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Registro Completo |
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Biblioteca(s): |
Embrapa Gado de Corte. |
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Data corrente: |
16/06/2004 |
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Data da última atualização: |
16/06/2004 |
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Autoria: |
NAKAMURA, T.; KANNO, T.; OHWAKI, Y.; MIRANDA, C. H. B.; MACEDO, M. C. M.; FUKUDA, E. |
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Afiliação: |
JIRCAS (Owashi, Japão). |
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Título: |
Characterization of nitrogen utilization by tropical grasses in Brazilian savannas. |
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Ano de publicação: |
2003 |
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Fonte/Imprenta: |
In: SUENAGA, K.; OSHIBE, A.; TANIGUHI, T. (Ed.). Development of sustainable agro-pastoral systems in the subtropical zone of Brazil. Tsukuba: JIRCAS, 2004. |
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Páginas: |
p. 25-28. |
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Série: |
(JIRCAS. Working Report, 36). |
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Idioma: |
Inglês |
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Notas: |
CNPGC. Proceedings of the Workshop on the results and prospects of comprehensive studies on the development of sustainable agro-pastoral systems in the subtropical zone of Brazil, 2003.
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Conteúdo: |
Brachiaria species are widely cultivated in the Brazilian savanna (Cerrados). The poor nitrogen (N) fertility of soils is one of the limiting factors of grass production in this area. Thus, the mechanism of absorption and utilization in these grasses are needed to be celar under N-limiting condition. In this research, we compared the characteristics of N utilization inBrachiaria brizantha (BB), B decumbens (BD), and B. humidicola (BR), which are widely cultivated in this area. Firstly, in the pot experiment, BB, BD, and BH were grown under 3 levels of N, equivalent to ) (ON), 50 (IN), and 150 (2N) kg N ha, with N as ammonium sulfate. The dry mater production of these 3 varieties, as affected by N nutrition, was then compared. The dry mass quickly decreased with reduction of applied N level in BB and BD. In BH, however, the reduction was smaller than those of the other 2 grasses specially when N was not applied. These data suggest that BH was more adapted to limited-N conditions than the other 2 grasses. In the ON treatment, especially N absorption in plant was higher in BH than in the other 2 grasses. Scondly, the contribution ratio of fixed N from air in plant (%Ndfa) of Brachiaria species was also estimated in N-limiting condition in field. The estimated contibution ratio of N fixation was 1-29% and this ratio of BH was lower than that of BD and BB. Thus, contribution ratio of soil-N would be higher in BH tan in other 2 grasses. Thirdly. Michaelis-mentens kinetic analysis was conducted to evaluate physiological traits of roots to N. In the nitrato uptake experiment, the value of Km was lower in BH than in the other 2 grasses. This result could indicate that, as BH has higher affinity for nitrate uptake, due to its low km, it may maintain a higher N uptake rate in N-limiting condition. Therefore, it could be considered that the smaller reduction of dry mass of BH in low-N conditions is due to high-N absorption rate in its roots. MenosBrachiaria species are widely cultivated in the Brazilian savanna (Cerrados). The poor nitrogen (N) fertility of soils is one of the limiting factors of grass production in this area. Thus, the mechanism of absorption and utilization in these grasses are needed to be celar under N-limiting condition. In this research, we compared the characteristics of N utilization inBrachiaria brizantha (BB), B decumbens (BD), and B. humidicola (BR), which are widely cultivated in this area. Firstly, in the pot experiment, BB, BD, and BH were grown under 3 levels of N, equivalent to ) (ON), 50 (IN), and 150 (2N) kg N ha, with N as ammonium sulfate. The dry mater production of these 3 varieties, as affected by N nutrition, was then compared. The dry mass quickly decreased with reduction of applied N level in BB and BD. In BH, however, the reduction was smaller than those of the other 2 grasses specially when N was not applied. These data suggest that BH was more adapted to limited-N conditions than the other 2 grasses. In the ON treatment, especially N absorption in plant was higher in BH than in the other 2 grasses. Scondly, the contribution ratio of fixed N from air in plant (%Ndfa) of Brachiaria species was also estimated in N-limiting condition in field. The estimated contibution ratio of N fixation was 1-29% and this ratio of BH was lower than that of BD and BB. Thus, contribution ratio of soil-N would be higher in BH tan in other 2 grasses. Thirdly. Michaelis-mentens kine... Mostrar Tudo |
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Palavras-Chave: |
Brasil; Brazilian savannas; Marandu. |
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Thesagro: |
Brachiaria Brizantha; Brachiaria Decumbens; Brachiaria Humidicola; Cerrado; Fertilizante Nitrogenado; Nitrogênio; Pastagem. |
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Thesaurus Nal: |
Brazil; nitrogen; pastures. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 03245naa a2200373 a 4500
001 1323192
005 2004-06-16
008 2003 bl uuuu u00u1 u #d
100 1 $aNAKAMURA, T.
245 $aCharacterization of nitrogen utilization by tropical grasses in Brazilian savannas.
260 $c2003
300 $ap. 25-28.
490 $a(JIRCAS. Working Report, 36).
500 $aCNPGC. Proceedings of the Workshop on the results and prospects of comprehensive studies on the development of sustainable agro-pastoral systems in the subtropical zone of Brazil, 2003.
520 $aBrachiaria species are widely cultivated in the Brazilian savanna (Cerrados). The poor nitrogen (N) fertility of soils is one of the limiting factors of grass production in this area. Thus, the mechanism of absorption and utilization in these grasses are needed to be celar under N-limiting condition. In this research, we compared the characteristics of N utilization inBrachiaria brizantha (BB), B decumbens (BD), and B. humidicola (BR), which are widely cultivated in this area. Firstly, in the pot experiment, BB, BD, and BH were grown under 3 levels of N, equivalent to ) (ON), 50 (IN), and 150 (2N) kg N ha, with N as ammonium sulfate. The dry mater production of these 3 varieties, as affected by N nutrition, was then compared. The dry mass quickly decreased with reduction of applied N level in BB and BD. In BH, however, the reduction was smaller than those of the other 2 grasses specially when N was not applied. These data suggest that BH was more adapted to limited-N conditions than the other 2 grasses. In the ON treatment, especially N absorption in plant was higher in BH than in the other 2 grasses. Scondly, the contribution ratio of fixed N from air in plant (%Ndfa) of Brachiaria species was also estimated in N-limiting condition in field. The estimated contibution ratio of N fixation was 1-29% and this ratio of BH was lower than that of BD and BB. Thus, contribution ratio of soil-N would be higher in BH tan in other 2 grasses. Thirdly. Michaelis-mentens kinetic analysis was conducted to evaluate physiological traits of roots to N. In the nitrato uptake experiment, the value of Km was lower in BH than in the other 2 grasses. This result could indicate that, as BH has higher affinity for nitrate uptake, due to its low km, it may maintain a higher N uptake rate in N-limiting condition. Therefore, it could be considered that the smaller reduction of dry mass of BH in low-N conditions is due to high-N absorption rate in its roots.
650 $aBrazil
650 $anitrogen
650 $apastures
650 $aBrachiaria Brizantha
650 $aBrachiaria Decumbens
650 $aBrachiaria Humidicola
650 $aCerrado
650 $aFertilizante Nitrogenado
650 $aNitrogênio
650 $aPastagem
653 $aBrasil
653 $aBrazilian savannas
653 $aMarandu
700 1 $aKANNO, T.
700 1 $aOHWAKI, Y.
700 1 $aMIRANDA, C. H. B.
700 1 $aMACEDO, M. C. M.
700 1 $aFUKUDA, E.
773 $tIn: SUENAGA, K.; OSHIBE, A.; TANIGUHI, T. (Ed.). Development of sustainable agro-pastoral systems in the subtropical zone of Brazil. Tsukuba: JIRCAS, 2004.
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Embrapa Gado de Corte (CNPGC) |
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| 1. |  | OVERBECK, G. E.; HERMANN, J.-M.; ANDRADE, B. O.; BOLDRINI, I. I.; KIEHL, K.; KIRMER, A.; KOCH, C.; KOLLMANN, J.; MEYER, S. T.; MÜLLER, S. C.; NABINGER, C.; PILGER, G. E.; TRINDADE, J. P. P.; VÉLEZ-MARTIN, E.; WALKER, E. A.; ZIMMERMANN, D. G.; PILLAR, V. D. Restoration ecology in Brazil - time to step out of the forest. Natureza & Conservação, Curitiba, v. 11, n. 1, p. 92-95, jul. 2013.| Tipo: Artigo em Periódico Indexado | Circulação/Nível: A - 2 |
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