Antti Wall , Juha Heiskanen

Metsitettyjen turvepeltojen maan fysikaaliset ominaisuudet

Wall A., Heiskanen J. Metsitettyjen turvepeltojen maan fysikaaliset ominaisuudet.

Tiivistelmä

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.

Avainsanat
Bulk density; organic matter; water retention; peat fields; soil aeration

Vastaanotettu 31.10.2017 Julkaistu 1.1.1998

Katselukerrat 1335

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