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Registro Completo
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Biblioteca(s): |
Embrapa Instrumentação. |
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Data corrente: |
28/04/2003 |
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Data da última atualização: |
28/04/2003 |
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Autoria: |
BAYER, C.; MIELNICZUK, J.; MARTIN-NETO, L.; ERNANI, P. R. |
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Afiliação: |
UFRGS, Departamento de Solos, Porto Alegre, RS; Embrapa Instrumentação Agropecuária, São Carlos, SP; UFSC, Departamento de Solos, Lages, SC. |
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Título: |
Stocks and humidification degree of organic matter fractions as affected by no-tillage on a subtropical soil. |
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Ano de publicação: |
2002 |
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Fonte/Imprenta: |
Plant and Soil, Hague, v. 238, p. 133-140, 2002. |
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Idioma: |
Inglês |
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Conteúdo: |
Assessment of particulata (>53-mi) and mineral-associated (<53-mi) soil organic matter (SOM) fractions is a useful approach to understand the dynamic of organic matter in soils. This study aimed to compare the long-term (9-yr) effects of no-tillage (NT) and conventional tillage (CT) on C and N stocks in the two above mentioned organic fractions in a Brazilian Acrisol. The degree of SOM humification, which has been associated with the concentration of semiquinone-type free radicals ("spin") determined by electron spin resonance (ESR), was also evaluated. Soil under no-tillage had 7.55 Mg ha-1 (25%0 more C and 741 kg ha-1 (29%) more Ne than conventionally tilled soil in the 0-175-mm depth. Both particulate and mineral-associated SOM increased in the no-tilled soil. The incrase of C and N stocks in the mineral-associated SOM accounted for 75% and 91% of the difference in total soil C and N stocks between NT and CT, respectively. Averaged across tillage systems, C and N stocks were respectively 4.6 and 16.8 times higher in the mineal-associated SOM than in particulate SOM. The higher C and N stocks were associated with greater recalcitrance of mineral-associated SOM to biological decomposition, resultin, probably, from its interaction with variable charge minerals. This is corroborated by a positive relationship between concentrations of C and iron oxides and kaolinite in the 53-20, 20-2 and <2-mi particle size classes, of the 0-25-mm soil layer. The degree of SOM humification, assessed by ESR, decreased in both the 53-20 and 20-2-mi fractions under NT. However, it was unaffected by tillage in the <2-mi fraction, which mormally presented the lowest "spin" concentration. Since quality as well as quantity of SOM improved in the no-tillage soil, adoption of this system is highly recommended for amelioration of degraded tropical and sutropical solis. MenosAssessment of particulata (>53-mi) and mineral-associated (<53-mi) soil organic matter (SOM) fractions is a useful approach to understand the dynamic of organic matter in soils. This study aimed to compare the long-term (9-yr) effects of no-tillage (NT) and conventional tillage (CT) on C and N stocks in the two above mentioned organic fractions in a Brazilian Acrisol. The degree of SOM humification, which has been associated with the concentration of semiquinone-type free radicals ("spin") determined by electron spin resonance (ESR), was also evaluated. Soil under no-tillage had 7.55 Mg ha-1 (25%0 more C and 741 kg ha-1 (29%) more Ne than conventionally tilled soil in the 0-175-mm depth. Both particulate and mineral-associated SOM increased in the no-tilled soil. The incrase of C and N stocks in the mineral-associated SOM accounted for 75% and 91% of the difference in total soil C and N stocks between NT and CT, respectively. Averaged across tillage systems, C and N stocks were respectively 4.6 and 16.8 times higher in the mineal-associated SOM than in particulate SOM. The higher C and N stocks were associated with greater recalcitrance of mineral-associated SOM to biological decomposition, resultin, probably, from its interaction with variable charge minerals. This is corroborated by a positive relationship between concentrations of C and iron oxides and kaolinite in the 53-20, 20-2 and <2-mi particle size classes, of the 0-25-mm soil layer. The degree of SOM humification,... Mostrar Tudo |
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Palavras-Chave: |
Clima subtropical; Electron spin resonance; Grau de humificação; Particulate soil organic matter; Subtropical climate. |
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Thesagro: |
Matéria Orgânica; Solo. |
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Thesaurus NAL: |
no-tillage. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 02632naa a2200253 a 4500
001 1024620
005 2003-04-28
008 2002 bl --- 0-- u #d
100 1 $aBAYER, C.
245 $aStocks and humidification degree of organic matter fractions as affected by no-tillage on a subtropical soil.
260 $c2002
520 $aAssessment of particulata (>53-mi) and mineral-associated (<53-mi) soil organic matter (SOM) fractions is a useful approach to understand the dynamic of organic matter in soils. This study aimed to compare the long-term (9-yr) effects of no-tillage (NT) and conventional tillage (CT) on C and N stocks in the two above mentioned organic fractions in a Brazilian Acrisol. The degree of SOM humification, which has been associated with the concentration of semiquinone-type free radicals ("spin") determined by electron spin resonance (ESR), was also evaluated. Soil under no-tillage had 7.55 Mg ha-1 (25%0 more C and 741 kg ha-1 (29%) more Ne than conventionally tilled soil in the 0-175-mm depth. Both particulate and mineral-associated SOM increased in the no-tilled soil. The incrase of C and N stocks in the mineral-associated SOM accounted for 75% and 91% of the difference in total soil C and N stocks between NT and CT, respectively. Averaged across tillage systems, C and N stocks were respectively 4.6 and 16.8 times higher in the mineal-associated SOM than in particulate SOM. The higher C and N stocks were associated with greater recalcitrance of mineral-associated SOM to biological decomposition, resultin, probably, from its interaction with variable charge minerals. This is corroborated by a positive relationship between concentrations of C and iron oxides and kaolinite in the 53-20, 20-2 and <2-mi particle size classes, of the 0-25-mm soil layer. The degree of SOM humification, assessed by ESR, decreased in both the 53-20 and 20-2-mi fractions under NT. However, it was unaffected by tillage in the <2-mi fraction, which mormally presented the lowest "spin" concentration. Since quality as well as quantity of SOM improved in the no-tillage soil, adoption of this system is highly recommended for amelioration of degraded tropical and sutropical solis.
650 $ano-tillage
650 $aMatéria Orgânica
650 $aSolo
653 $aClima subtropical
653 $aElectron spin resonance
653 $aGrau de humificação
653 $aParticulate soil organic matter
653 $aSubtropical climate
700 1 $aMIELNICZUK, J.
700 1 $aMARTIN-NETO, L.
700 1 $aERNANI, P. R.
773 $tPlant and Soil, Hague$gv. 238, p. 133-140, 2002.
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