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| Registros recuperados: 223 | |
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| Pezzopane,José Ricardo Macedo; Santos,Patricia Menezes; Mendonça,Fernando Campos; Araujo,Leandro Coelho de; Cruz,Pedro Gomes da. |
| The objective of this work was to develop and validate linear regression models to estimate the production of dry matter by Tanzania grass (Megathyrsus maximus, cultivar Tanzania) as a function of agrometeorological variables. For this purpose, data on the growth of this forage grass from 2000 to 2005, under dry‑field conditions in São Carlos, SP, Brazil, were correlated to the following climatic parameters: minimum and mean temperatures, degree‑days, and potential and actual evapotranspiration. Simple linear regressions were performed between agrometeorological variables (independent) and the dry matter accumulation rate (dependent). The estimates were validated with independent data obtained in São Carlos and Piracicaba, SP, Brazil. The best statistical... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Panicum maximum; Climatic growth index; Degree‑days; Evapotranspiration; Modeling. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2012000400001 |
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| Ferraz,Patricia Ferreira Ponciano; Yanagi Junior,Tadayuki; Hernández Julio,Yamid Fabián; Castro,Jaqueline de Oliveira; Gates,Richard Stephen; Reis,Gregory Murad; Campos,Alessandro Torres. |
| The objective of this work was to develop, validate, and compare 190 artificial intelligence-based models for predicting the body mass of chicks from 2 to 21 days of age subjected to different duration and intensities of thermal challenge. The experiment was conducted inside four climate-controlled wind tunnels using 210 chicks. A database containing 840 datasets (from 2 to 21-day-old chicks) - with the variables dry-bulb air temperature, duration of thermal stress (days), chick age (days), and the daily body mass of chicks - was used for network training, validation, and tests of models based on artificial neural networks (ANNs) and neuro-fuzzy networks (NFNs). The ANNs were most accurate in predicting the body mass of chicks from 2 to 21 days of age... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Animal welfare; Artificial neural network; Broiler; Modeling; Neuro-fuzzy network; Thermal comfort. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2014000700559 |
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| Aparecido,Lucas Eduardo de Oliveira; Batista,Rafael Madureira; Moraes,José Reinaldo da Silva Cabral de; Costa,Cícero Teixeira Silva; Moraes-Oliveira,Adriana Ferreira de. |
| Abstract: The objective of this work was to elaborate the agricultural zoning of climatic risk (ZARC) for Physalis peruviana, through the thermal and water requirements of the crop in Southeastern Brazil. Air temperature (TAIR) and precipitation (PYEAR) data from 1,530 meteorological stations covering the entire region were used. Regions were considered climatically favorable to Physalis peruviana when TAIR was between 13 and 18ºC and PYEAR between 1,000 and 2,000 mm per year. Regions where TAIR was above 30ºC or less than 13ºC were considered inapt. Maps were created with this information and used to identify climatic characteristics and to establish the agricultural aptitude classes, termed apt, inapt, and marginal for the cultivation of Physalis... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Climate risk; Agrometeorology; Modeling; Big data. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2019000100900 |
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| Soares,Daniel Jorge; Oliveira,Wladecir Salles de; Uzuele,Elvio Lorençato; Carvalho,Saul Jorge Pinto de; Ovejero,Ramiro Fernando Lopez; Christoffoleti,Pedro Jacob. |
| Abstract: The objective of this work was to evaluate the growth and development of a glyphosate-resistant population of Conyza bonariensis in different sowing dates (autumn, winter, and spring) and in two agricultural environments, based on days or thermal units. Five experiments were performed in two agricultural environments in Brazil: two in the municipality of Não-Me-Toque, in the state of Rio Grande do Sul - with sowings in July and September 2011; and three in the municipality of Santa Cruz das Palmeiras, in the state of São Paulo ‒ with sowings in April, July, and September 2011. In each trial, ten evaluations of the phenological development and total dry mass of C.bonariensis were performed, fitting these variables to a unit of time in days or... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Hairy fleabane; Dry mass; Growing degree days; Modeling; Phenology; Weed biology.. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2017000100045 |
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| Cargnelutti Filho,Alberto; Toebe,Marcos. |
| Abstract: The objective of this work was to determine the number of plants required to model corn grain yield (Y) as a function of ear length (X1) and ear diameter (X2), using the multiple regression model Y = β0 + β1X1 + β2X2. The Y, X1, and X2 traits were measured in 361, 373, and 416 plants, respectively, of single-, three-way, and double-cross hybrids in the 2008/2009 crop year; and in 1,777, 1,693, and 1,720 plants, respectively, of single-, three-way, and double-cross hybrids in the 2009/2010 crop year, totaling 6,340 plants. Descriptive statistics were calculated, and frequency histograms and scatterplots were created. The sample size (number of plants) for the estimate of the β0, β1, and β2 parameters, of the residual standard error, the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Zea mays; Descriptive statistics; Hybrids; Modeling; Resampling. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2020000102100 |
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| Lima,R.S.O.; Machado,E.C.R.; Silva,A.P.P.; Marques,B.S.; Gonçalves,M.F.; Carvalho,S.J.P.. |
| This work was carried out with the objective of elaborating mathematical models to predict growth and development of purple nutsedge (Cyperus rotundus) based on days or accumulated thermal units (growing degree days). Thus, two independent trials were developed, the first with a decreasing photoperiod (March to July) and the second with an increasing photoperiod (August to November). In each trial, ten assessments of plant growth and development were performed, quantifying total dry matter and the species phenology. After that, phenology was fit to first degree equations, considering individual trials or their grouping. In the same way, the total dry matter was fit to logistic-type models. In all regressions four temporal scales possibilities were assessed... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cyperus rotundus; Growing degree days; Phenology; Base temperature; Modeling. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582015000200165 |
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| Machado,E.C.R.; Lima,R.S.O.; Silva,A.P.P.; Marques,B.S.; Gonçalves,M.F.; Carvalho,S.J.P.. |
| Availability of basic information on weed biology is an essential tool for designing integrated management programs for agricultural systems. Thus, this study was carried out in order to calculate the base temperature (Tb) of southern sandbur (Cenchrus echinatus), as well as fit the initial growth and development of the species to accumulated thermal units (growing degree days - GDD). For that purpose, experimental populations were sown six times in summer/autumn conditions (decreasing photoperiod) and six times in winter/spring condition (increasing photoperiod). Southern sandbur phenological evaluations were carried out, on alternate days, and total dry matter was measured when plants reached the flowering stage. All the growth and development fits were... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cenchrus echinatus; Weed; Biology; Growing degree days; Modeling. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582014000200011 |
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| Laajimi, Abderraouf; Guesmi, Anis; Mahfoudhi, A.; Dhehibi, Boubaker. |
| In Tunisia, peaches have a significant place in the fruit tree sector. Planted areas have been expanding ever since the eighties as a result of irrigation water extension and the use of better yielding varieties. These factors resulted in high production levels and fruit exports thereof. However, important seasonal and annual variation of fruit supplies continues to characterize prices at both wholesale and consumption levels. To study the response of peach production an econometric model was developed. Modelling was carried out in two stages. First area variation was explained through new plantings and removals and second yield variation was analyzed. The methodological approach followed takes into account the characteristics and... |
| Tipo: Journal Article |
Palavras-chave: Supply response; Modeling; Price expectations; Peaches; Demand and Price Analysis. |
| Ano: 2009 |
URL: http://purl.umn.edu/93801 |
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| Kanwar, Ramesh S.; Reungsang, Pipat; Jha, Manoj K.; Gassman, Philip W.; Ahmad, Khalil; Saleh, Ali. |
| A validation study has been performed using the Soil and Water Assessment Tool (SWAT) model with data collected for the Upper Maquoketa River Watershed (UMRW), which drains over 16,000 ha in northeast Iowa. This validation assessment builds on a previous study with nested modeling for the UMRW that required both the Agricultural Policy EXtender (APEX) model and SWAT. In the nested modeling approach, edge-of-field flows and pollutant load estimates were generated for manure application fields with APEX and were then subsequently routed to the watershed outlet in SWAT, along with flows and pollutant loadings estimated for the rest of the watershed routed to the watershed outlet. In the current study, the entire UMRW cropland area was simulated in SWAT, which... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Calibration; Modeling; Nitrate; SWAT; Validation; Water quality; Resource /Energy Economics and Policy. |
| Ano: 2005 |
URL: http://purl.umn.edu/18440 |
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| Olubode-Awosola, Femi. |
| As New Zealand farming industry pursues more productivity this has implication for environment and makes land use and agricultural policy decision processes more complex for which integrated assessment modeling (IAM) can support. The purpose of this review paper is to propose means through which IAM can be improved specifically to minimize uncertainties and increase relevance, reliability, and utility of outputs of different models. Literature suggests that the general motivation for land use change is that farmers do consider the environment, but need to maintain profitability. There are handful decision support tools for land use and land policy decisions but one common feature of most of the models is that each seems suitable for only a part of the... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Integrated assessment; Modeling; Complexity; Farming industry; New Zealand; Agribusiness; Land Economics/Use. |
| Ano: 2011 |
URL: http://purl.umn.edu/115404 |
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| Registros recuperados: 223 | |
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