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Raphaël J. Manlay - One of the best experts on this subject based on the ideXlab platform.

  • carbon nitrogen and phosphorus allocation in agro ecosystems of a west african savanna i the Plant Component under semi permanent cultivation
    Agriculture Ecosystems & Environment, 2002
    Co-Authors: Raphaël J. Manlay, M. Kaïré, D. Masse, J.-l. Chotte, Christian Feller, Joel Fardoux, Roger Pontanier
    Abstract:

    Abstract The assessment of carbon (C), nitrogen (N) and phosphorus (P) in agro-ecosystems of West African savannas (WAS) may be a useful tool to define sustainable intensification schemes needed to respond to the rapid increase in local populations as well as global change issues. Changes in soil properties, and particularly in the soil organic matter status, under semi-permanent cultivation were thus examined through a groundnut crop-fallow chronosequence in southern Senegal. The effect of fallowing was mainly restricted to the 0–20 cm soil layer and hardly affected soil physical properties. In this layer, steady improvements were recorded for Mg and Ca contents. Carbon and N amounts increased by 30%, and by 50% for available P (POD) within the very first year of fallow and then remained steady (C and N) or dropped back to levels recorded for crops (POD). The rapid initial change in organic status after crop abandonment was attributed to fast recovery of woody vegetation. The steady soil organic matter (SOM) content in oldest fallows compared to young fallows probably resulted from poor protection of soil organic matter from oxidation during biological activity. This hypothesis was confirmed by mesh-bag experiments, which indicated that >40–60% of decaying woody root biomass disappeared after 6 months of in situ incubation. In fallow systems in southern Senegal, soil fertility may in fact rely at least as much on fast organic matter cycling in soil food webs as on SOM build-up. Carbon storage in the soil-Plant system of mature fallow ecosystems was only 27 t C ha−1 higher than in crops and consisted mainly of pools with fast turnover. Consequently, the potential of semi-permanent cultivation for C sequestration in the WAS will be rather indirect, by a shift to more intensified practices, thus avoiding the conversion of dense forests to cropping in more humid areas.

  • Carbon, nitrogen and phosphorus allocation in agro-ecosystems of a West African savanna I. The Plant Component under semi-permanent cultivation
    Agriculture Ecosystems and Environment, 2002
    Co-Authors: Raphaël J. Manlay, M. Kaïré, D. Masse, J.-l. Chotte, G. Ciornei, C. Floret
    Abstract:

    Organic matter (OM) is both a commodity and a means of production in low-input farming systems of sub-Saharan Africa. Since this resource is becoming increasingly scarce in West African savannas (WAS), there is a need to assess OM, carbon (C), nitrogen (N), and phosphorus (P) allocation in local ecosystems related to land management. Carbon, N and P storage under semi-permanent cultivation in savannas in southern Senegal was thus measured through a chronosequence including 25 groundnut (Arachis hypogaea L.) crops and plots left to fallow for 1-26 years. The amounts of C, N and P in cropped C they increased to 17.7 t C, 231 kg N and 19.6 kg P ha(-1) in fallow plots aged plots were 5.5 t C, 106 kg N and 5.9 kg P ha(-1), 1-9 years. A threshold was reached after 10 years of fallow. Beyond it biomass amounts remained steady. Older fallow plots stored 29 t C, 333 kg N and 33.8 ka P ha(-1). Highest increases in woody Components were found within the very first year following crop abandonment, and were achieved at the expense of the herbaceous layer. Carbon and nutrient allocation to woody below-ground biomass occurred only later. Massive nutrient losses were expected to occur at clearing due to both burning and wood exportation. Because storage in woody and herbaceous biomass remained steady in fallows aged more then 10 years, young fallows were found to have the highest productivity for wood and forage. However, Plant productivity relied on the high resprouting capacity of local tree species, and thus on the maintenance of long breaks of fallow needed for the maintenance of perennial rooting systems. One of the aims of programs to improve the management of fallows, or to replace them with agroforestry techniques, should thus be to preserve perennial rooting systems by any means that are possible in the cropping systems of the WAS. (C) 2002 Elsevier Science B.V All rights reserved.

Roger Pontanier - One of the best experts on this subject based on the ideXlab platform.

  • carbon nitrogen and phosphorus allocation in agro ecosystems of a west african savanna i the Plant Component under semi permanent cultivation
    Agriculture Ecosystems & Environment, 2002
    Co-Authors: Raphaël J. Manlay, M. Kaïré, D. Masse, J.-l. Chotte, Christian Feller, Joel Fardoux, Roger Pontanier
    Abstract:

    Abstract The assessment of carbon (C), nitrogen (N) and phosphorus (P) in agro-ecosystems of West African savannas (WAS) may be a useful tool to define sustainable intensification schemes needed to respond to the rapid increase in local populations as well as global change issues. Changes in soil properties, and particularly in the soil organic matter status, under semi-permanent cultivation were thus examined through a groundnut crop-fallow chronosequence in southern Senegal. The effect of fallowing was mainly restricted to the 0–20 cm soil layer and hardly affected soil physical properties. In this layer, steady improvements were recorded for Mg and Ca contents. Carbon and N amounts increased by 30%, and by 50% for available P (POD) within the very first year of fallow and then remained steady (C and N) or dropped back to levels recorded for crops (POD). The rapid initial change in organic status after crop abandonment was attributed to fast recovery of woody vegetation. The steady soil organic matter (SOM) content in oldest fallows compared to young fallows probably resulted from poor protection of soil organic matter from oxidation during biological activity. This hypothesis was confirmed by mesh-bag experiments, which indicated that >40–60% of decaying woody root biomass disappeared after 6 months of in situ incubation. In fallow systems in southern Senegal, soil fertility may in fact rely at least as much on fast organic matter cycling in soil food webs as on SOM build-up. Carbon storage in the soil-Plant system of mature fallow ecosystems was only 27 t C ha−1 higher than in crops and consisted mainly of pools with fast turnover. Consequently, the potential of semi-permanent cultivation for C sequestration in the WAS will be rather indirect, by a shift to more intensified practices, thus avoiding the conversion of dense forests to cropping in more humid areas.

M. Kaïré - One of the best experts on this subject based on the ideXlab platform.

  • carbon nitrogen and phosphorus allocation in agro ecosystems of a west african savanna i the Plant Component under semi permanent cultivation
    Agriculture Ecosystems & Environment, 2002
    Co-Authors: Raphaël J. Manlay, M. Kaïré, D. Masse, J.-l. Chotte, Christian Feller, Joel Fardoux, Roger Pontanier
    Abstract:

    Abstract The assessment of carbon (C), nitrogen (N) and phosphorus (P) in agro-ecosystems of West African savannas (WAS) may be a useful tool to define sustainable intensification schemes needed to respond to the rapid increase in local populations as well as global change issues. Changes in soil properties, and particularly in the soil organic matter status, under semi-permanent cultivation were thus examined through a groundnut crop-fallow chronosequence in southern Senegal. The effect of fallowing was mainly restricted to the 0–20 cm soil layer and hardly affected soil physical properties. In this layer, steady improvements were recorded for Mg and Ca contents. Carbon and N amounts increased by 30%, and by 50% for available P (POD) within the very first year of fallow and then remained steady (C and N) or dropped back to levels recorded for crops (POD). The rapid initial change in organic status after crop abandonment was attributed to fast recovery of woody vegetation. The steady soil organic matter (SOM) content in oldest fallows compared to young fallows probably resulted from poor protection of soil organic matter from oxidation during biological activity. This hypothesis was confirmed by mesh-bag experiments, which indicated that >40–60% of decaying woody root biomass disappeared after 6 months of in situ incubation. In fallow systems in southern Senegal, soil fertility may in fact rely at least as much on fast organic matter cycling in soil food webs as on SOM build-up. Carbon storage in the soil-Plant system of mature fallow ecosystems was only 27 t C ha−1 higher than in crops and consisted mainly of pools with fast turnover. Consequently, the potential of semi-permanent cultivation for C sequestration in the WAS will be rather indirect, by a shift to more intensified practices, thus avoiding the conversion of dense forests to cropping in more humid areas.

  • Carbon, nitrogen and phosphorus allocation in agro-ecosystems of a West African savanna I. The Plant Component under semi-permanent cultivation
    Agriculture Ecosystems and Environment, 2002
    Co-Authors: Raphaël J. Manlay, M. Kaïré, D. Masse, J.-l. Chotte, G. Ciornei, C. Floret
    Abstract:

    Organic matter (OM) is both a commodity and a means of production in low-input farming systems of sub-Saharan Africa. Since this resource is becoming increasingly scarce in West African savannas (WAS), there is a need to assess OM, carbon (C), nitrogen (N), and phosphorus (P) allocation in local ecosystems related to land management. Carbon, N and P storage under semi-permanent cultivation in savannas in southern Senegal was thus measured through a chronosequence including 25 groundnut (Arachis hypogaea L.) crops and plots left to fallow for 1-26 years. The amounts of C, N and P in cropped C they increased to 17.7 t C, 231 kg N and 19.6 kg P ha(-1) in fallow plots aged plots were 5.5 t C, 106 kg N and 5.9 kg P ha(-1), 1-9 years. A threshold was reached after 10 years of fallow. Beyond it biomass amounts remained steady. Older fallow plots stored 29 t C, 333 kg N and 33.8 ka P ha(-1). Highest increases in woody Components were found within the very first year following crop abandonment, and were achieved at the expense of the herbaceous layer. Carbon and nutrient allocation to woody below-ground biomass occurred only later. Massive nutrient losses were expected to occur at clearing due to both burning and wood exportation. Because storage in woody and herbaceous biomass remained steady in fallows aged more then 10 years, young fallows were found to have the highest productivity for wood and forage. However, Plant productivity relied on the high resprouting capacity of local tree species, and thus on the maintenance of long breaks of fallow needed for the maintenance of perennial rooting systems. One of the aims of programs to improve the management of fallows, or to replace them with agroforestry techniques, should thus be to preserve perennial rooting systems by any means that are possible in the cropping systems of the WAS. (C) 2002 Elsevier Science B.V All rights reserved.

D. Masse - One of the best experts on this subject based on the ideXlab platform.

  • carbon nitrogen and phosphorus allocation in agro ecosystems of a west african savanna i the Plant Component under semi permanent cultivation
    Agriculture Ecosystems & Environment, 2002
    Co-Authors: Raphaël J. Manlay, M. Kaïré, D. Masse, J.-l. Chotte, Christian Feller, Joel Fardoux, Roger Pontanier
    Abstract:

    Abstract The assessment of carbon (C), nitrogen (N) and phosphorus (P) in agro-ecosystems of West African savannas (WAS) may be a useful tool to define sustainable intensification schemes needed to respond to the rapid increase in local populations as well as global change issues. Changes in soil properties, and particularly in the soil organic matter status, under semi-permanent cultivation were thus examined through a groundnut crop-fallow chronosequence in southern Senegal. The effect of fallowing was mainly restricted to the 0–20 cm soil layer and hardly affected soil physical properties. In this layer, steady improvements were recorded for Mg and Ca contents. Carbon and N amounts increased by 30%, and by 50% for available P (POD) within the very first year of fallow and then remained steady (C and N) or dropped back to levels recorded for crops (POD). The rapid initial change in organic status after crop abandonment was attributed to fast recovery of woody vegetation. The steady soil organic matter (SOM) content in oldest fallows compared to young fallows probably resulted from poor protection of soil organic matter from oxidation during biological activity. This hypothesis was confirmed by mesh-bag experiments, which indicated that >40–60% of decaying woody root biomass disappeared after 6 months of in situ incubation. In fallow systems in southern Senegal, soil fertility may in fact rely at least as much on fast organic matter cycling in soil food webs as on SOM build-up. Carbon storage in the soil-Plant system of mature fallow ecosystems was only 27 t C ha−1 higher than in crops and consisted mainly of pools with fast turnover. Consequently, the potential of semi-permanent cultivation for C sequestration in the WAS will be rather indirect, by a shift to more intensified practices, thus avoiding the conversion of dense forests to cropping in more humid areas.

  • Carbon, nitrogen and phosphorus allocation in agro-ecosystems of a West African savanna I. The Plant Component under semi-permanent cultivation
    Agriculture Ecosystems and Environment, 2002
    Co-Authors: Raphaël J. Manlay, M. Kaïré, D. Masse, J.-l. Chotte, G. Ciornei, C. Floret
    Abstract:

    Organic matter (OM) is both a commodity and a means of production in low-input farming systems of sub-Saharan Africa. Since this resource is becoming increasingly scarce in West African savannas (WAS), there is a need to assess OM, carbon (C), nitrogen (N), and phosphorus (P) allocation in local ecosystems related to land management. Carbon, N and P storage under semi-permanent cultivation in savannas in southern Senegal was thus measured through a chronosequence including 25 groundnut (Arachis hypogaea L.) crops and plots left to fallow for 1-26 years. The amounts of C, N and P in cropped C they increased to 17.7 t C, 231 kg N and 19.6 kg P ha(-1) in fallow plots aged plots were 5.5 t C, 106 kg N and 5.9 kg P ha(-1), 1-9 years. A threshold was reached after 10 years of fallow. Beyond it biomass amounts remained steady. Older fallow plots stored 29 t C, 333 kg N and 33.8 ka P ha(-1). Highest increases in woody Components were found within the very first year following crop abandonment, and were achieved at the expense of the herbaceous layer. Carbon and nutrient allocation to woody below-ground biomass occurred only later. Massive nutrient losses were expected to occur at clearing due to both burning and wood exportation. Because storage in woody and herbaceous biomass remained steady in fallows aged more then 10 years, young fallows were found to have the highest productivity for wood and forage. However, Plant productivity relied on the high resprouting capacity of local tree species, and thus on the maintenance of long breaks of fallow needed for the maintenance of perennial rooting systems. One of the aims of programs to improve the management of fallows, or to replace them with agroforestry techniques, should thus be to preserve perennial rooting systems by any means that are possible in the cropping systems of the WAS. (C) 2002 Elsevier Science B.V All rights reserved.

J.-l. Chotte - One of the best experts on this subject based on the ideXlab platform.

  • carbon nitrogen and phosphorus allocation in agro ecosystems of a west african savanna i the Plant Component under semi permanent cultivation
    Agriculture Ecosystems & Environment, 2002
    Co-Authors: Raphaël J. Manlay, M. Kaïré, D. Masse, J.-l. Chotte, Christian Feller, Joel Fardoux, Roger Pontanier
    Abstract:

    Abstract The assessment of carbon (C), nitrogen (N) and phosphorus (P) in agro-ecosystems of West African savannas (WAS) may be a useful tool to define sustainable intensification schemes needed to respond to the rapid increase in local populations as well as global change issues. Changes in soil properties, and particularly in the soil organic matter status, under semi-permanent cultivation were thus examined through a groundnut crop-fallow chronosequence in southern Senegal. The effect of fallowing was mainly restricted to the 0–20 cm soil layer and hardly affected soil physical properties. In this layer, steady improvements were recorded for Mg and Ca contents. Carbon and N amounts increased by 30%, and by 50% for available P (POD) within the very first year of fallow and then remained steady (C and N) or dropped back to levels recorded for crops (POD). The rapid initial change in organic status after crop abandonment was attributed to fast recovery of woody vegetation. The steady soil organic matter (SOM) content in oldest fallows compared to young fallows probably resulted from poor protection of soil organic matter from oxidation during biological activity. This hypothesis was confirmed by mesh-bag experiments, which indicated that >40–60% of decaying woody root biomass disappeared after 6 months of in situ incubation. In fallow systems in southern Senegal, soil fertility may in fact rely at least as much on fast organic matter cycling in soil food webs as on SOM build-up. Carbon storage in the soil-Plant system of mature fallow ecosystems was only 27 t C ha−1 higher than in crops and consisted mainly of pools with fast turnover. Consequently, the potential of semi-permanent cultivation for C sequestration in the WAS will be rather indirect, by a shift to more intensified practices, thus avoiding the conversion of dense forests to cropping in more humid areas.

  • Carbon, nitrogen and phosphorus allocation in agro-ecosystems of a West African savanna I. The Plant Component under semi-permanent cultivation
    Agriculture Ecosystems and Environment, 2002
    Co-Authors: Raphaël J. Manlay, M. Kaïré, D. Masse, J.-l. Chotte, G. Ciornei, C. Floret
    Abstract:

    Organic matter (OM) is both a commodity and a means of production in low-input farming systems of sub-Saharan Africa. Since this resource is becoming increasingly scarce in West African savannas (WAS), there is a need to assess OM, carbon (C), nitrogen (N), and phosphorus (P) allocation in local ecosystems related to land management. Carbon, N and P storage under semi-permanent cultivation in savannas in southern Senegal was thus measured through a chronosequence including 25 groundnut (Arachis hypogaea L.) crops and plots left to fallow for 1-26 years. The amounts of C, N and P in cropped C they increased to 17.7 t C, 231 kg N and 19.6 kg P ha(-1) in fallow plots aged plots were 5.5 t C, 106 kg N and 5.9 kg P ha(-1), 1-9 years. A threshold was reached after 10 years of fallow. Beyond it biomass amounts remained steady. Older fallow plots stored 29 t C, 333 kg N and 33.8 ka P ha(-1). Highest increases in woody Components were found within the very first year following crop abandonment, and were achieved at the expense of the herbaceous layer. Carbon and nutrient allocation to woody below-ground biomass occurred only later. Massive nutrient losses were expected to occur at clearing due to both burning and wood exportation. Because storage in woody and herbaceous biomass remained steady in fallows aged more then 10 years, young fallows were found to have the highest productivity for wood and forage. However, Plant productivity relied on the high resprouting capacity of local tree species, and thus on the maintenance of long breaks of fallow needed for the maintenance of perennial rooting systems. One of the aims of programs to improve the management of fallows, or to replace them with agroforestry techniques, should thus be to preserve perennial rooting systems by any means that are possible in the cropping systems of the WAS. (C) 2002 Elsevier Science B.V All rights reserved.