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Soil microbial biomass, activities and diversity in Southern Italy areas chronically exposed to trace element input from industrial and agricultural activities
No full textHigh concentrations of trace elements in the soil can have toxic effects on the microbial community which plays a
key role in fundamental ecosystem processes like the organic matter decomposition and nutrient cycles. The aim
of this study was to evaluate if trace element concentrations in soils chronically exposed to industrial and
agricultural activities did affect the soil microbial community, in terms of biomass, activity and diversity. Soil
samples differing in trace elements (As, Cd, Co, Cr, Cu, Ni, Pb, V, Zn) concentrations were analysed for the total
microbial biomass (Cmic), fungal mycelium, microbial activity, indexes of microbial community structure (fungal
percentage of total Cmic) and microbial metabolism (metabolic quotient or qCO2; carbon mineralization rate or
CMR), and genetic bacterial diversity (richness, Shannon index and evenness of bacterial groups). Relationships
of the microbial variables with individual trace element concentrations, relative Overall Contamination Index
(OCI), and ordinary soil properties (pH, water content, organic C content, electrical conductivity) were assessed
by simple and multivariate statistical analysis. Neither OCI nor single element concentrations determined a
significant reduction in soil microbial biomass, activity and diversity, these variables being mainly driven by soil
organic C and water content. Only soil Cr concentration affected indexes of the microbial metabolism and
structure, without causing stressful conditions. Even Cmic and bacterial diversity showed higher values in soils
richer of Cr. The results suggest that the concentrations of considered trace elements measured in our soils, or
probably their bioavailable fractions, did not cause toxic effects on the microbial community. However, the
chronic exposure to different patterns of trace element contamination probably elicited site-specific adaptive
responses in microbial populations
Soil microbial metabolism and nutrient status in a Mediterranean area as affected by plant cover.
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Nutrient dynamics in decaying leaves of Fagus sylvatica L. and needles of Abies alba Mill.
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Grazing impact on soil chemical and biological properties under different plant cover types in a mountain area of Southern Italy.
Full text linkGrazing can contribute to soil degradation by compaction due to roaming of livestock and loss of herbaceous cover, affecting also soil microbial community. Aim of this study was to assess grazing impact on soil microbial community and nutrient status under different plant cover types (i.e., fernery, chestnut wood, garigue). Grazed and ungrazed soils were analysed for water holding capacity, pH, organic carbon, N, S, K, Mg, Fe, Mn, Zn and Cu content, microbial biomass, fungal mycelium and potential respiration. Moreover, some ecophysiological indices, as microbial quotient, coefficient of endogenous mineralization (CEM), metabolic quotient (qCO2) and fungal fraction of microbial carbon were calculated. The results of present study showed that a moderate intensity grazing had low or no impact on chemical characteristics of soils and affects microbial community mainly in grazed areas with lower vegetation cover and lower content of nutrient and organic carbon, compared to areas with a thick layer of vegetation
Nutrient dynamics in decaying leaves of Fagus sylvatica L. and needles of Abies alba Mill.
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