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Tekijät
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
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Makkonen,
Sähköposti:
ei.tietoa@nn.oo
