Microbial biomass in agricultural topsoils after 6 years of bare fallow
ISSN: |
1432-0789
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Keywords: |
Microbial biomass ; Bare fallow ; Microbial: organic C ratio ; Catalase activity ; Earthworms
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Source: |
Springer Online Journal Archives 1860-2000
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Topics: |
Biology
Geosciences
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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Notes: |
Abstract Inherent soil properties have an influence on microbial activity. These effects were measured in a field trial at Weihenstephan with 30 agricultural and 2 vineyard soils from different sites in Bavaria which had been kept under bare fallow for 6 years. The soils represented a wide range of arable soils from a temperate climate. Unaffected by recent differences in climatic conditions or cropping managements, they were used to assess the relationship between microbial biomass C and a broad spectrum of soil physical and chemical properties (clay content 5–63%, pH 4.5–7.5, organic C 0.55–2.93%). Microbial C was measured using the substrate-induced respiration method. In addition, soil catalase activity and the abundance and biomass of earthworms were determined. Among the soil properties, microbial C was most strongly correlated with organic C (r=0.86, n=29). In a comparison of linear regressions between microbial biomass C and organic C for different cropping managements, the slope under bare fallow was lowest, followed by monoculture and crop rotation. The microbial: organic C ratio ranged from 1.1 to 4.3% and was significantly correlated with soil pH (r=0.66). A positive relationship between microbial C and the clay content (r=0.66) was significantly improved when soils with more than 25% clay were excluded (r=0.80). Partial correlation analysis indicated that clay had a direct influence, hardly affected by an intercorrelation with organic C. Catalase activity was highly correlated with microbial C (r=0.95) and, because a rapid and sensitive method of determination is available, was considered suitable for estimating relative amounts of active microbial biomass. A positive relationship between microbial C and the abundance of earthworms indicated interactions between microorganisms and mesofauna.
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Type of Medium: |
Electronic Resource
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URL: |