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| Registros recuperados: 152 | |
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| Maia,Celsemy E.; Morais,Elis R. C. de. |
| ABSTRACTThis study aimed to estimate the critical levels for soil chemical attributes through the criterion of reduced continuous probability distribution (NCRIz) in areas under irrigated banana cultivation and evaluate soil fertility of low-yield areas in the Apodi Plateau. A dataset composed of analysis of 60 producing areas and their respective yields was used. It was concluded that the method can be used to obtain critical levels for soil chemical attributes and the critical levels obtained for the irrigated areas under banana cultivation corresponded to 7.2 for pH, 0.91 g kg-1 for N, 0.31, 6.34, 2.63, 1.42 and 25.76 mg kg-1 for Cu, Fe, Mn, Zn and P, respectively, and 6.43, 1.14, 0.24 and 0.36 cmolc kg-1 for Ca, Mg, Na and K, respectively. In the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Soil fertility; Modelling; Musa spp.. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662015001000926 |
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| Morais,José E. F. de; Silva,Thieres G. F. da; Queiroz,Maria G. de; Araújo,Gherman G. L. de; Moura,Magna S. B.; Araújo Júnior,George do N.. |
| ABSTRACT The knowledge on soil water dynamics is the basis of crop water management. The soil water balance (SWB) method is used for this purpose. However, its application in cactus may lead to misinterpretation in water efficiency analysis, since it does not consider the amount of water retained in the plant (WRP). This study aimed to evaluate SWB applicability, hydrodynamic changes and water efficiency of forage cactus clones under irrigation. The clones ‘Orelha de Elefante Mexicana’ (OEM), ‘IPA Sertânia’ (IPA) and ‘Miúda’ (MIU) were submitted to irrigation depths (2.5, 5.0 and 7.5 mm) and frequencies (7, 14 and 28 days), in Serra Talhada, PE, Brazil, between March 2012 and August 2013. The SWB was applied, by adding the WRP in the estimate of the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Water retained in the plant; Soil water balance; Cactus; Modelling. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662017000400273 |
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| Dalmago,Genei Antonio; Bianchi,Cleusa Adriane Menegassi; Kovaleski,Samuel; Fochesatto,Elizandro. |
| ABSTRACT The aim of this study was to evaluate estimations of leaf area in rapeseed (Brassica napus L.) and the potential for application to different genotypes, environmental conditions and types of crop management. In experiments conducted during 2013, 2014, 2016 and 2017, three genotypes of rapeseed, five doses of nitrogen and three sowing dates were used. Leaves were randomly collected from different plants and positions on the plants. The leaf area (LA), and maximum width (W) and length (L) were determined for each leaf, and the product of L and W (LxW) was calculated. Fifty-six equations for estimating LA in rapeseed, where the independent variables were W, L or LxW, were compiled from the bibliography and evaluated in this work. The evaluation was... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Brassica napus; Colza; Modelling; Leaf area index. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902019000300420 |
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| Lucas,Dioneia Daiane Pitol; Heldwein,Arno Bernardo; Hinnah,Fernando Dill; Maldaner,Ivan Carlos; Loose,Luis Henrique. |
| The aim of this study was to obtain a mathematical model for estimating the leaf area index (LAI) of a sunflower crop as a function of accumulated thermal time. Generating the models and testing their coefficients was carried out using data obtained from experiments carried out for different sowing dates in the crop years of 2007/08, 2008/09, 2009/10 and 2010/11 with two sunflower hybrids, Aguará 03 and Hélio 358. Linear leaf dimensions were used for the non-destructive measurement of the leaf area, and thermal time was used to quantify the biological time. With the data for accumulated thermal time (TTa) and LAI known for any one day after emergence, mathematical models were generated for estimating the LAI. The following models were obtained, as they... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Helianthus annuus; Leaf analysis; Modelling. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902015000200404 |
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| Perondi,Dani; Kipper,Marcos; Andretta,Ines; Hauschild,Luciano; Lunedo,Raquel; Franceschina,Carolina Schell; Remus,Aline. |
| ABSTRACT Several empirical models were proposed to predict feed intake (FI) of growingfinishing pigs reared under high environmental temperatures. However, these models have not been evaluated under conditions different from those in which they were developed. Twelve empirical models were evaluated using a database built after systematic literature review (observed data: 28 studies in which the FI was evaluated in pigs under high environmental temperatures). Model accuracy was assessed using the mean squared of prediction error (MSPE). Analyses were performed considering two scenarios: (1) general population, where all observed data were used in the simulation; (2) reference population, where data were filtered in order to simulate only scenarios with... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Consumption; Heat stress; Modelling; Precision feeding; Swine. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162018000400296 |
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| Andretta,Ines; Kipper,Marcos; Hauschild,Luciano; Lehnen,Cheila Roberta; Remus,Aline; Melchior,Raquel. |
| ABSTRACT Little is known about the toxicity of concomitantly occurring mycotoxins in pig diets. This study was conducted to evaluate, through meta-analysis, the individual and the combined effects of mycotoxins on pig performance. The meta-analysis followed three sequential analyses (graphical, correlation, and variance-covariance) based on a database composed of 85 published papers, 1,012 treatments and 13,196 animals. Contamination of diets with individual mycotoxins reduced (p < 0.05) feed intake by 14 % and weight gain by 17 %, while combined mycotoxins reduced the same responses by 42 % and 45 %, respectively, in comparison with the non-challenged group. The correlation (p < 0.05) between reduction in weight gain (ΔG) and reduction in feed... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Modelling; Sanitary challenge; Swine; Toxicology. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162016000400328 |
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| Lucena, Leandro Ricardo Rodrigues de; Holanda, Marco Aurélio Carneiro de; Holanda, Mônica Calixto Ribeiro de; Anjos, Marcelo Lopes dos. |
| This study adjusted different regression models to describe the growth pattern of meat quails from birth to 42 days of age. Data of 300 male quails were used. Weight and height information of all quails were collected weekly from the 1st to the 42nd day of age. Body weight of poultry was subjected to the polynomial, logistic, Gompertz, Weibull, and log-normal regression models. The criteria used to choose the best model to explain the growth curve of quails were the coefficient of determination of the model, Akaike’s information criterion, sum of squared residuals and Willmott’s index. For all the models used, the variables age and height were significant to explain the weight of quails. The polynomial (R² = 99.99%, AIC = 24.68, SSR = 27.5, d = 0.9999) and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Modelling; Poultry; Regression model.. |
| Ano: 2018 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAnimSci/article/view/42563 |
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| Odey, Simon Ogbeche. |
| Abstract: Field experiment was conducted at the teaching and research farm of Cross River University of Technology, Faculty of Agriculture and Forestry, Obubra Campus. The study was aimed at finite modelling of growth and yield of Okra (Abelmoschus esculentus L.) using different tillage systems. Randomised Complete Block Design (RCBD) was used in the field, 1,024m2 with three treatments and three replicates. These treatments were Conventional, Conservative and Zero tillage. Each treatment had three replicates of size 8m x 8m, separated from each other by 2m for manoeuvring of the tractor. Planting of okra and other cultural practices were carried out. Soil samples were collected for analysis in the laboratory. Data on growth parameters and yield of okra... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Finite; Modelling; Growth; Yield; Okra; Tillage Systems; Soil. |
| Ano: 2022 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/7067 |
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| Nkakini, Silas Ovua; Douglas, I. E.. |
| In this study, a comparative evaluation of tractive force models for disc harrowing, at different tillage speeds was carried out in order to determine optimal tillage speeds. The predictive models were developed using dimensional analysis. The tillage operation in a loamy sand soil, at tillage speeds of 1.94 m s-1, 2.22 m s-1 and 2.5 m s-1 respectively was conducted, using trace tractor techniques. Parameters such as drawbar pull, rolling resistance, wheel slip, moisture content, cone index, wheel numeric, contact pressure, speed, width of harrow, depth of harrow, and tractive force were measured. The developed mathematical models describing the tractors tyre-soil interactions parameters were evaluated using sensitivity analysis of the measured... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Predictive; Tractive force; Disc harrowing; Tillage; Loamy; Sand; Soil; Modelling; Sensitivity measurement; Soil moisture.. |
| Ano: 2013 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/2374 |
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| Arcidiacono, Claudia. |
| Heat stress in animal housing is one of the drivers affecting animal productivity and welfare in hot climates, and causing consequent reduced profits for the farmers. The main challenges that livestock breeding faces in hot climates regards how to foster, improve, and assess methods and strategies for animal heat stress abatement. Research studies in this field have generally proposed modifications in herd management and in feeding strategies, breed selection, and engineered solutions aimed at exploiting heat transmission phenomena. In this paper, the most recent engineered solutions for animal heat stress abatement in livestock buildings have been reviewed and described; they have involved new building and ventilation design and modelling, and improved... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Rural buildings livestock buildings; Design; Modelling; Ventilation; Hot climate. |
| Ano: 2018 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/4705 |
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| SANUSI, Mayowa Saheed; Akinoso, Rahman. |
| This study was designed to evaluate and model the impacts of processing parameters (steaming time, soaking time, paddy moisture content and soaking temperature) on the energy consumption of five rice varieties (NERICA 8, FARO 52, FARO 61, FARO 60 and FARO 44). Energy consumption in the cleaning, soaking, steaming, drying, dehusking, polishing and grading operations were estimated by fitting data on labour, fuel and electricity consumption, time and machine efficiency into standard equations to determine total energy consumption. The energy consumptions were separately modelled using Taguchi and Artificial Neural Network (ANN) techniques for each rice variety. The accuracy of models was determined using the coefficient of determination (R2) and Mean Square... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Artificial neural network; Energy Consumption; Modelling; Rice varieties; Taguchi. |
| Ano: 2022 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/7235 |
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| Sven Nimmermark. |
| In regions with a colder climate the use of heat energy for climatization of greenhouses can be significant. Beside outdoor temperatures and climate also transpiration affects the use of heat energy since heating and ventilation or dehumidification may be required in order to keep the humidity in the greenhouse below levels which may lead to plant diseases. A reliable model is a powerful tool to predict energy use for greenhouse cultivation. Thus, a mechanistic model including transpiration and energy use for dehumidification and hourly output data was developed from an older simpler model. To be reliable, modelled data must fit with real data. The aim of the present study is to compare measured and modelled use of heat energy. Thus, energy use for a... |
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Palavras-chave: Greenhouses; Energy; Measurements; Modelling. |
| Ano: 2015 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/3100 |
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| Ishpekov, Stoyan Savov. |
| The investigation aims at modelling the dynamics of rotational vibration generator, which is widely used for driving flow fruit detachers at harvesting of many crops like grape, tomatoes, blueberries, raspberries, chokeberry, black currant, sesame seeds etc. The research on this model has been digitally performed by software, written in FORTRAN and by using the LabView environment as input-output interface. Identification of unknown model coefficients has been carried and their influence upon precision of the model has been determined. The effect of vibration generator parameters upon its dynamic characteristics has been defined. The synthesized model reaches a relative error for the carrier angular amplitude of 0.48 % compared to the one, determined by an... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Agricultural engineering flow fruit detacher; Rotation vibration generator; Modelling. |
| Ano: 2018 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/3940 |
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| Almaliki, Salim; Alimardani, Reza; Omid, Mahmoud. |
| Due to the ascending importance of energy in the world, prediction and optimization of Fuel Consumption (FC) in agricultural tasks is merit to consideration. In this study a Massey Ferguson (MF285) tractor was implemented with a low cost and precise data acquisition system as a means to record and monitor the affectual parameters on FC such as forward speed and instant fuel flow rate during field operation. Field experiments were carried out in the experimental farm of Agricultural Engineering Department of Tehran University, Karaj province, Iran, which had loamy soil texture. A mouldboard plow was used as tillage toll during the experiments at various tillage depths, engine speeds, forward speeds, tire inflation pressures, moisture contents and cone... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Fuel consumption; Massey Ferguson (MF285); Modelling; Data logging system. |
| Ano: 2016 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/3776 |
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| Registros recuperados: 152 | |
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