Artikkelit jotka sisältää sanan 'organic matter'

Antti Wall, Juha Heiskanen. Metsitettyjen turvepeltojen maan fysikaaliset ominaisuudet.
English title: Physical properties of afforested former agricultural peat soils in western Finland.
Avainsanat: Bulk density; organic matter; water retention; peat fields; soil aeration
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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.
  • Wall, Finnish Forest Research Institute, Kannus Research Station, Box 44, FIN-69101 Kannus, Finland Sähköposti: ei.tietoa@nn.oo (sähköposti)
  • Heiskanen, Sähköposti: ei.tietoa@nn.oo
Carl C. Trettin, Margaret R. Gale, Martin F. Jurgensen, James W. McLaughlin. Carbon storage response to harvesting and site preparation in a forested mire in northern Michigan, U.S.A.
Avainsanat: Decomposition; organic matter; site preparation; whole-tree harvest
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This study considered the effects on carbon pools in a forested mire following whole-tree harvesting and two site preparation treatments; bedding and trenching. Whole-tree harvesting, which resulted in complete removal of the overstory biomass, and bedding exhibited the greatest loss of carbon from the site. Removal of the overstory biomass and increased decomposition of organic matter were the major causes of carbon loss. Measurement of the soil carbon pools in the tree planting zone did not provide an accurate assessment of the treatment effect. Renewal of carbon accumulation will depend on the productivity and composition of the regenerating plant community and on the rate of decomposition of organic matter. Keywords: Decomposition, organic matter, site preparation, whole-tree harvest
  • Trettin, Environmental Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008 MS-6038, Oak Ridge, 77V 37831-6038 U.S.A Sähköposti: ei.tietoa@nn.oo (sähköposti)
  • Gale, Sähköposti: ei.tietoa@nn.oo
  • Jurgensen, Sähköposti: ei.tietoa@nn.oo
  • McLaughlin, Sähköposti: ei.tietoa@nn.oo
Kimmo Tolonen, Harri Vasander, Antoni H. Damman, R. S. Clymo. Preliminary estimate of long-term carbon accumulation and loss in 25 boreal peatlands.
Avainsanat: Climatic change; organic matter; stratigraphy
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The rate of carbon accumulation (RCA) was studied stratigraphically in individual vertical cores representing 25 mires in Finland, Estonia and Maine, USA. Carbon 14-datings (325 in total) were used for dating long cores encompassing all or most of the Holocene. The apparent long-term RCA (g m-2 a-1) in Finnish raised bogs and fens ranged from 13 to 41 and from 8 to 25, respectively, and in Maine bogs from 20 to 26 and in a single fen 27. Between and within core variations were great. In Finnish mires the true RCA, as derived from Clymo's peat accumulation model for long cores, was usually about 2/3 of the apparent long-term RCA. A change from intensive decay in the surface layers to very slow decay in deeper peat layers was dated to between some 300-500 years ago. Key words: Climatic change, organic matter, stratigraphy
  • Tolonen, Department of Biology, University of Joensuu, P.O. Box III, FIN-80I01, Finland Sähköposti: ei.tietoa@nn.oo (sähköposti)
  • Vasander, Sähköposti: ei.tietoa@nn.oo
  • Damman, Sähköposti: ei.tietoa@nn.oo
  • Clymo, Sähköposti: ei.tietoa@nn.oo

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