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Registro Completo |
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Biblioteca(s): |
Embrapa Trigo. |
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Data corrente: |
10/01/2010 |
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Data da última atualização: |
19/12/2012 |
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Autoria: |
BURNS, R. G.; AUDUS, L. J. |
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Título: |
Distribution and breakdown of paraquat in soil. |
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Ano de publicação: |
1970 |
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Fonte/Imprenta: |
Weed Research, Oxford, v. 10, n. 1, p. 49-58, 1970. |
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Idioma: |
Inglês |
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Conteúdo: |
The degradation of paraquat dichloride in soil by Lipomyces starkeyi Lod. and Rij, was investigated spectrophotometrically and by 14C-labelled carbon dioxide emission. Breakdown occurred within the first 96 hr of incubation in cultures of soil of high organic content. Adsorption isotherms showed that soils rich in organic matter had a greater total adsorption of paraquat from solutions of concentration in excess of 250 ppm. Soil high in organic matter was fractionated by ultrasonic disintegration into its organic and inorganic components. Paraquat degradation occurred in cultures containing the former but not the latter. Slow transfer of 14C-labelled paraquat adsorbed on the organic components was shown to take place through a dialysis membrane to the much stronger adsorption sites on the inorganic components placed outside the membrane.
It appears that decomposition of paraquat in soil by L. starkeyi occurs while the herbicide is weakly adsorbed on the organic soil components. Over a period of time (96 hr in one instance), slow transfer to the inorganic soil components rendered the paraquat unavailable for microbial degradation. |
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Palavras-Chave: |
Constituintes; Diferentes camadas do solo; Diminuição; Distribuição; Efeito; Solo (adsorção). |
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Thesagro: |
Paraquat. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 01713naa a2200217 a 4500
001 1831465
005 2012-12-19
008 1970 bl --- 0-- u #d
100 1 $aBURNS, R. G.
245 $aDistribution and breakdown of paraquat in soil.
260 $c1970
520 $aThe degradation of paraquat dichloride in soil by Lipomyces starkeyi Lod. and Rij, was investigated spectrophotometrically and by 14C-labelled carbon dioxide emission. Breakdown occurred within the first 96 hr of incubation in cultures of soil of high organic content. Adsorption isotherms showed that soils rich in organic matter had a greater total adsorption of paraquat from solutions of concentration in excess of 250 ppm. Soil high in organic matter was fractionated by ultrasonic disintegration into its organic and inorganic components. Paraquat degradation occurred in cultures containing the former but not the latter. Slow transfer of 14C-labelled paraquat adsorbed on the organic components was shown to take place through a dialysis membrane to the much stronger adsorption sites on the inorganic components placed outside the membrane. It appears that decomposition of paraquat in soil by L. starkeyi occurs while the herbicide is weakly adsorbed on the organic soil components. Over a period of time (96 hr in one instance), slow transfer to the inorganic soil components rendered the paraquat unavailable for microbial degradation.
650 $aParaquat
653 $aConstituintes
653 $aDiferentes camadas do solo
653 $aDiminuição
653 $aDistribuição
653 $aEfeito
653 $aSolo (adsorção)
700 1 $aAUDUS, L. J.
773 $tWeed Research, Oxford$gv. 10, n. 1, p. 49-58, 1970.
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Embrapa Trigo (CNPT) |
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