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Dirk Holscher - One of the best experts on this subject based on the ideXlab platform.
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effects of an experimental drought on the functioning of a cacao agroforestry system sulawesi indonesia
Global Change Biology, 2010Co-Authors: Luitgard Schwendenmann, Edzo Veldkamp, Iswandi Anas, Gunawan Djajakirana, Stefan Erasmi, Gerald Moser, Yann Clough, Dirk Holscher, Dietrich HertelAbstract:Agroforestry systems may play a critical role in reducing the vulnerability of farmers’ livelihood to droughts as tree-based systems provide several mechanisms that can mitigate the impacts from extreme weather events. Here, we use a replicated throughfall reduction experiment to study the drought response of a cacao/Gliricidia stand over a 13-month period. Soil water content was successfully reduced down to a soil depth of at least 2.5 m. Contrary to our expectations we measured only relatively small nonsignificant changes in cacao (� 11%) and Gliricidia (� 12%) sap flux densities, cacao leaf litterfall ( 1 8%), Gliricidia leaf litterfall (� 2%), soil carbon dioxide efflux (� 14%), and cacao yield (� 10%) during roof closure. However, cacao bean yield in roof plots was substantially lower (� 45%) compared with control plots during the main harvest following the period when soil water content was lowest. This indicates that cacao bean yield was more sensitive to drought than other ecosystem functions. We found evidence in this agroforest that there is complementary use of soil water resources through vertical partitioning of water uptake between cacao and Gliricidia. This, in combination with acclimation may have helped cacao trees to cope with the induced drought. Cacao agroforests may thus play an important role as a drought-tolerant land use in those (sub-) tropical regions where the frequency and severity of droughts is projected to increase.
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response of cocoa trees theobroma cacao to a 13 month desiccation period in sulawesi indonesia
Agroforestry Systems, 2010Co-Authors: Gerald Moser, Dietrich Hertel, Dirk Holscher, Christoph Leuschner, M Kohler, Daniela Leitner, Beate Michalzik, Erma Prihastanti, Soekisman Tjitrosemito, Luitgard SchwendenmannAbstract:In South-east Asia, ENSO-related droughts represent irregularly occurring hazards for agroforestry systems containing cocoa which are predicted to increase in severity with expected climate warming. To characterize the drought response of mature cocoa trees, we conducted the Sulawesi Throughfall Displacement Experiment in a shaded (Gliricidia sepium) cocoa agroforestry system in Central Sulawesi, Indonesia. Three large sub-canopy roofs were installed to reduce throughfall by about 80% over a 13-month period to test the hypotheses that (i) cocoa trees are sensitive to drought due to their shallow fine root system, and (ii) bean yield is more sensitive to drought than leaf or stem growth. As 83% of fine root (diameter 2 mm) was located in the upper 40 cm of the soil, the cocoa trees examined had a very shallow root system. Cocoa and Gliricidia differed in their vertical rooting patterns, thereby reducing competition for water. Despite being exposed for several months to soil water contents close to the conventional wilting point, cocoa trees showed no significant decreases in leaf biomass, stem and branch wood production or fine root biomass. Possible causes are active osmotic adjustment in roots, mitigation of drought stress by shading from Gliricidia or other factors. By contrast, production of cocoa beans was significantly reduced in the roof plots, supporting reports of substantial reductions in bean yields during ENSO-related drought events in the region. We conclude that cocoa possesses traits related to drought tolerance which enable it to maintain biomass production during extended dry periods, whereas bean yield appears to be particularly drought sensitive.
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water use characteristics of cacao and Gliricidia trees in an agroforest in central sulawesi indonesia
Ecohydrology, 2009Co-Authors: M Kohler, Luitgard Schwendenmann, Diego Dierick, Dirk HolscherAbstract:Water use characteristics of cacao (Theobroma cacao) and Gliricidia sepium shade trees were studied in an agroforest on Sulawesi, Indonesia. The objectives were: (1) to identify environmental and tree structural factors controlling water use, (2) to analyse the effect of shade tree cover on cacao water use and (3) to estimate stand level transpiration. Sap flux density was measured in up to 18 trees per species and described with a Jarvis-type model. Model parameters suggested a 49% higher maximum sap flux density in cacao than in Gliricidia and species differences in the response to vapour pressure deficit and radiation. Tree water use was positively related to tree diameter in both species, but this relationship tended to differ between species. In cacao trees maximal tree water use increased with decreasing canopy gap fraction above the trees (R 2 adj = 0.39, p = 0.04). This was paralleled by an increase of cacao stem diameter and leaf area with decreasing gap fraction. Maximum water use rate per unit crown area of cacao was 13% higher than that of Gliricidia. At the stand level the average transpiration rate was estimated at 1.5 mm day -1 per unit ground area, 70% of which was contributed to by cacao. We conclude that, in the given stand, species differed substantially in water use characteristics, while estimated stand transpiration is in line with findings from other studies for cacao stands. Shade trees may enhance stand transpiration through own water use and additionally by increasing water use rates of cacao trees.
Luitgard Schwendenmann - One of the best experts on this subject based on the ideXlab platform.
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effects of an experimental drought on the functioning of a cacao agroforestry system sulawesi indonesia
Global Change Biology, 2010Co-Authors: Luitgard Schwendenmann, Edzo Veldkamp, Iswandi Anas, Gunawan Djajakirana, Stefan Erasmi, Gerald Moser, Yann Clough, Dirk Holscher, Dietrich HertelAbstract:Agroforestry systems may play a critical role in reducing the vulnerability of farmers’ livelihood to droughts as tree-based systems provide several mechanisms that can mitigate the impacts from extreme weather events. Here, we use a replicated throughfall reduction experiment to study the drought response of a cacao/Gliricidia stand over a 13-month period. Soil water content was successfully reduced down to a soil depth of at least 2.5 m. Contrary to our expectations we measured only relatively small nonsignificant changes in cacao (� 11%) and Gliricidia (� 12%) sap flux densities, cacao leaf litterfall ( 1 8%), Gliricidia leaf litterfall (� 2%), soil carbon dioxide efflux (� 14%), and cacao yield (� 10%) during roof closure. However, cacao bean yield in roof plots was substantially lower (� 45%) compared with control plots during the main harvest following the period when soil water content was lowest. This indicates that cacao bean yield was more sensitive to drought than other ecosystem functions. We found evidence in this agroforest that there is complementary use of soil water resources through vertical partitioning of water uptake between cacao and Gliricidia. This, in combination with acclimation may have helped cacao trees to cope with the induced drought. Cacao agroforests may thus play an important role as a drought-tolerant land use in those (sub-) tropical regions where the frequency and severity of droughts is projected to increase.
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response of cocoa trees theobroma cacao to a 13 month desiccation period in sulawesi indonesia
Agroforestry Systems, 2010Co-Authors: Gerald Moser, Dietrich Hertel, Dirk Holscher, Christoph Leuschner, M Kohler, Daniela Leitner, Beate Michalzik, Erma Prihastanti, Soekisman Tjitrosemito, Luitgard SchwendenmannAbstract:In South-east Asia, ENSO-related droughts represent irregularly occurring hazards for agroforestry systems containing cocoa which are predicted to increase in severity with expected climate warming. To characterize the drought response of mature cocoa trees, we conducted the Sulawesi Throughfall Displacement Experiment in a shaded (Gliricidia sepium) cocoa agroforestry system in Central Sulawesi, Indonesia. Three large sub-canopy roofs were installed to reduce throughfall by about 80% over a 13-month period to test the hypotheses that (i) cocoa trees are sensitive to drought due to their shallow fine root system, and (ii) bean yield is more sensitive to drought than leaf or stem growth. As 83% of fine root (diameter 2 mm) was located in the upper 40 cm of the soil, the cocoa trees examined had a very shallow root system. Cocoa and Gliricidia differed in their vertical rooting patterns, thereby reducing competition for water. Despite being exposed for several months to soil water contents close to the conventional wilting point, cocoa trees showed no significant decreases in leaf biomass, stem and branch wood production or fine root biomass. Possible causes are active osmotic adjustment in roots, mitigation of drought stress by shading from Gliricidia or other factors. By contrast, production of cocoa beans was significantly reduced in the roof plots, supporting reports of substantial reductions in bean yields during ENSO-related drought events in the region. We conclude that cocoa possesses traits related to drought tolerance which enable it to maintain biomass production during extended dry periods, whereas bean yield appears to be particularly drought sensitive.
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water use characteristics of cacao and Gliricidia trees in an agroforest in central sulawesi indonesia
Ecohydrology, 2009Co-Authors: M Kohler, Luitgard Schwendenmann, Diego Dierick, Dirk HolscherAbstract:Water use characteristics of cacao (Theobroma cacao) and Gliricidia sepium shade trees were studied in an agroforest on Sulawesi, Indonesia. The objectives were: (1) to identify environmental and tree structural factors controlling water use, (2) to analyse the effect of shade tree cover on cacao water use and (3) to estimate stand level transpiration. Sap flux density was measured in up to 18 trees per species and described with a Jarvis-type model. Model parameters suggested a 49% higher maximum sap flux density in cacao than in Gliricidia and species differences in the response to vapour pressure deficit and radiation. Tree water use was positively related to tree diameter in both species, but this relationship tended to differ between species. In cacao trees maximal tree water use increased with decreasing canopy gap fraction above the trees (R 2 adj = 0.39, p = 0.04). This was paralleled by an increase of cacao stem diameter and leaf area with decreasing gap fraction. Maximum water use rate per unit crown area of cacao was 13% higher than that of Gliricidia. At the stand level the average transpiration rate was estimated at 1.5 mm day -1 per unit ground area, 70% of which was contributed to by cacao. We conclude that, in the given stand, species differed substantially in water use characteristics, while estimated stand transpiration is in line with findings from other studies for cacao stands. Shade trees may enhance stand transpiration through own water use and additionally by increasing water use rates of cacao trees.
Gudeta W. Sileshi - One of the best experts on this subject based on the ideXlab platform.
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impact of Gliricidia sepium intercropping on soil organic matter fractions in a maize based cropping system
Agriculture Ecosystems & Environment, 2010Co-Authors: Tracy Beedy, Festus K Akinnifesi, Sieglinde S Snapp, Gudeta W. SileshiAbstract:Abstract The Gliricidia ( Gliricidia sepium )/maize intercropping system holds promise for increasing productivity in maize-based cropping systems on depleted soils in Southern Africa. The effect of the intercrop on soil properties was investigated to better understand soil processes underlying maize yield response, soil nutrient recapitalization and soil carbon sequestration. Soil organic matter (SOM) fractions, particulate organic matter (POM), POM-carbon, POM-nitrogen, soil nutrient status and underlying soil characteristics were quantified on the 14th year of a Gliricidia/maize intercrop establish in 1991 on a Ferric Lixisol in southern Malawi. A factorial design compared the intercrop and a sole maize crop at three rates of added inorganic nitrogen (N) and phosphorus (P). Gliricidia leaf biomass was incorporated into the maize three times per year. Soil was sampled to a 20 cm depth, post-harvest to analyze biophysical and chemical characteristics of soil organic matter, POM, POM-C and POM-N, as well as inorganic N, available P, exchangeable K + and particle size distribution. The Gliricidia/maize intercrop had a significant and positive effect on SOM, POM, and SOM fractions: SOM was 12% higher, POM 40%, POM-C 62%, and POM-N 86% higher in the Gliricidia intercrop compared to sole maize, indicating nitrogen enrichment of POM. Nitrogen fertilizer was associated with modest increases in POM, 15% in Gliricidia and 27% in sole maize. The impacts of these changes were directed mostly at increasing maize yields and increasing storage of soil nutrients over the short term, while decreasing the proportion of organic matter stored over the long term. Both the Gliricidia/maize intercrop and increasing soil clay content were associated with significantly increased soil CEC. The Gliricidia intercrop maintained CEC in coarse-textured soils over a 14-year time span, indicating a role for legume trees in intensified cropping of coarse-textured soils.
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synergistic effect of inorganic n and p fertilizers and organic inputs from Gliricidia sepium on productivity of intercropped maize in southern malawi
Plant and Soil, 2007Co-Authors: Festus K Akinnifesi, Gudeta W. Sileshi, Wilkson Makumba, Oluyede C Ajayi, David MwetaAbstract:In Malawi, N and P deficiencies have been identified as major soil fertility constraints to maize (Zea mays, hybrid NSCM 41) productivity. In this study, we evaluated the effect of three rates of N and P fertilizers on maize performance in monoculture and maize intercropped with the nitrogen fixing legume Gliricidia (Gliricidia sepium) in replicated field trials run for four years (2002/03-2005/06 seasons) at Makoka, in southern Malawi. Significant season-to-season variation was found in stand loss, ears per plant, stover yield, grain yield and thousand kernel weight (TKW), which was related to distribution of rainfall received during the growing season. All variables were significantly higher in the Gliricidia/maize intercrop compared with monoculture maize. During the four consecutive cropping seasons, grain yields of maize increased by 343% (i.e. from 0.94 tons ha−1 in unfertilized sole maize to 4.17 tons ha−1 in Gliricidia/maize intercropping). Optimum synergistic effect on grain yield (38% increase over unfertilized Gliricidia/maize) was obtained when half recommended N and P rates were combined with Gliricidia indicating interspecific facilitation. Response surface modelling showed that the optimum combination of factors for maximum grain yield (4.2 t ha-1) in monoculture maize was 80 kg N ha-1, 31 kg P ha-1 and 917 mm seasonal rainfall. In the Gliricidia/maize intercrop, the stationary point had no unique maximum. Ridge analysis revealed that the estimated ridge of maximum grain yield (5.7 t ha-1) in the intercrop is when 69 kg N ha-1, 37 kg P ha-1 is applied and a seasonal rainfall of 977 mm is received. The total P uptake in the intercrop (14.3 kg ha-1) was significantly higher than that in maize monoculture (6.6 kg ha-1). P uptake was significantly (P = 0.008) influenced by P fertilizer rate. Therefore, we conclude that combining inorganic N and P fertilizers with organic inputs from Gliricidia has positive and synergistic effects on maize productivity in southern Malawi.
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farmer participatory evaluation of the potential for organic vegetable production in the wetlands of zambia
Outlook on Agriculture, 2006Co-Authors: Elias Kuntashula, Gudeta W. Sileshi, Paramu L. Mafongoya, J. BandaAbstract:Although wetlands (locally called dambos) are considered extremely vulnerable to poor agricultural practices, rising population pressures have caused their agricultural use to become increasingly important. Intensification of dambo use by way of chemical fertilizer and pesticide applications poses serious challenges to their ecological sustainability. This study evaluated Gliricidia (Gliricidia sepium) leafy biomass as a possible alternative to commercial fertilizer, and Tephrosia (Tephrosia vogelii) leaf extract, commercial formulations of neem seed extract (Achook) and Bacillus thuringiensis (Thuricide) as alternatives to chemical pesticides in the production of cabbage in dambos. The study showed that soil fertility management practices can significantly influence the time to harvest the cabbage crop and its yield. Vegetables grown using Gliricidia biomass produced significantly higher yields compared with the no-input option. The population density of diamondback moth (Plutella xylostella) larvae, the percentage of plants infested by cabbage webworm (Hellula undalis) and cabbage aphid (Brevocoryne brassicae) was significantly lower in cabbage treated with sprays of Tephrosia leaf extract and Achook. It is concluded that Gliricidia leafy biomass as a soil fertility management practice combined with Tephrosia leaf extract and neem seed extract as a crop protection practice could increase the productivity of cabbage and ensure sustainable utilization of dambos.
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long term effects of improved legume fallows on soil invertebrate macrofauna and maize yield in eastern zambia
Agriculture Ecosystems & Environment, 2006Co-Authors: Gudeta W. Sileshi, Paramu L. MafongoyaAbstract:Abstract Though improved fallows have been widely promoted as low-input technologies suitable for soil fertility replenishment in smallholder agriculture in southern Africa, their interaction with soil invertebrates has not been studied. In the present study we compared the population of soil macrofauna in maize grown in Gliricidia (Gliricidia sepium), leucaena (Leucaena leucocephala), Leucaena diversifolia, sesbania (Sesbania sesban) and acacia (Acacia anguistissima) and continuously cropped monoculture maize. The objectives of the study were to determine (1) the effect of the type and length of fallows on soil macrofauna communities and functional groups, and (2) the long-term effect of legume fallows on maize yield. The number of invertebrate orders per sampling unit was significantly influenced by the type of fallow but not by the length of fallow period. Maize grown in legume fallows had more numbers of invertebrate orders than monoculture maize. Among the soil invertebrate macrofauna, centipede and millipede populations were significantly influenced by fallow type. The density of earthworms varied with both the type and length of fallow practice. Earthworm populations under maize grown in Gliricidia fallows were significantly higher than those under fully fertilized monoculture maize. The population densities of other invertebrate orders and functional groups did not significantly differ between maize grown continuously in monoculture and in legume fallows. The highest maize grain yield (3.0–6.0 t ha−1) was recorded in fully fertilized monoculture. Maize grown in Gliricidia and leucaena fallows consistently gave 2.0–4.0 t ha−1 throughout the study period, while maize grown without fertilizer yielded less than 2 t ha−1. These legumes produced 0.4–2.9 t ha−1 of re-sprout biomass annually, which released nutrients contributing to higher maize yields over a long period of time. It is concluded that these legume fallows can improve maize yields in addition to their positive impact on the diversity and functions of soil invertebrates.
Joanne F. Jamie - One of the best experts on this subject based on the ideXlab platform.
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isoflavonoids and a pterocarpan from Gliricidia sepium
Phytochemistry, 1998Co-Authors: H. M. M. T. B. Herath, Rohan Suranga Dassanayake, A M A Priyadarshani, Susila De Silva, G. P. Wannigama, Joanne F. JamieAbstract:A new isoflavan, 7,4′-dihydroxy-3′-methoxyisoflavan has been isolated from the insecticidally active hot dichloromethane extract of the heartwood of Gliricidia sepium, along with the three other isoflavonoids, isovestitol, formononetin and afrormosin, a pterocarpan, medicarpin and 4-hydroxy-3-methoxycinnamaldehyde which are new to this species.
Paramu L. Mafongoya - One of the best experts on this subject based on the ideXlab platform.
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nutrient dynamics in wetland organic vegetable production systems in eastern zambia
Sustainable Agriculture Research, 2016Co-Authors: Paramu L. Mafongoya, Obert JiriAbstract:The aim of this study was to determine effects of organic inputs on vegetable crops and on a subsequent maize crop grown in wetlands. The following treatments were applied to cabbage (Brassica oleracea) and onion (Allium cepa) crops: Gliricidia sepium (Gliricidia) biomass (8 t ha-1), Gliricidia biomass (12 t ha-1), cattle manure (10 t ha-1) with half recommended fertilizer rate, and recommended fertilizer rate (800 kg ha-1 basal dressing and 250 kg ha-1 top dressing fertilizer). The residual effect of the treatments was tested on a subsequent maize crop. The soil at the sites had low organic matter content (average 2%) and it was acidic (average pH 4.4). Soil inorganic N increased significantly from 11 mg kg-1 in the unfertilized crop to 22 mg kg-1 in the Gliricidia treatments after cabbage, and from 10.3 mg kg-1 to 37.2 mg kg-1 after the onion crop. There were significant differences (P<0.05) in onion and cabbage yields and in subsequent maize yield in both cabbage and onion plots. This study concluded that the application of high quality Gliricidia prunings lead to rapid release of N and higher vegetable yields. However, there is a high amount of residual N that can be leached.
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farmer participatory evaluation of the potential for organic vegetable production in the wetlands of zambia
Outlook on Agriculture, 2006Co-Authors: Elias Kuntashula, Gudeta W. Sileshi, Paramu L. Mafongoya, J. BandaAbstract:Although wetlands (locally called dambos) are considered extremely vulnerable to poor agricultural practices, rising population pressures have caused their agricultural use to become increasingly important. Intensification of dambo use by way of chemical fertilizer and pesticide applications poses serious challenges to their ecological sustainability. This study evaluated Gliricidia (Gliricidia sepium) leafy biomass as a possible alternative to commercial fertilizer, and Tephrosia (Tephrosia vogelii) leaf extract, commercial formulations of neem seed extract (Achook) and Bacillus thuringiensis (Thuricide) as alternatives to chemical pesticides in the production of cabbage in dambos. The study showed that soil fertility management practices can significantly influence the time to harvest the cabbage crop and its yield. Vegetables grown using Gliricidia biomass produced significantly higher yields compared with the no-input option. The population density of diamondback moth (Plutella xylostella) larvae, the percentage of plants infested by cabbage webworm (Hellula undalis) and cabbage aphid (Brevocoryne brassicae) was significantly lower in cabbage treated with sprays of Tephrosia leaf extract and Achook. It is concluded that Gliricidia leafy biomass as a soil fertility management practice combined with Tephrosia leaf extract and neem seed extract as a crop protection practice could increase the productivity of cabbage and ensure sustainable utilization of dambos.
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long term effects of improved legume fallows on soil invertebrate macrofauna and maize yield in eastern zambia
Agriculture Ecosystems & Environment, 2006Co-Authors: Gudeta W. Sileshi, Paramu L. MafongoyaAbstract:Abstract Though improved fallows have been widely promoted as low-input technologies suitable for soil fertility replenishment in smallholder agriculture in southern Africa, their interaction with soil invertebrates has not been studied. In the present study we compared the population of soil macrofauna in maize grown in Gliricidia (Gliricidia sepium), leucaena (Leucaena leucocephala), Leucaena diversifolia, sesbania (Sesbania sesban) and acacia (Acacia anguistissima) and continuously cropped monoculture maize. The objectives of the study were to determine (1) the effect of the type and length of fallows on soil macrofauna communities and functional groups, and (2) the long-term effect of legume fallows on maize yield. The number of invertebrate orders per sampling unit was significantly influenced by the type of fallow but not by the length of fallow period. Maize grown in legume fallows had more numbers of invertebrate orders than monoculture maize. Among the soil invertebrate macrofauna, centipede and millipede populations were significantly influenced by fallow type. The density of earthworms varied with both the type and length of fallow practice. Earthworm populations under maize grown in Gliricidia fallows were significantly higher than those under fully fertilized monoculture maize. The population densities of other invertebrate orders and functional groups did not significantly differ between maize grown continuously in monoculture and in legume fallows. The highest maize grain yield (3.0–6.0 t ha−1) was recorded in fully fertilized monoculture. Maize grown in Gliricidia and leucaena fallows consistently gave 2.0–4.0 t ha−1 throughout the study period, while maize grown without fertilizer yielded less than 2 t ha−1. These legumes produced 0.4–2.9 t ha−1 of re-sprout biomass annually, which released nutrients contributing to higher maize yields over a long period of time. It is concluded that these legume fallows can improve maize yields in addition to their positive impact on the diversity and functions of soil invertebrates.