Artikkelit jotka sisältää sanan 'Bulk density'
Estimates of carbon stores in four Northern Irish lowland raised bogs.
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Soils store more carbon (C) than does vegetation and in Northern Ireland peat has been estimated to account for about 42% of the soil C store. This estimate, however, was based on incomplete field evidence, including uncertainty on peat depths and peat bulk density. This paper aims to show how the estimate might be improved, taking into account bulk density and carbon density measurement. Trial 3-D models are presented to estimate total C content of individual bogs. Results suggest that C stores in northern Irish lowland raised bogs are lower than previously estimated primarily because of low bulk densities which showed no consistent increase with peat depth. Bulk density varied within and between bog profiles on the same bog and between bogs leading to different estimates of C stores. The research indicates a need for more precise modelling of bogs based on stratigraphy and dating of layers and a need for standardised measurement of peat bulk density and carbon storage. The findings, particularly if they apply to the extensive blanket bog, affect local and national totals of soil C stores and have implications for national policies on increasing/preserving C stores.
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Tomlinson,
School of Geography, The Queen’s University of Belfast, BT7 1NN, Northern Ireland
Sähköposti:
ei.tietoa@nn.oo
- Davidson, Sähköposti: ei.tietoa@nn.oo
Turvemaapeltojen maan ominaisuudet ja niiden vaikutus hieskoivujen alkukehitykseen Pohjois-Savossa.
English title: Soil properties of peat-based fields and their effect on the initial development of downy birch in Pohjois-Savo, southern Finland.
Avainsanat:
Bulk density;
nutrients;
downy birch;
growth disorder;
nutrient relations;
peat based field
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The present study looked into the soil properties of twenty-four peat-based field by
examining the 0-10, 10-20, 20-30 and 30-40 cm soil layers and thc effect that soil
properties have on the initial development of young stands of downy birch growing in
Pohjois-Savo, southern Finland. Adding of mineral soil to peat-based fields and the
decomposition and subsidence of peat had resulted in increasing the bulk density of the
peat, especially in the tilling layer. Also, the amounts of nutrients in the tilling layer
were higher than in the layer below. Together with fertilization, the addition of mineral
soil had increased the soil's nutrient amounts manyfold compared to virgin mires and
mires drained for forestry. Eighthy-one per cent of the trees were alive. The share of
viable trees had fallen to half of the planting density, being now just 840 trees per
hectar. The increase in the amount of extractable potassium and total copper in the soil
improved the growth of young stands and reduced the proportion of trees of inferior
quality. Growth disorders were observed in downy birch, and these were probably caused
by increases in the ratios of the amounts of main nutrients and micro-nutrients in the
soil. The ratio of nitrogen and phosphorus to copper was reflected best of all in the
growth of young stands. An increase in the amount of soil nitrogen and phosphorus in
relation to the amount of soil copper impaired stand growth and promoted the occurrence
of trees afflicted by growth disorders.
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Hynönen,
Pohjois-Savo Forestry Centre, P.O. Box 1019, FIN-70101 Kuopio, Finland
Sähköposti:
ei.tietoa@nn.oo
- Makkonen, Sähköposti: ei.tietoa@nn.oo
Metsitettyjen turvepeltojen maan fysikaaliset ominaisuudet.
English title: Physical properties of afforested former agricultural peat soils in western Finland.
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The bulk density, organic matter content and soil water-retention characteristics of twenty-one afforested former agricultural peat soils were studied. Soil samples were collected from 5-10 cm, 15-20 cm, 25-30 cm and 35-40 cm soil layers. The studied soils' physical properties differed from those of undrained peatlands and peatlands drained for forestry mainly due to the mixing of mineral soil with the peat during cultivation. In the case of thick peat soils (peat layer >30 cm), the bulk density was at a maximum (0.37 g cm-3) and the organic matter content at a minimum (54%) in the uppermost soil layer. In the case of shallow peat soils (peat layer <30 cm), bulk density increased and organic matter content decreased with increasing soil depth. In thick peat soils, total porosity and water retention at selected matric potentials were at their highest in the lowermost soil layer while in shallow peat soils, the uppermost soil layer possessed the highest total porosity and water retention. Most of the water was retained within the range -100 to -1500 kPa in both soil types. This indicated that small pores were predominant. Air-filled porosity at -10 kPa matric potential (about field capacity) was, on average, 16% in thick peat soils and 17% in shallow peat soils in the uppermost soil layer and decreased with increasing soil depth. The results suggest that the physical properties were generally rather unfavourable for adequate soil aeration and water availability as needed for satisfactory tree growth.
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Wall,
Finnish Forest Research Institute, Kannus Research Station, Box 44, FIN-69101 Kannus, Finland
Sähköposti:
ei.tietoa@nn.oo
- Heiskanen, Sähköposti: ei.tietoa@nn.oo
Turvesaannon arviointi suotyypin ja turpeen syvyyden perusteella.
English title: Estimation of peat yield of different peat deposit types.
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Preliminary regression models are produced for the estimation of dry peat yield (tons) per unit area (hectare) for different types of peat deposits with different peat thickness. The models are based on 6 500 peat samples obtained for bulk density measurements from 245 vertical peat profiles (70 virgin and drained peadands) in Finland. In general, the increase in the peat yield does not take place in 1:1 relationship with depth because average bulk density tends to decrease with peat deposit thickness. Fairly reliable estimates of the peat yield using depth and mire site type were obtained. R2 values for the eight models representing eight different groups of "mire site types" ranged from 86.0 to 95.3%.
Keywords: Bulk density, mire site types, peat deposits, peat resources
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Tolonen,
Department of Biology, University ofJoensuu, P.O. Box 111,SF-80101 Joensuu, Finland
Sähköposti:
ei.tietoa@nn.oo
- Ijäs, Sähköposti: ei.tietoa@nn.oo
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