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Registro Completo |
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Biblioteca(s): |
Embrapa Agrobiologia. |
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Data corrente: |
02/06/2000 |
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Data da última atualização: |
02/06/2000 |
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Autoria: |
FREY, S. D.; ELLIOTT, E. T.; PAUSTIAN, K. |
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Título: |
Bacterial and fungal abundance and biomass in conventional and no-tillage agroecosystems along two climatic gradients. |
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Ano de publicação: |
1999 |
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Fonte/Imprenta: |
Soil Biology and Biochemistry, Oxford, v. 31, p. 573-585, 1999. |
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Idioma: |
Inglês |
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Conteúdo: |
Microbial community composition may be an important determinant of soil organic matter (SOM) decomposition rates and nutrient turnover and availability in agricultural soils. Soil samples were collected from six long-term tillage comparison experiments located along two climatic gradients to examine the effects of no-tillage (NT) and conventional tillage (CT) management on bacterial and fungal abundance and biomass and to examine potential controls on the relative abundances of bacteria and fungi in these two systems. Samples were divided into 0-5 and 5-20 cm depth increments and analyzed for bacterial and fungal abundance and biomass, total C and N, particulate organic matter C and N (POM-C and N), soil water content, texture, pH, and water-stable aggregate distributions. Soil moisture, which varied by tillage treatment and geographically with climate, ranged from 0.05 to 0.35 g g-1 dry soil in the surface 0-5 cm and 0.15 to 0.28 g g-1 dry soil at 5-20 cm. Measured organic matter C and N fractions and mean weight diameter (MWD) of water-stable aggregates were significantly higher in NT relative to CT at three of the six sites. Fungal hyphal length ranged from 19 to 292 m g-1 soil and was 1.9 to 2.5 times higher in NT compared to CT surface soil across all sites. Few significant tillage treatment differences in soil physical and chemical properties or in fungal abundance and biomass were observed at 5-20 cm. Bacterial abundance and biomass were not consistently influenced by tillage treatment or site location at either depth. The proportion of the total biomass composed of fungi ranged from 10 to 60% and was significantly higher in NT compared to CT surface soil at five of six sites. Proportional fungal biomass was not strongly related to soil texture, pH, aggregation, or organic C and N fractions, but was positively related to soil moisture (r=0.67; P menor 0.001). The relationship between soil moisture and the degree of fungal dominance was due to the positive response of fungal biomass and the lack of response of bacterial biomass to increasing soil moisture across the range of measured soil water contents. Tillage treatment effects on fungal biomass and proportional fungal abundance were not significant when the data were analyzed by analysis of covariance with soil moisture as the covariate. These results suggest that observed tillage treatment and climate gradient effects on fungi are related to differences in soil moisture. Further research is needed, however, to determine how tillage-induced changes in the soil environment shape microbial community composition in agroecosystems. MenosMicrobial community composition may be an important determinant of soil organic matter (SOM) decomposition rates and nutrient turnover and availability in agricultural soils. Soil samples were collected from six long-term tillage comparison experiments located along two climatic gradients to examine the effects of no-tillage (NT) and conventional tillage (CT) management on bacterial and fungal abundance and biomass and to examine potential controls on the relative abundances of bacteria and fungi in these two systems. Samples were divided into 0-5 and 5-20 cm depth increments and analyzed for bacterial and fungal abundance and biomass, total C and N, particulate organic matter C and N (POM-C and N), soil water content, texture, pH, and water-stable aggregate distributions. Soil moisture, which varied by tillage treatment and geographically with climate, ranged from 0.05 to 0.35 g g-1 dry soil in the surface 0-5 cm and 0.15 to 0.28 g g-1 dry soil at 5-20 cm. Measured organic matter C and N fractions and mean weight diameter (MWD) of water-stable aggregates were significantly higher in NT relative to CT at three of the six sites. Fungal hyphal length ranged from 19 to 292 m g-1 soil and was 1.9 to 2.5 times higher in NT compared to CT surface soil across all sites. Few significant tillage treatment differences in soil physical and chemical properties or in fungal abundance and biomass were observed at 5-20 cm. Bacterial abundance and biomass were not consistently influenced by... Mostrar Tudo |
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Palavras-Chave: |
Agroecossistema; Biomassa microbiana; Direct sowing; Soil chemicophysical properties; Soil moisture; Soil physical; Zero tillage. |
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Thesagro: |
Física do Solo; Fungo; Matéria Orgânica; Método Estatístico; Plantio Direto; Umidade do Solo. |
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Thesaurus Nal: |
agroecosystems; analysis of variance; fungi; microbial biomass; no-tillage; organic matter; soil water content; statistical analysis. |
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Categoria do assunto: |
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Marc: |
LEADER 03774naa a2200397 a 4500
001 1621173
005 2000-06-02
008 1999 bl --- 0-- u #d
100 1 $aFREY, S. D.
245 $aBacterial and fungal abundance and biomass in conventional and no-tillage agroecosystems along two climatic gradients.
260 $c1999
520 $aMicrobial community composition may be an important determinant of soil organic matter (SOM) decomposition rates and nutrient turnover and availability in agricultural soils. Soil samples were collected from six long-term tillage comparison experiments located along two climatic gradients to examine the effects of no-tillage (NT) and conventional tillage (CT) management on bacterial and fungal abundance and biomass and to examine potential controls on the relative abundances of bacteria and fungi in these two systems. Samples were divided into 0-5 and 5-20 cm depth increments and analyzed for bacterial and fungal abundance and biomass, total C and N, particulate organic matter C and N (POM-C and N), soil water content, texture, pH, and water-stable aggregate distributions. Soil moisture, which varied by tillage treatment and geographically with climate, ranged from 0.05 to 0.35 g g-1 dry soil in the surface 0-5 cm and 0.15 to 0.28 g g-1 dry soil at 5-20 cm. Measured organic matter C and N fractions and mean weight diameter (MWD) of water-stable aggregates were significantly higher in NT relative to CT at three of the six sites. Fungal hyphal length ranged from 19 to 292 m g-1 soil and was 1.9 to 2.5 times higher in NT compared to CT surface soil across all sites. Few significant tillage treatment differences in soil physical and chemical properties or in fungal abundance and biomass were observed at 5-20 cm. Bacterial abundance and biomass were not consistently influenced by tillage treatment or site location at either depth. The proportion of the total biomass composed of fungi ranged from 10 to 60% and was significantly higher in NT compared to CT surface soil at five of six sites. Proportional fungal biomass was not strongly related to soil texture, pH, aggregation, or organic C and N fractions, but was positively related to soil moisture (r=0.67; P menor 0.001). The relationship between soil moisture and the degree of fungal dominance was due to the positive response of fungal biomass and the lack of response of bacterial biomass to increasing soil moisture across the range of measured soil water contents. Tillage treatment effects on fungal biomass and proportional fungal abundance were not significant when the data were analyzed by analysis of covariance with soil moisture as the covariate. These results suggest that observed tillage treatment and climate gradient effects on fungi are related to differences in soil moisture. Further research is needed, however, to determine how tillage-induced changes in the soil environment shape microbial community composition in agroecosystems.
650 $aagroecosystems
650 $aanalysis of variance
650 $afungi
650 $amicrobial biomass
650 $ano-tillage
650 $aorganic matter
650 $asoil water content
650 $astatistical analysis
650 $aFísica do Solo
650 $aFungo
650 $aMatéria Orgânica
650 $aMétodo Estatístico
650 $aPlantio Direto
650 $aUmidade do Solo
653 $aAgroecossistema
653 $aBiomassa microbiana
653 $aDirect sowing
653 $aSoil chemicophysical properties
653 $aSoil moisture
653 $aSoil physical
653 $aZero tillage
700 1 $aELLIOTT, E. T.
700 1 $aPAUSTIAN, K.
773 $tSoil Biology and Biochemistry, Oxford$gv. 31, p. 573-585, 1999.
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Registro original: |
Embrapa Agrobiologia (CNPAB) |
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