| Popis: |
AimsPlant cover and microclimatic conditions can profoundly alter the balance between productivity and decay, with relevant effects on soil C and N pools. In this contest, the aim of the present study was to assess how, in Mediterranean areas, soil properties and C and N sequestration differs between afforested pine forests and natural shrublands in different microclimatic conditions at low and high elevations.MethodsThe study was performed along the soil profile distinguishing between the organic layers, fermentation and humic layers, and surface mineral soils. The comparison between plant covers and elevations were carried out for C and N pools and soluble fractions, molecular characterization by solid state 13C NMR of organic layers and by 1HNMR of soil soluble fractions, potential mineralization rates and microbial and fungal amounts.ResultsOur data confirm that coniferous tree species sequester C faster than shrubs and herbaceous species especially at low elevation under favourable microclimatic conditions. Soil C and N pools reflect changes in the chemical composition of the upper organic layers and of soil soluble organic matter. In pine forests, the higher concentration of N in the upper organic layer speeds up the N loss in the fermentative layer and stimulates humus formation and C accumulation at low elevations.ConclusionsPlant cover and microclimatic conditions drive the C sequestration rate and the soil organic matter stability. Chemical changes highlighted by nuclear magnetic resonance spectroscopy can clarify patterns of decay processes and help to make predictions in a climate change scenario. |
