr,Francisco A. R.. |
| ABSTRACT Wood is one of the main materials used in the constructing of covering structures (roofs) because of its versatility. Under this situation, due to solar radiation incidence, the temperature can exceed 60 °C and, such as other environmental conditions, influence the mechanical properties of the wood in use. The aim of this research was to study the influence of exposure time of the wood of four different hardwood species at a temperature of 60 °C on the shear strength parallel to fibers. The wood of the following species was used: Cupiúba (Goupia glabra), Eucalyptus (Eucalyptus saligna), Garapeira (Apuleia leiocarpa), and Jatobá Tamarindo (Hymenaea sp.). In order to investigate the effect of exposure time (0, 168, 456, 720, and 2160 hours) of the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Hardwoods; Mechanical properties; Roofs; Temperature. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000300365 |
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| Salles,Josiane S.; Lima,Alexandre H. F. de; Costa,Edilson; Binotti,Eliana D. C.; Binotti,Flávio F. da S.. |
| ABSTRACT Papaya is characterized as one of the most important crops in Brazil. Thus, good quality seedlings are essential for formation of orchards in agricultural production. This study aimed to evaluate shading levels and substrate compositions for production of papaya seedlings. Growing environments were evaluated with 0, 18, 35, and 50% shading and substrates from combinations (%) of hillside soil (HS), cattle manure (CM), Bioplant® (BP), washed fine sand (FS), and super fine-grained vermiculite (FV). As there was no replication for the growing environments, the group of experiments were analyzed using a 4 × 4 factorial arrangement (4 shades × 4 substrates), with five replications. Growth and biometric relationships were analyzed. Substrates consisting... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Carica papaya L.; Plant ambience; Cattle manure; Vermiculite. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000600698 |
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| Cortez,Jorge W.; Silva,Rouverson P. da; Furlani,Carlos E. A.; Olszevski,Nelci; Nagahama,Hideo de J.. |
| ABSTRACT Fertilization systems that allow higher sowing speeds have been used in areas of grain production, as well as the use of intercropping to improve soil physical quality and provide better soil cover. This study aimed to evaluate soil attributes and the initial corn development and intercropping (corn + velvet bean, corn + pigeonpea, and corn + bonavist bean) as a function of fertilization systems (pre-sowing and sowing). The experiment was conducted in an Oxisol in a randomized block design in the 2 × 3 factorial scheme, with four replications. The number of days for emergence, plant stand, intercropping dry matter, soil straw cover, soil straw permanence index, penetration resistance, soil moisture, soil density, degree of compaction, and total... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Compaction; Vegetation cover; Soil physical quality. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000200257 |
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| Almeida Neto,Luiz A.; Pandorfi,Héliton; Moraes,Alex S.; Guiselini,Cristiane; C. Júnior,José J. Florentino. |
| ABSTRACT Sugarcane is considered one of the main alternatives for biofuel production and an important product of Brazilian agriculture, so it is indispensable to adopt new techniques for its cultivation and management. Thus, the present study aimed to evaluate the effect of the quality of supplemental lighting, based on light-emitting diode (LED), on the acclimation of pre-sprouted sugarcane seedlings in a protected environment. The experimental design was completely randomized, consisting of three supplemental LED lighting systems, with light proportions of 90% red + 10% blue (R:B 90/10), 80% red + 20% blue (R:B 80/20) and 70% red + 30% blue (R:B 70/30), and a control, with natural solar radiation, with 5 replicates. Multivariate principal component... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Principal components; Light-emitting diode; Supplemental lighting; Solar radiation. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000400410 |
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| Calou,Vinícius B. C.; Teixeira,Adunias dos S.; Moreira,Luis C. J.; Rocha Neto,Odílio C. da; Silva,José A. da. |
| ABSTRACT Unmanned aerial vehicles (UAVs) are a promising tool for technology development and transfer and for the economic success of the agricultural sector. The objective of this study is to assess the validity of biomass estimation in a commercial maize plantation using aerial images obtained by a UAV. The proposed methodology involved analyzing images acquired in scheduled flights, processing orthophoto (georeferenced image) data, evaluating digital terrain elevation models, and assessing the quality of dense point clouds. Data were collected using two cameras, one with a 16-megapixel flat lens and the other with a 12-megapixel fish-eye lens coupled to a UAV, at two flight altitudes (30 and 60 meters) over hybrid maize (AG1051) crop irrigated by center... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Precision agriculture; Structure from Motion; Unmanned aerial vehicles; Zea mays L. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000600744 |
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| Registros recuperados: 7.979 | |
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