The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform

Aguilar A Carrillo - One of the best experts on this subject based on the ideXlab platform.

  • soil erosion and erosion thresholds in an agroforestry system of coffee coffea arabica and mixed Shade Trees inga spp and musa spp in northern nicaragua
    Agriculture Ecosystems & Environment, 2015
    Co-Authors: Blanco R Sepulveda, Aguilar A Carrillo
    Abstract:

    Abstract Soil erosion by water is one of the main environmental problems in tropical mountain regions of Central America. Agroforestry systems have been shown to reduce erosion through their canopy cover and their contribution to the litter layer. This paper analyzes the influence of the cover and height of coffee strata and mixed Shade Trees, the ground cover (weeds and litter), the slope gradient and various soil features and characteristics relevant to erosion in six farms that apply the agroforestry system of coffee growing (Coffea arabica) with mixed Shade Trees of Musa spp and Inga spp. We determine the corresponding erosion thresholds, i.e. the value (erodibility factor) beyond which the reduction in erosion becomes statistically significant. A purpose-designed verification method was applied to determine whether the thresholds corresponded to the effective control of erosion. The study area is located in the hills around El Cua, in northern Nicaragua, an area with a humid tropical climate and a mean annual rainfall of 2770 mm. An analytical method, based on the use of visual indicators, was used to analyze soil erosion by water. This approach enabled us to replicate the method in a sufficiently large number of cases for the results obtained to be considered reliable and representative of the study area. These results indicate that in the agroforestry system examined, for the cultivation of coffee and mixed Shade Trees (Musa spp and Inga spp), an average of 10.4% of the area is affected by erosion. The erodibility factors identified were litter layer and slope gradient. The first of these factors accounted for 66% of the variability of erosion, compared with 4% in the second case. The erosion threshold value was between 60 and 65% of the litter layer; beyond this level, the reduction in erosion was statistically significant. With this threshold, the soil was relatively little affected by erosion, around 13% of the cultivated area.

  • soil erosion and erosion thresholds in an agroforestry system of coffee coffea arabica and mixed Shade Trees inga spp and musa spp in northern nicaragua
    Agriculture Ecosystems & Environment, 2015
    Co-Authors: Blanco R Sepulveda, Aguilar A Carrillo
    Abstract:

    Abstract Soil erosion by water is one of the main environmental problems in tropical mountain regions of Central America. Agroforestry systems have been shown to reduce erosion through their canopy cover and their contribution to the litter layer. This paper analyzes the influence of the cover and height of coffee strata and mixed Shade Trees, the ground cover (weeds and litter), the slope gradient and various soil features and characteristics relevant to erosion in six farms that apply the agroforestry system of coffee growing ( Coffea arabica ) with mixed Shade Trees of Musa spp and Inga spp . We determine the corresponding erosion thresholds, i.e. the value (erodibility factor) beyond which the reduction in erosion becomes statistically significant. A purpose-designed verification method was applied to determine whether the thresholds corresponded to the effective control of erosion. The study area is located in the hills around El Cua, in northern Nicaragua, an area with a humid tropical climate and a mean annual rainfall of 2770 mm. An analytical method, based on the use of visual indicators, was used to analyze soil erosion by water. This approach enabled us to replicate the method in a sufficiently large number of cases for the results obtained to be considered reliable and representative of the study area. These results indicate that in the agroforestry system examined, for the cultivation of coffee and mixed Shade Trees ( Musa spp and Inga spp ), an average of 10.4% of the area is affected by erosion. The erodibility factors identified were litter layer and slope gradient. The first of these factors accounted for 66% of the variability of erosion, compared with 4% in the second case. The erosion threshold value was between 60 and 65% of the litter layer; beyond this level, the reduction in erosion was statistically significant. With this threshold, the soil was relatively little affected by erosion, around 13% of the cultivated area.

Gerhard Gerold - One of the best experts on this subject based on the ideXlab platform.

  • Shade Trees and tree pruning alter throughfall and microclimate in cocoa (Theobroma cacao L.) production systems
    Annals of Forest Science, 2018
    Co-Authors: Wiebke Niether, Laura Armengot, Christian Andres, Monika Schneider, Gerhard Gerold
    Abstract:

    Key message Shade Trees in agroforestry systems protect the understory cocoa from climate extremes. Shade tree pruning manages microclimatic conditions in favor of cocoa production while tree diversity is maintained. Adaptation of pruning has to consider seasonal changes in temperature and precipitation to protect the understory cocoa. Context Structural characteristics of tree stands such as species diversity, tree density, and stratification can affect throughfall and microclimate. Pruning changes the canopy and may therefore modulate internal conditions. Aims The aim of this study is to assess the environmental growing conditions of cocoa Trees. Methods We monitored canopy openness and the impact of stand structure on throughfall and microclimate in three cocoa production systems (monoculture, agroforestry, and successional agroforestry) and a natural regrowth in a long-term trial in Bolivia from 2013 to 2015. We further focused on the effect of annual Shade tree and cocoa pruning on these variables to evaluate the potential impact of this activity. Results Agroforestry systems buffered extreme climate events like temperature fluctuations compared to monocultures but reduced light and throughfall drastically. Spatial variability of throughfall and transmitted light were low under a high and closed Shade tree canopy. Shade tree pruning resulted in higher canopy openness, light transmittance, and throughfall, while the buffer function of the agroforestry systems concerning temperature and humidity fluctuations was reduced. Conclusion Differences between cocoa production systems regarding throughfall and microclimate were overlain by pruning activities. Cocoa agroforestry systems are temporal dynamic systems. Pruning timing and intensity is pivotal for balancing light and water availability under seasonally varying environmental conditions to conserve micro-environments for cocoa production with less exposure to unfavorable climate.

  • Shade Trees and tree pruning alter throughfall and microclimate in cocoa theobroma cacao l production systems
    Annals of Forest Science, 2018
    Co-Authors: Wiebke Niether, Laura Armengot, Christian Andres, Monika Schneider, Gerhard Gerold
    Abstract:

    Shade Trees in agroforestry systems protect the understory cocoa from climate extremes. Shade tree pruning manages microclimatic conditions in favor of cocoa production while tree diversity is maintained. Adaptation of pruning has to consider seasonal changes in temperature and precipitation to protect the understory cocoa. Context Structural characteristics of tree stands such as species diversity, tree density, and stratification can affect throughfall and microclimate. Pruning changes the canopy and may therefore modulate internal conditions. Aims The aim of this study is to assess the environmental growing conditions of cocoa Trees. Methods We monitored canopy openness and the impact of stand structure on throughfall and microclimate in three cocoa production systems (monoculture, agroforestry, and successional agroforestry) and a natural regrowth in a long-term trial in Bolivia from 2013 to 2015. We further focused on the effect of annual Shade tree and cocoa pruning on these variables to evaluate the potential impact of this activity. Results Agroforestry systems buffered extreme climate events like temperature fluctuations compared to monocultures but reduced light and throughfall drastically. Spatial variability of throughfall and transmitted light were low under a high and closed Shade tree canopy. Shade tree pruning resulted in higher canopy openness, light transmittance, and throughfall, while the buffer function of the agroforestry systems concerning temperature and humidity fluctuations was reduced. Conclusion Differences between cocoa production systems regarding throughfall and microclimate were overlain by pruning activities. Cocoa agroforestry systems are temporal dynamic systems. Pruning timing and intensity is pivotal for balancing light and water availability under seasonally varying environmental conditions to conserve micro-environments for cocoa production with less exposure to unfavorable climate.

Courtney L. Parks - One of the best experts on this subject based on the ideXlab platform.

  • Modeling energy savings from urban Shade Trees: An assessment of the CITYgreen® energy conservation module
    Environmental Management, 2004
    Co-Authors: Andrew D. Carver, Daniel R. Unger, Courtney L. Parks
    Abstract:

    CITYgreen software has become a commonly used tool to quantify the benefits of urban Shade Trees. Despite its frequent use, little research has been conducted to validate results of the CITYgreen energy conservation module. The first objective of this study is to perform a familiar application of CITYgreen software to predict the potential energy savings contribution of existing tree canopies in residential neighborhoods during peak cooling summer months. Unlike previous studies utilizing CITYgreen, this study also seeks to assess the software's performance by comparing model results (i.e., predicted energy savings) with actual savings (i.e., savings derived directly from energy consumption data provided by the electric utility provider). Homeowners in an older neighborhood with established Trees were found to use less energy for air-conditioning than homeowners in a recently developed site. Results from the assessment of model performance indicated that CITYgreen more accurately estimated the energy savings in the highly vegetated, older neighborhood.

Blanco R Sepulveda - One of the best experts on this subject based on the ideXlab platform.

  • soil erosion and erosion thresholds in an agroforestry system of coffee coffea arabica and mixed Shade Trees inga spp and musa spp in northern nicaragua
    Agriculture Ecosystems & Environment, 2015
    Co-Authors: Blanco R Sepulveda, Aguilar A Carrillo
    Abstract:

    Abstract Soil erosion by water is one of the main environmental problems in tropical mountain regions of Central America. Agroforestry systems have been shown to reduce erosion through their canopy cover and their contribution to the litter layer. This paper analyzes the influence of the cover and height of coffee strata and mixed Shade Trees, the ground cover (weeds and litter), the slope gradient and various soil features and characteristics relevant to erosion in six farms that apply the agroforestry system of coffee growing (Coffea arabica) with mixed Shade Trees of Musa spp and Inga spp. We determine the corresponding erosion thresholds, i.e. the value (erodibility factor) beyond which the reduction in erosion becomes statistically significant. A purpose-designed verification method was applied to determine whether the thresholds corresponded to the effective control of erosion. The study area is located in the hills around El Cua, in northern Nicaragua, an area with a humid tropical climate and a mean annual rainfall of 2770 mm. An analytical method, based on the use of visual indicators, was used to analyze soil erosion by water. This approach enabled us to replicate the method in a sufficiently large number of cases for the results obtained to be considered reliable and representative of the study area. These results indicate that in the agroforestry system examined, for the cultivation of coffee and mixed Shade Trees (Musa spp and Inga spp), an average of 10.4% of the area is affected by erosion. The erodibility factors identified were litter layer and slope gradient. The first of these factors accounted for 66% of the variability of erosion, compared with 4% in the second case. The erosion threshold value was between 60 and 65% of the litter layer; beyond this level, the reduction in erosion was statistically significant. With this threshold, the soil was relatively little affected by erosion, around 13% of the cultivated area.

  • soil erosion and erosion thresholds in an agroforestry system of coffee coffea arabica and mixed Shade Trees inga spp and musa spp in northern nicaragua
    Agriculture Ecosystems & Environment, 2015
    Co-Authors: Blanco R Sepulveda, Aguilar A Carrillo
    Abstract:

    Abstract Soil erosion by water is one of the main environmental problems in tropical mountain regions of Central America. Agroforestry systems have been shown to reduce erosion through their canopy cover and their contribution to the litter layer. This paper analyzes the influence of the cover and height of coffee strata and mixed Shade Trees, the ground cover (weeds and litter), the slope gradient and various soil features and characteristics relevant to erosion in six farms that apply the agroforestry system of coffee growing ( Coffea arabica ) with mixed Shade Trees of Musa spp and Inga spp . We determine the corresponding erosion thresholds, i.e. the value (erodibility factor) beyond which the reduction in erosion becomes statistically significant. A purpose-designed verification method was applied to determine whether the thresholds corresponded to the effective control of erosion. The study area is located in the hills around El Cua, in northern Nicaragua, an area with a humid tropical climate and a mean annual rainfall of 2770 mm. An analytical method, based on the use of visual indicators, was used to analyze soil erosion by water. This approach enabled us to replicate the method in a sufficiently large number of cases for the results obtained to be considered reliable and representative of the study area. These results indicate that in the agroforestry system examined, for the cultivation of coffee and mixed Shade Trees ( Musa spp and Inga spp ), an average of 10.4% of the area is affected by erosion. The erodibility factors identified were litter layer and slope gradient. The first of these factors accounted for 66% of the variability of erosion, compared with 4% in the second case. The erosion threshold value was between 60 and 65% of the litter layer; beyond this level, the reduction in erosion was statistically significant. With this threshold, the soil was relatively little affected by erosion, around 13% of the cultivated area.

Vaast Philippe - One of the best experts on this subject based on the ideXlab platform.

  • Young Shade Trees improve soil quality in intensively managed coffee systems recently converted to agroforestry in Yunnan Province, China
    'Springer Science and Business Media LLC', 2020
    Co-Authors: Rigal Clément, Xu Jianchu, Vaast Philippe
    Abstract:

    Background and aims: The trend of soil degradation in intensive open coffee systems is well-documented. This study highlights the impact of young Shade Trees on soil quality only 4 years after their intercropping with coffee. Methods: 18 young Shade Trees belonging to three tree species (Cinnamomum camphora, Bishofia javanica and Jacaranda mimosifolia) were selected in an intensive coffee system in Southern Yunnan. Soil samples (0–20 cm) were tested for chemical composition, soil communities and soil enzyme activities under their canopies and in open areas, both in coffee rows and inter-rows, once during the rainy and once during the dry season. Additionally, root systems were characterized using trenches. Soil water profiles and litterfall were monitored along the production cycle. Coffee yield was recorded for two consecutive years. Results: We detected a positive impact of all Shade tree species on soil chemical, biological and biochemical components, especially during the dry season. This positive impact included higher soil organic matter (+10%) and more abundant soil microbial communities (+64%) under Shaded coffee than under open coffee. Furthermore, Shaded coffee Trees yielded as much as open coffee Trees, except under C. camphora, probably due to high below-ground competition. Conclusions: These results demonstrate that carefully selected Shade Trees can rapidly contribute to preserving and/or restoring soil quality in intensive coffee systems, while maintaining high coffee yield

  • Young Shade Trees improve soil quality in intensively managed coffee systems recently converted to agroforestry in Yunnan Province, China
    Springer Verlag, 2019
    Co-Authors: Rigal Clément, Xu Jianchu, Vaast Philippe
    Abstract:

    International audienceBackground and aims The trend of soil degradation in intensive open coffee systems is well-documented. This study highlights the impact of young Shade Trees on soil quality only 4 years after their intercropping with coffee. Methods 18 young Shade Trees belonging to three tree species (Cinnamomum camphora, Bishofia javanica and Jacaranda mimosifolia) were selected in an intensive coffee system in Southern Yunnan. Soil samples (0-20 cm) were tested for chemical composition, soil communities and soil enzyme activities under their canopies and in open areas, both in coffee rows and inter-rows, once during the rainy and once during the dry season. Additionally, root systems were characterized using trenches. Soil water profiles and litterfall were monitored along the production cycle. Coffee yield was recorded for two consecutive years. Results We detected a positive impact of all Shade tree species on soil chemical, biological and biochemical components, especially during the dry season. This positive impact included higher soil organic matter (+10%) and more abundant soil microbial communities (+64%) under Shaded coffee than under open coffee. Furthermore , Shaded coffee Trees yielded as much as open coffee Trees, except under C. camphora, probably due to high below-ground competition. Conclusions These results demonstrate that carefully selected Shade Trees can rapidly contribute to preserving and/or restoring soil quality in intensive coffee systems, while maintaining high coffee yield

  • Young Shade Trees rapidly improve soil fertility in coffee-agroforestry systems
    'CIRAD (Centre de Cooperation Internationale en Recherche Agronomique Pour le Developpement)', 2019
    Co-Authors: Rigal Clément, Xu J., Vaast Philippe
    Abstract:

    Highly productive monoculture coffee (Coffea arabica L.) farms have rapidly expanded since the 1990s in Yunnan Province, China. In 2013, in order to initiate a large-scale transition towards more sustainable coffee growing practices, local government in southern Yunnan started distributing free Shade tree seedlings to all coffee farmers in their jurisdictions. This study highlights the impact of three of these promoted Shade tree species (Cinnamomum camphora, Bishofia javanica and Jacaranda mimosifolia) on soil fertility and coffee production only four years after their distribution to coffee farmers. Materials and methods Soil samples in the 0-20 cm soil layer were tested for chemical composition (soil organic matter, pH, total N, available P, exchangeable K, Ca and Mg), soil communities (free-living nematodes and microbial communities) and soil enzyme activities (β-glucodidase, N-acetyl-glucosaminidase and acid phosphatase) under Shade Trees (6 replicates per tree species) and in open areas (15 replicates), both in coffee rows and inter-rows, once during the rainy and once during the dry season. Additionally, we characterized root systems and soil water profiles to a depth of 1.2m, monitored litterfall for one year, as well as coffee production for two years. Major results We detected a clear positive impact of all three Shade tree species on soil chemical, biological and biochemical fertility, despite the marked effect of 20 years of high mineral fertilizer inputs. In particular, we measured higher pH and soil organic matter; similar or higher soil enzyme activities throughout the year; more abundant fungi communities throughout the year; and more abundant microbial communities during the dry season below Shade Trees than in open areas. Furthermore, coffee Trees Shaded by B. javanica and J. mimosifolia yielded as much as open coffee Trees. On the other hand, coffee Trees Shaded by C. camphora yielded less than open coffee Trees, most likely as a result of high root competition from this Shade tree species. Lastly, Shade Trees had no visible impact on coffee organoleptic quality. Conclusion These results demonstrate that carefully selected Shade Trees can rapidly contribute to preserving and/or restoring soil fertility in intensive coffee systems, while maintaining high coffee yield