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6 resultados encontrados para: AUTOR: Vaast, Philippe
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1.
Artículo
*Solicítelo con su bibliotecario/a
Native coffee agroforestry in the Western Ghats of India maintains higher carbon storage and tree diversity compared to exotic agroforestry
Guillemot, Joannès ; Le Maire, Guerric (coaut.) ; Munishamappa, Manjunatha (coaut.) ; Charbonnier, Fabien Sylvain Jacky (coaut.) ; Vaast, Philippe (coaut.) ;
Contenido en: Agriculture, Ecosystems and Environment Vol. 265 (October 2018), p. 461-469 ISSN: 0167-8809
Nota: Solicítelo con su bibliotecario/a
Resumen en: Inglés |
Resumen en inglés

The ongoing introduction of the exotic Grevillea robusta tree species into agroforestry systems (AFS) of the Indian Western Ghats could become a threat to both climate change mitigation and tree diversity conservation. Here, we quantified carbon (C) storage and shade tree diversity in native forests and coffee AFS under contrasted management (native versus exotic shade trees, Robusta versus Arabica systems) at 67 plots along a 3500mm precipitation gradient in the Cauvery watershed, India. Despite a substantial reduction of shade tree cover in native AFS compared to forest (from 90% to 32% in the high precipitation area), native AFS and forests displayed high and comparable C stocks (max. 228 MgC ha−¹ and 234 MgC ha-¹, respectively) and tree diversity (max. 44 and 45 species, respectively). Both variables were negatively impacted by the introduction of G. robusta, especially in Robusta coffee systems (max. 158 MgC ha−¹, 12 species). The current trend toward the introduction of G. robusta in coffee AFS of the study area (exotic agroforestry) negatively affects C storage and tree diversity, especially in Robusta coffee systems. Policy makers should take advantage of the carbon-tree diversity positive correlation found in the agroforestry landscape of the Western Ghats of India to promote conservation and climate change mitigation.


2.
- Artículo con arbitraje
Resumen en: Inglés |
Resumen en inglés

In agroforestry systems, shade trees strongly affect the physiology of the undergrown crop. However, a major paradigm is that the reduction in absorbed photosynthetically active radiation is, to a certain extent, compensated by an increase in light-use efficiency, thereby reducing the difference in net primary productivity between shaded and non-shaded plants. Due to the large spatial heterogeneity in agroforestry systems and the lack of appropriate tools, the combined effects of such variables have seldom been analysed, even though they may help understand physiological processes underlying yield dynamics. In this study, we monitored net primary productivity, during two years, on scales ranging from individual coffee plants to the entire plot. Absorbed radiation was mapped with a 3D model (MAESPA). Light-use efficiency and net assimilation rate were derived for each coffee plant individually. We found that although irradiance was reduced by 60% below crowns of shade trees, coffee light-use efficiency increased by 50%, leaving net primary productivity fairly stable across all shade levels. Variability of aboveground net primary productivity of coffee plants was caused primarily by the age of the plants and by intraspecific competition among them (drivers usually overlooked in the agroforestry literature) rather than by the presence of shade trees.


3.
Artículo
*En hemeroteca, SIBE-San Cristóbal
Coffee agroforestry systems in Central America: II. development of a simple process-based model and preliminary results
Van Oijen, Marcel ; Dauzat, Jean (coaut.) ; Harmand, Jean Michel (coaut.) ; Lawson, Gerry (coaut.) ; Vaast, Philippe (coaut.) ;
Contenido en: Agroforestry Systems Vol. 80, no. 3 (November 2010), p. 361-378 ISSN: 0167-4366
Bibliotecas: San Cristóbal
Cerrar
SIBE San Cristóbal
50034-10 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-San Cristóbal
Resumen en: Inglés |
Resumen en inglés

Research on coffee agroforestry systems in Central America has identified various environmental factors, management strategies and plant characteristics that affect growth, yield and the impact of the systems on the environment. Much of this literature is not quantitative, and it remains difficult to optimise growing area selection, shade tree use and management. To assist in this optimisation we developed a simple dynamic model of coffee agroforestry systems. The model includes the physiology of vegetative and reproductive growth of coffee plants, and its response to different growing conditions. This is integrated into a plot-scale model of coffee and shade tree growth which includes competition for light, water and nutrients and allows for management treatments such as spacing, thinning, pruning and fertilising. Because of the limited availability of quantitative information, model parameterisation remains fraught with uncertainty, but model behaviour seems consistent with observations. We show examples of how the model can be used to examine tradeoffs between increasing coffee and tree productivity, and between maximising productivity and limiting the impact of the system on the environment.


4.
Artículo
*En hemeroteca, SIBE-San Cristóbal
Coffee agroforestry systems in Central America: I. A review of quantitative information on physiological and ecological processes
Van Oijen, Marcel ; Dauzat, Jean (coaut.) ; Harmand, Jean Michel (coaut.) ; Lawson, H. M. (coaut.) ; Vaast, Philippe (coaut.) ;
Contenido en: Agroforestry Vol. 80, no. 3 (November 2010), p. 341-359 ISSN: 0167-4366
Bibliotecas: San Cristóbal
Cerrar
SIBE San Cristóbal
50033-10 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-San Cristóbal
Resumen en: Inglés |
Resumen en inglés

Coffee is widely grown across Central America at altitudes between 600 and 2500 m, mostly in association with trees that provide shade and other services. Research on coffee agroforestry systems has identified many environmental factors, management strategies and plant characteristics that affect growth, yield and environmental impact of the system. Much of this literature only presents qualitative estimates of the importance of the different growth determining factors, or highly site-specific estimates. Quantitative information is required to allow statistical analysis or the construction of process-based models of the system. Here, we review the available quantitative information for the latter purpose, with emphasis on the data needs for modelling agroforestry systems common in Central America. Process-based models require environmental data—weather, soil—and data on the physiological characteristics of the coffee plants and trees. Our review showed that the current literature is insufficient to allow full parameterisation of a process-based model for any coffee-tree combination. Information on weather, coffee and trees is highly limited, but soil information seems more adequate. A regional network of replicated multi-factorial experiments, focusing on the interactive effects of different environmental factors, may help address the main knowledge gaps.


5.
Artículo
*En hemeroteca, SIBE-San Cristóbal
Comportamiento fisiológico del café asociado con eucalyptus deglupta, terminalia ivorensis o sin sombra
Siles Gutiérrez, Pablo ; Vaast, Philippe (coaut.) ;
Contenido en: Agroforestería en las Americas Vol. 9, no. 35-36 (2002), p. 44-49 ISSN: 1022-7482
Bibliotecas: San Cristóbal
Cerrar
SIBE San Cristóbal
B8518 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-San Cristóbal
Resumen en: Español |
Resumen en español

El comportamiento fisiológico del café bajo Eucalyptus deglupta, Terminalia ivorensis y a pleno sol fue estudiado en las épocas seca y lluviosa en condiciones sub-óptimas en el sur de Costa Rica. La humedad del suelo en la época seca fue menor bajo T. ivorensis comparado con café bajo E. deglupta o a pleno sol, probablemente debido a una alta transpiración de T. ivorensis por sus mayores tasas de conductividad estomática en las horas del mediodía y de la tarde. La temperatura foliar del café fue generalmente superior a 27°C (por arriba del óptimo). En la mañana, la temperatura de las hojas del café bajo T. ivorensis fueron 4°C menores que a pleno sol, mientras que al mediodía esta diferencia fue de 2,4ºC (bajo E. deglupta las diferencias fueron de 1,9 y 1,5ºC). La tasa de asimilación neta de CO2 de hojas de café mostró un patrón similar a pleno sol y bajo E. deglupta, ya que las máximas tasas se observaron en la mañana y disminuyeron a lo largo del día. Al contrario bajo T. ivorensis, las mayores tasas de asimilación de café se alcanzaron en las horas del mediodía debido a una Radiación Fotosintéticamente Activa (RAFA) baja. La conductividad estomática de hojas de café fue mas alta bajo E. deglupta que bajo T. ivorensis debido a una mayor RAFA y fue también mas alta que a pleno sol debido a menores temperaturas foliares. Estos resultados respaldan la decisión empírica de los agricultores de la zona en preferir E. deglupta en comparación a T. ivorensis como árbol maderable de sombra para café.


6.
Artículo
*En hemeroteca, SIBE-San Cristóbal
Desarrollo del café asociado con eucalyptus deglupta o terminalia ivorensis en la etapa de establecimiento = Development of coffee associated with eucalyptus deglupta or terminalia ivorensis during the establishment phase
Aguilar, Amilcar ; Beer, John (coaut.) ; Vaast, Philippe (coaut.) ; Jiménez Otárola, Francisco (coaut.) ;
Contenido en: Agroforestería en las Américas Vol. 8, no. 30 (2001), p. 28-31 ISSN: 1022-7482
Bibliotecas: San Cristóbal
Cerrar
SIBE San Cristóbal
B7150 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-San Cristóbal