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Registro Completo |
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Biblioteca(s): |
Embrapa Agrobiologia. |
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Data corrente: |
27/12/2000 |
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Data da última atualização: |
27/12/2000 |
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Autoria: |
TRANNIN, W. S.; URQUIAGA, S.; GUERRA, J. G. M.; IBIJBJEN, J.; CADISCH, G. |
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Título: |
Interspecies competition and N transfer in a tropical grass-legume mixture. |
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Ano de publicação: |
2000 |
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Fonte/Imprenta: |
Biology and Fertility of Soils, Berlin, v. 32, n. 6, p. 441-448, 2000. |
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Idioma: |
Inglês |
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Conteúdo: |
Competitiveness of Brachiaria decumbens cv. Basilisk and Stylosanthes guianensis cv. Minerão was investigated either without root restriction or by separating their root systems with a fine mesh or a solid barrier in the presence or absence of mycorrhiza ( Glomus clarum ). Nitrogen transfer between the legume and the grass was assessed with the 15N isotope dilution technique using a relatively stable 15N-enriched soil derived from a long-term labelling experiment. During establishment, legume development was severely restricted by competition from the grass in pots without a root barrier. However, as the system became N limited, the legume became dominant due to its access to atmospheric N2 which contributed over 80% of the legume N requirements. S. guianensis was highly mycotrophic and inoculation with mycorrhiza favoured rapid establishment even in the treatments with no root barrier. Only in the presence of root barriers, either a mesh or a complete compartment separation, was the proportion of N derived from N2 fixation positively affected by the presence of the fungus. No significant direct belowground N transfer from legume to grass was observed during the lifetime of the legume suggesting that the legume maintains a highly efficient recycling under N-limited conditions. However, after cutting the shoot at ground leveI, the grass assimilated significant amounts of N de- rived from decaying legume roots. We conclude that the main pathway of belowground N transfer from S. guianensis to associated B. decumbens occurred via de- composing roots rather than via root exudates or direct mycorrhizal hyphae transfer. MenosCompetitiveness of Brachiaria decumbens cv. Basilisk and Stylosanthes guianensis cv. Minerão was investigated either without root restriction or by separating their root systems with a fine mesh or a solid barrier in the presence or absence of mycorrhiza ( Glomus clarum ). Nitrogen transfer between the legume and the grass was assessed with the 15N isotope dilution technique using a relatively stable 15N-enriched soil derived from a long-term labelling experiment. During establishment, legume development was severely restricted by competition from the grass in pots without a root barrier. However, as the system became N limited, the legume became dominant due to its access to atmospheric N2 which contributed over 80% of the legume N requirements. S. guianensis was highly mycotrophic and inoculation with mycorrhiza favoured rapid establishment even in the treatments with no root barrier. Only in the presence of root barriers, either a mesh or a complete compartment separation, was the proportion of N derived from N2 fixation positively affected by the presence of the fungus. No significant direct belowground N transfer from legume to grass was observed during the lifetime of the legume suggesting that the legume maintains a highly efficient recycling under N-limited conditions. However, after cutting the shoot at ground leveI, the grass assimilated significant amounts of N de- rived from decaying legume roots. We conclude that the main pathway of belowground N transfer from ... Mostrar Tudo |
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Palavras-Chave: |
Arbuscular mycorrhizae vesicular; Biological nitrogen fixation; BNF; FBN; Fixação biológica de nitrogênio. |
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Thesagro: |
Brachiaria Decumbens; Micorriza Vesicular Arbuscular; Stylosanthes Guianensis. |
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Categoria do assunto: |
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Marc: |
LEADER 02441naa a2200265 a 4500
001 1597294
005 2000-12-27
008 2000 bl --- 0-- u #d
100 1 $aTRANNIN, W. S.
245 $aInterspecies competition and N transfer in a tropical grass-legume mixture.
260 $c2000
520 $aCompetitiveness of Brachiaria decumbens cv. Basilisk and Stylosanthes guianensis cv. Minerão was investigated either without root restriction or by separating their root systems with a fine mesh or a solid barrier in the presence or absence of mycorrhiza ( Glomus clarum ). Nitrogen transfer between the legume and the grass was assessed with the 15N isotope dilution technique using a relatively stable 15N-enriched soil derived from a long-term labelling experiment. During establishment, legume development was severely restricted by competition from the grass in pots without a root barrier. However, as the system became N limited, the legume became dominant due to its access to atmospheric N2 which contributed over 80% of the legume N requirements. S. guianensis was highly mycotrophic and inoculation with mycorrhiza favoured rapid establishment even in the treatments with no root barrier. Only in the presence of root barriers, either a mesh or a complete compartment separation, was the proportion of N derived from N2 fixation positively affected by the presence of the fungus. No significant direct belowground N transfer from legume to grass was observed during the lifetime of the legume suggesting that the legume maintains a highly efficient recycling under N-limited conditions. However, after cutting the shoot at ground leveI, the grass assimilated significant amounts of N de- rived from decaying legume roots. We conclude that the main pathway of belowground N transfer from S. guianensis to associated B. decumbens occurred via de- composing roots rather than via root exudates or direct mycorrhizal hyphae transfer.
650 $aBrachiaria Decumbens
650 $aMicorriza Vesicular Arbuscular
650 $aStylosanthes Guianensis
653 $aArbuscular mycorrhizae vesicular
653 $aBiological nitrogen fixation
653 $aBNF
653 $aFBN
653 $aFixação biológica de nitrogênio
700 1 $aURQUIAGA, S.
700 1 $aGUERRA, J. G. M.
700 1 $aIBIJBJEN, J.
700 1 $aCADISCH, G.
773 $tBiology and Fertility of Soils, Berlin$gv. 32, n. 6, p. 441-448, 2000.
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Registro original: |
Embrapa Agrobiologia (CNPAB) |
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| 1. |  | TRANNIN, W. S.; URQUIAGA, S.; GUERRA, J. G. M.; IBIJBJEN, J.; CADISCH, G. Interspecies competition and N transfer in a tropical grass-legume mixture. Biology and Fertility of Soils, Berlin, v. 32, n. 6, p. 441-448, 2000.| Biblioteca(s): Embrapa Agrobiologia. |
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