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Registro Completo
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Biblioteca(s): |
Embrapa Agrobiologia. |
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Data corrente: |
09/08/2004 |
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Data da última atualização: |
09/08/2004 |
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Autoria: |
BODDEY, R. M.; MACEDO, R.; TARRÉ, R. M.; FERREIRA, E.; OLIVEIRA, O. C. de; REZENDE, C. de P.; CANTARUTTI, R. B.; PEREIRA, J. M.; ALVES, B. J. R.; URQUIAGA, S. |
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Título: |
Nitrogen cycling in Brachiaria pastures: the key to understanding the process of pasture decline. |
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Ano de publicação: |
2004 |
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Fonte/Imprenta: |
Agriculture Ecosystems & Environment, Amsterdam, v. 103, p. 389-403, 2004. |
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Idioma: |
Inglês |
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Conteúdo: |
In the tropical regions of Brazil there are at leas 80 million ha Mha of pastures planted to grasses introduced from Africa, principaly Brachiaria spp. It is estamated at least half of theses pastures are degraded, that is, support very low stocking rates, show low plant cover, are invaded by-non-palatable native species and often densely populated with termite mounds. The main causes of the process of pature decline are lack of maintenance fertilisation and excessively high animal stocking rates. In this study the of increasing stockingrate on the fluxes of nitrogen N though the animal (forage consumiption, production of faeces and urine) and through the plant (growth, senescence) pathways were studied on Brachiaria humidicola pastures grazed by Zebu beef cattle in the Atlantic fores region of south of (Brazil). As stocking rate increased from 2 to 4animals ha -1, live weight gain per animal decreased from 153 to 120 kg per animal per year but overall weight gain per hectare increased from 305 to 360 kg per vear. Nitrogen exported in the animal weight gain only increased from 7.3 to 8.6 kg N ha-1, but the pathways of Ncycling were radically changed. Increasing the stocking rate from 2 to 4 animal ha-1, increased total Nconsumed by the animal from 94 to 158 kb ha-1 per year, and that deposited in plant litter decreased from 170 to 105 kg ha-1.This resulted in increases in N deposited as urine and dung in the paddocks from 50 to 90 and 37 to 59 kg ha-1, respectively. A large proportion of the excretions were deposited in rest ares and around drinking troughs where the grass was so trampled that it coud not take advantage of thisN, and other nutrients. Data from complementary studies showed that N losses from urine could be between 35 and 80%, being much higher in without vegetation. Weconclude that decline is hastened by increasing stocking rates because of these losses of N and decrease in N nutrients available for grass growth. MenosIn the tropical regions of Brazil there are at leas 80 million ha Mha of pastures planted to grasses introduced from Africa, principaly Brachiaria spp. It is estamated at least half of theses pastures are degraded, that is, support very low stocking rates, show low plant cover, are invaded by-non-palatable native species and often densely populated with termite mounds. The main causes of the process of pature decline are lack of maintenance fertilisation and excessively high animal stocking rates. In this study the of increasing stockingrate on the fluxes of nitrogen N though the animal (forage consumiption, production of faeces and urine) and through the plant (growth, senescence) pathways were studied on Brachiaria humidicola pastures grazed by Zebu beef cattle in the Atlantic fores region of south of (Brazil). As stocking rate increased from 2 to 4animals ha -1, live weight gain per animal decreased from 153 to 120 kg per animal per year but overall weight gain per hectare increased from 305 to 360 kg per vear. Nitrogen exported in the animal weight gain only increased from 7.3 to 8.6 kg N ha-1, but the pathways of Ncycling were radically changed. Increasing the stocking rate from 2 to 4 animal ha-1, increased total Nconsumed by the animal from 94 to 158 kb ha-1 per year, and that deposited in plant litter decreased from 170 to 105 kg ha-1.This resulted in increases in N deposited as urine and dung in the paddocks from 50 to 90 and 37 to 59 kg ha-1, respectively. A larg... Mostrar Tudo |
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Palavras-Chave: |
Brcahiaria grass; Cycling; Litters; Nitrogen cycle in ecosystems. |
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Thesagro: |
Brachiaria; Brachiaria Humidicola; Capim Brachiaria; Ciclo do Nitrogênio; Feno; Pastagem. |
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Thesaurus NAL: |
pastures. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 02972naa a2200361 a 4500
001 1624696
005 2004-08-09
008 2004 bl --- 0-- u #d
100 1 $aBODDEY, R. M.
245 $aNitrogen cycling in Brachiaria pastures$bthe key to understanding the process of pasture decline.
260 $c2004
520 $aIn the tropical regions of Brazil there are at leas 80 million ha Mha of pastures planted to grasses introduced from Africa, principaly Brachiaria spp. It is estamated at least half of theses pastures are degraded, that is, support very low stocking rates, show low plant cover, are invaded by-non-palatable native species and often densely populated with termite mounds. The main causes of the process of pature decline are lack of maintenance fertilisation and excessively high animal stocking rates. In this study the of increasing stockingrate on the fluxes of nitrogen N though the animal (forage consumiption, production of faeces and urine) and through the plant (growth, senescence) pathways were studied on Brachiaria humidicola pastures grazed by Zebu beef cattle in the Atlantic fores region of south of (Brazil). As stocking rate increased from 2 to 4animals ha -1, live weight gain per animal decreased from 153 to 120 kg per animal per year but overall weight gain per hectare increased from 305 to 360 kg per vear. Nitrogen exported in the animal weight gain only increased from 7.3 to 8.6 kg N ha-1, but the pathways of Ncycling were radically changed. Increasing the stocking rate from 2 to 4 animal ha-1, increased total Nconsumed by the animal from 94 to 158 kb ha-1 per year, and that deposited in plant litter decreased from 170 to 105 kg ha-1.This resulted in increases in N deposited as urine and dung in the paddocks from 50 to 90 and 37 to 59 kg ha-1, respectively. A large proportion of the excretions were deposited in rest ares and around drinking troughs where the grass was so trampled that it coud not take advantage of thisN, and other nutrients. Data from complementary studies showed that N losses from urine could be between 35 and 80%, being much higher in without vegetation. Weconclude that decline is hastened by increasing stocking rates because of these losses of N and decrease in N nutrients available for grass growth.
650 $apastures
650 $aBrachiaria
650 $aBrachiaria Humidicola
650 $aCapim Brachiaria
650 $aCiclo do Nitrogênio
650 $aFeno
650 $aPastagem
653 $aBrcahiaria grass
653 $aCycling
653 $aLitters
653 $aNitrogen cycle in ecosystems
700 1 $aMACEDO, R.
700 1 $aTARRÉ, R. M.
700 1 $aFERREIRA, E.
700 1 $aOLIVEIRA, O. C. de
700 1 $aREZENDE, C. de P.
700 1 $aCANTARUTTI, R. B.
700 1 $aPEREIRA, J. M.
700 1 $aALVES, B. J. R.
700 1 $aURQUIAGA, S.
773 $tAgriculture Ecosystems & Environment, Amsterdam$gv. 103, p. 389-403, 2004.
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