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| Registros recuperados: 13 | |
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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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| Marques,B.S.; Silva,A.P.P.; Lima,R.S.O.; Machado,E.C.R.; Gonçalves,M.F.; Carvalho,S.J.P.. |
| This work was carried out with the objective of evaluating growth and development of sourgrass (Digitaris insularis) based on days or thermal units (growing degree days - GDD). Two independent trials were developed aiming to quantify the species' phenological development and total dry matter accumulation in increasing or decreasing photoperiod conditions. Plants were grown in 4 L plastic pots, filled with commercial substrate, adequately fertilized. In each trial, nine growth evaluations were carried out, with three replicates. Phenological development of sourgrass was correctly fit to time scale in days or GDD, through linear equation of first degree. Sourgrass has slow initial growth, followed by exponential dry matter accumulation, in increasing... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Digitaria insularis; Growing degree days; Phenology; Dry matter; Biology. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582014000300003 |
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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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| Silva,A.P.P.; Marques,B.S.; Lima,R.S.O.; Machado,E.C.R.; Gonçalves,M.F.; Carvalho,S.J.P.. |
| This work was carried out with the objective of evaluating the growth and development of honey weed (Leonurus sibiricus) based on days or thermal units (growing degree days). Thus, two independent trials were developed to quantify the phenological development and total dry mass accumulation in increasing or decreasing photoperiod conditions. Considering only one growing season, honey weed phenological development was perfectly fit to day scale or growing degree days, but with no equivalence between seasons, with the plants developing faster at increasing photoperiods, and flowering 100 days after seeding. Even day-time scale or thermal units were not able to estimate general honey weed phenology during the different seasons of the year. In any growing... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Leonurus sibiricus; Growing degree days; Phenology; Dry mass; Biology. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582014000100009 |
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| Hennessy, David A.. |
| The modeling of price risk in the theory and practice of commodity risk management has been developed far beyond that of crop yield risk. This is in large part due to the use of plausible stochastic price processes. We use the Pólya urn to identify and develop a model of the crop yield expectation stochastic process over a growing season. The process allows a role for agronomic events, such as growing degree days. The model is internally consistent in adhering to the martingale property. The limiting distribution is the beta, commonly used in yield modeling. By applying binomial tree analysis, we show how to use the framework to study hedging decisions and crop valuation. |
| Tipo: Working or Discussion Paper |
Palavras-chave: Crop insurance; Growing degree days; Martingale; Pólya urn; Stochastic process.; Risk and Uncertainty. |
| Ano: 2009 |
URL: http://purl.umn.edu/54829 |
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| Hennessy, David A.. |
| The use of plausible stochastic price processes in price risk analysis has allowed advances not seen in crop yield risk analysis. This study develops a stochastic process for yield modeling and risk management. The Pólya urn process is an internally consistent dynamic representation of yield expectations over a growing season that accommodates agronomic events such as growing degree days. The limiting distribution is the commonly used beta distribution. Binomial tree analysis of the process allows us to explore hedging decisions and crop valuation. The method is empirically flexible to accommodate alternative assumptions on the growing environment, such as intra-season input decisions. |
| Tipo: Journal Article |
Palavras-chave: Crop abandonment; Crop insurance; Derivative analysis; Growing degree days; Pólya’s urn; Stochastic process; Crop Production/Industries. |
| Ano: 2011 |
URL: http://purl.umn.edu/105548 |
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| Registros recuperados: 13 | |
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