Data/hora: 26/05/2024 00:47:11

Biblioteca(s): 	Embrapa Agrobiologia.	
Data corrente: 	27/12/2000	
Data da última atualização: 	27/12/2000	
Autoria: 	TRANNIN, W. S.; URQUIAGA, S.; GUERRA, J. G. M.; IBIJBJEN, J.; CADISCH, G.	
Título: 	Interspecies competition and N transfer in a tropical grass-legume mixture.	
Ano de publicação: 	2000	
Fonte/Imprenta: 	Biology and Fertility of Soils, Berlin, v. 32, n. 6, p. 441-448, 2000.	
Idioma: 	Inglês	
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. 

	
Palavras-Chave: 	Arbuscular mycorrhizae vesicular; Biological nitrogen fixation; BNF; FBN; Fixação biológica de nitrogênio.	
Thesagro: 	Brachiaria Decumbens; Micorriza Vesicular Arbuscular; Stylosanthes Guianensis.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Agrobiologia (CNPAB)	
Exemplares: 	CNPAB - (916-1) - UPC - SP - -- -  -  - 0022530 - DIS