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A Crop Yield Expectation Stochastic Process with Beta Distribution as Limit AgEcon
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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Desarrollo floral del Cacto de Navidad (Schlumbergera truncata) y deshidratación de sus flores Colegio de Postgraduados
Martínez Aispuro, Ana Patricia.
Schlumbergera truncata (Worth) Moran, es una cactácea epífita originaria de Brazil, donde se le conoce como flor de Mayo y que debido a la belleza de su flor cigomorfa es ampliamente utilizada como planta ornamental de maceta en Estados Unidos de Norteamérica y de países de Europa y Asia, donde se le conoce como Cacto de Navidad. En México es poco conocida, pero se considera que tiene amplias perspectivas en la horticultura ornamental del país. Esta investigación tuvo los siguientes objetivos: 1) caracterizar el desarrollo de las yemas florales, 2) determinar la relación entre este desarrollo y la temperatura del aire, 3) deshidratar la flor con el objetivo de prolongar su uso ornamental conservando su forma y color entre otras características, y 4)...
Tipo: Tesis Palavras-chave: Schlumbergera truncata; Grados día de desarrollo; Deshidratación de la flor; Preservación de la flor; Schlumbergera truncata; Growing degree days; Flowers dehydration; Flowers preservation.
Ano: 2007 URL: http://hdl.handle.net/10521/1572
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Fenología, productividad de calidad de fruto con y sin semilla en Opuntia ficus-indica Colegio de Postgraduados
Hernández Ramírez, Carlos.
El nopal tunero es una alternativa productiva importante para las zonas áridas y semiáridas de México. La superficie de cultivo es de 53 212 ha bajo riego y temporal. Un problema que enfrenta el productor es la estacionalidad de la producción y la presencia de semillas en la pulpa. Investigadores mexicanos han obtenido logros importantes en la producción de tuna sin semilla en Opuntia ficus-índica cv. CP-Azteca de frutos con pulpa color rojo, que también se utilizó en esta investigación que comprende tres temas y que se presentan en tres capítulos. Los objetivos y resultados del trabajo fueron: I) Caracterizar en días y grados día acumulados los períodos desde la emergencia de yemas reproductivas a antesis y a maduración del fruto así como...
Tipo: Tesis Palavras-chave: Opuntia ficus-índica; Antesis; Grados día de desarrollo; Fruto partenocárpico; Radiación fotosintéticamente activa; Uso eficiente del agua; Doctorado; Fisiología Vegetal; Anthesis; Growing degree days; Parthenocarpic fruit; Photosynthetic active radiation; Water use efficiency..
Ano: 2009 URL: http://hdl.handle.net/10521/1371
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Fenología, productividad de calidad de fruto con y sin semilla en Opuntia ficus-indica Colegio de Postgraduados
Hernández Ramírez, Carlos.
El nopal tunero es una alternativa productiva importante para las zonas áridas y semiáridas de México. La superficie de cultivo es de 53 212 ha bajo riego y temporal. Un problema que enfrenta el productor es la estacionalidad de la producción y la presencia de semillas en la pulpa. Investigadores mexicanos han obtenido logros importantes en la producción de tuna sin semilla en Opuntia ficus-índica cv. CP-Azteca de frutos con pulpa color rojo, que también se utilizó en esta investigación que comprende tres temas y que se presentan en tres capítulos. Los objetivos y resultados del trabajo fueron: I) Caracterizar en días y grados día acumulados los períodos desde la emergencia de yemas reproductivas a antesis y a maduración del fruto así como...
Tipo: Tesis Palavras-chave: Opuntia ficus-índica; Antesis; Grados día de desarrollo; Fruto partenocárpico; Radiación fotosintéticamente activa; Uso eficiente del agua Opuntia ficus-indica; Anthesis; Growing degree days; Parthenocarpic fruit; Photosynthetic active radiation; Water use efficiency..
Ano: 2012 URL: http://hdl.handle.net/10521/1036
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Growth and development of Conyza bonariensis based on days or thermal units PAB
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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Growth and development of honey weed based on days or thermal units Planta Daninha
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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Growth and Development of Purple Nutsedge Based on Days or Thermal Units Planta Daninha
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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Growth and development of sourgrass based on days or thermal units Planta Daninha
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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Initial growth and development of southern sandbur based on thermal units Planta Daninha
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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Model of pre-harvest quality of pineapple guava fruits (Acca sellowiana (O. berg) burret) as a function of weather conditions of the crops Bragantia
Parra-Coronado,Alfonso; Fischer,Gerhard; Camacho-Tamayo,Jesús Hernán.
ABSTRACT Weather conditions influence the quality parameters of pineapple guava fruit during growth and development. The aim of this study was to propose a model of pre-harvest fruit quality as a function of weather conditions in the cultivation area. Twenty trees were flagged per farm in 2 localities of the Department of Cundinamarca, Colombia: Tenjo (2,580 m.a.s.l.; 12.5 °C; relative humidity between 74 and 86%; mean annual precipitation 765 mm) and San Francisco de Sales (1,800 m.a.s.l.; 20.6 °C; relative humidity between 63 and 97%; mean annual precipitation 1,493 mm). Measurements were performed every 7 days during 2 harvest periods starting on days 96 (Tenjo) and 99 (San Francisco de Sales) after anthesis and until harvest. The models were obtained...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Total soluble solids; Total titratable acidity; Firmness; Growing degree days.
Ano: 2017 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052017000100177
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Modeling Stochastic Crop Yield Expectations with a Limiting Beta Distribution AgEcon
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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Panicum maximum cv. Tanzânia: climate trends and regional pasture production in Brazil. Repositório Alice
PEZZOPANE, J. R. M.; SANTOS, P. M.; EVANGELISTA, S. R. M.; BOSI, C.; CAVALCANTE, A. C. R.; BETTIOL, G. M.; GOMIDE, C. A. de M.; PELLEGRINO, G. Q..
Projected change in forage production under a range of climate scenarios is important for the evaluation of the impacts of global climate change on pasture-based livestock production systems in Brazil. We evaluated the effects of regional climate trends on Panicum maximum cv. Tanzânia production, predicted by agro-meteorological model considering the sum of degree days and corrected by a water availa bility index. Data from Brazilian weather stations (1963?2009) were considered as the current climate (baseline), and future scenarios, based on contrasting scenarios interms of increased temperature and atmospheric CO2 concentrations (high and low increases), were determined for 2013?2040 (2025 scenario) and for 2043?2070 (2055 scenario). Predicted baseline...
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: ETA model; PRECIS model; Global climate changes; Growing degree days; Water balance; Planta forrageira; Water balance.
Ano: 2016 URL: http://www.alice.cnptia.embrapa.br/handle/doc/1055482
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Pólya’s Urn Model for Crop Yield Expectation Stochastic Process AgEcon
Hennessy, David A..
Tipo: Conference Paper or Presentation Palavras-chave: Crop insurance; Growing degree days; Martingale; Pólya urn; Stochastic process.; Crop Production/Industries; Financial Economics; Production Economics.
Ano: 2010 URL: http://purl.umn.edu/60896
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Sources de variation de la forme des otolithes: Implications pour la discrimination des stocks de poissons ArchiMer
Mahe, Kelig.
The assessment and management of fish populations is based on the use of management units called fish stocks. The shape of otoliths, calcified structures of the fish's inner ear, can be used to discriminate these stocks. First, this thesis focuses on the study of the spatio-temporal variability of the otolith’s shape for three fish species with different ecological characteristics (size, swimming speed, behaviour in the water column, etc.) and biogeographical environments. The results showed that there is a decreasing structural gradient across stock sizes from large pelagic species to more localised demersal species. This is linked to the fact that some demersal species such as the bogue (Boops boops) are constrained by the presence of geographical...
Tipo: Text Palavras-chave: Otolithe; Forme; Stock halieutique; Descripteurs de Fourier; Température; Acides gras; Asymétrie directionnelle; Degrés-jours de croissance; Otolith; Shape; Fish stock; Fourier descriptors; Temperature; Fatty acids; Directional asymmetry; Growing degree days.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00598/70972/69201.pdf
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