Artikkelit jotka sisältää sanan 'substrate'
Kasvualustana käytetyn heikosti maatuneen rahkataturpeen lämmönjohtavuus.
English title: Thermal conductivity of low-decomposed Sphagnum peat used as growth medium.
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The thermal conductivity of low-decomposed Sphagnum peat, used as a growth medium for container seedling production in tree nurseries, and of a sandy mineral soil was studied using the single thermal probe method in the laboratory. The thermal conductivity of the peat was low and decreased from 0.5 to 0.05 W m-1K-1 when the water content decreased from near saturation to air-dry. In comparison, the thermal conductivity of the sandy soil was much higher, decreasing steeply from 1.5 to 0.5 W m-1K-1 with decreasing water content. Results are in accordance with those reported earlier for similar media. The results suggest markedly weaker and more delayed temperature fluctuations in pure peat media compared with media containing mineral soil, which is in agreement with observations made in tree nurseries.
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Heiskanen,
Finnish Forest Research Institute, Juntintie 40. FIN-77600 Suonenjoki, Finland
Sähköposti:
ei.tietoa@nn.oo
Turvepohjaisten kasvualustojen tiivistyminen yksivuotisessa paakkutaimikasvatuksessa.
English title: Compaction of growth media based on Sphagnum peat during one-year culturing of container seedlings.
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Changes in bulk density and water retention during one-year culturing of container seedlings were studied in pure, low-humified Sphagnum peat and in peat-based two-component growth media. In all growth media, the bulk density increased slightly with time. The corresponding decrease in total porosity was negligible (< 1 %-unit for pure peat). At matric potentials < -1 kPa, water retention of growth media tended to increase somewhat with time. On the other hand, shrinkage at desorption decreased during seedling culturing. The results suggest that, from the standpoint of seedling growth, the structure of growth media based on Sphagnum peat does not markedly change or deteriorate during one-year culturing of seedlings. However, in seedling culturing peat growth media containing hydrogel may possess restricted aeration due to excess water retention, while addition of coarse textured materials, such as perlite, to peat can increase aeration.
Key words: nursery management, soil physical properties, shrinkage, substrate, water retention
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Heiskanen,
The Finnish Forest Research Institute, Suonenjoki Research Station, FIN-77600 Suonenjoki, Finland
Sähköposti:
ei.tietoa@nn.oo
Metsäteollisuuden bioliete ja kivihiilen tuhka rauduskoivun taimien ravinnelahteenä.
English title: Pulp biosludge and coal ash as nutrient sources for silver birch seedlings.
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Biosludge from a biological waste-water treatment plant was tested in a greenhouse experiment on three substrates at 7 levels (0-240 m3/ha). The growth of birch seedlings was best on nitrogen poor substrate collected from a Vaccinium vitis-idaea (VT) forest site. NPK-fertilization was superior to sludge treatments on poor peat substrate. Biosludge increased the foliar nitrogen content on all three soils. Nutritional value of coal ash was tested at 17 levels (0.4-160 t/ha) on mineral soil from an afforested field. Low application levels of coal ash (400-1600 kg/ha) increased the growth of the birch seedlings more than other applications. However, even extremely high coal ash amounts (up to 160 t/ha) were not lethal for birch seedlings. Coal ash increased foliar boron contents two to three fold and with applications higher than 20 t/ha increase was five to seven fold. Birches planted in 1978 on a coal ash landfilling area showed good survival and growth, despite toxic boron contents and visual disturbances in the leaves.
Key words: Boron toxicity, fertilization, peat substrate, recycling
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Veijalainen,
The Finnish Forest Research Institute, Box 18, FIN-01301 Vantaa
Sähköposti:
ei.tietoa@nn.oo
- Silfverberg, Sähköposti: ei.tietoa@nn.oo
- Hytönen, Sähköposti: ei.tietoa@nn.oo
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