Artikkelit kirjoittajalta Antti Wall
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
Metsitettyjen turvepeltojen ja viereisten suometsien ravinnemäärät.
English title: Nutrient amounts of afforested peat fields and neighbouring peatland forests.
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Chemical and physical characteristics of afforested peat fields were compared with those of neighbouring peatland forests, i.e. naturally forested peatland sites drained to improve forest growth. Six study sites were selected with such sites located alongside an afforested peat field. On three of the fields, mineral soil had been added during cultivation as a soil amelioration agent. Most of the fields had been cultivated for 15–20 years before afforestation. Volumetric soil samples were taken and analysed for their total and ammonium acetate extractable nutrient concentrations (P, K, Ca, Mg, Mn, Fe, Zn). Kjeldahl N and B in H3PO4–H2SO4 were also analysed. The soil layers 0–20 cm (the field cultivation depth) and 20–40 cm were compared. The physical and chemical characteristics of the top soil in peat fields and neighbouring forests differed in many respects even after 25 years had passed since their afforestation. Bulk density, ash content and pH of the peat were higher in the cultivation layer of the fields than in the corresponding layer in peatland forests. In cases where mineral soil had been added to the peat fields, the amounts of P, K, Ca, Mn and Zn were higher in the 0–20 cm soil layer whereas the amounts of N and B did not significantly differ from those in the soils of peatland forests. The differences in the amounts of extractable nutrients between the field soils and forests soils were smaller; Ca and (when mineral soil had been added) also Fe and Zn concentrations were higher in the peat field soils than in the soils of peatland forests.
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Hytönen,
The Finnish Forest Research Institute, Kannus Research Station, P.O.Box 44, FIN-69101 Kannus, Finland
Sähköposti:
ei.tietoa@nn.oo
- Wall, Sähköposti: ei.tietoa@nn.oo
Painomaan vaikutus metsitetyn turvepellon ravinnemääriin.
English title: Effect of mineral soil admixture on the nutrient amounts of afforested peat fields.
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The effect of mineral soil, applied during the cultivation of fields, on the nutrient amounts of afforested peat fields was studied. 36 afforested peat fields (peat layer>40 cm) from Central Ostrobothnia (western Finland) and North Savo (central Finland) were sampled. Fields were divided into two groups on the basis of mineral soil addition. Volumetric soil samples (0-10, 10-20, 20-30, 30-40 cm layers) were taken and and analyzed for their total and ammonium acetate extractable nutrient concentrations (P, K, Ca, Mg, Mn, Fe, Zn). Kjeldahl nitrogen and boron in H3PO4-H2SO4 were also analyzed. Nutrient amounts in different soil layers were calculated. Mineral soil, mainly silt, had been added on average 230 m3ha-1 in Central Ostrobothnia and 630 m3ha-1 in North Savo. Mineral soil was clearly detectable in the plough layer (0-20 cm) but seldom in the 30-40 cm layer as an increased bulk density and ash content. Mineral soil admixture increased most of the total nutrient amounts, but not nitrogen, calcium and boron. In the amounts of extractable nutrients the effect of mineral soil admixture was smaller.
Key words: afforestation, mineral soil, nutrition, peat fields
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Wall,
The Finnish Forest Research Institute, Kannus Research Station, P.O.Box 44, FIN-69101 Kannus, Finland
Sähköposti:
ei.tietoa@nn.oo
- Hytönen, Sähköposti: ei.tietoa@nn.oo
Uuttoajan ja EDTA:n vaikutus metsitettyjen peltomaiden ravinteiden uuttumiseen happamaan ammoniumasetaattiin.
English title: Effect of extraction time and EDTA on acid ammonium extractable nutrient concentrations of afforested agricultural soils.
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The effect of extraction time on the extraction of P, K, Ca, Mg and the effect of EDTA on the extraction of Mn, Fe and Zn with acid ammonium acetate was studied in 196 soil samples collected from afforested agricultural soils. Extraction time (1 hour or ca. 20 hours) did not significantly affect gravimetrically expressed mean concentrations of K, Ca and Mg in mineral soil samples. In peat samples the mean concentration of Ca and Mg with the shorter extraction time was 73% and 81% respectively of the mean concentration obtained with longer extraction time. The mean concentration of P with the extraction time of 1 hour was about 50% of the mean concentration obtained with the longer extraction time in peat and mineral soil samples. Extraction with acid ammonium acetate/EDTA extracted Fe sevenfold and Zn almost threefold compared with acid ammonium acetate alone. Regression models for converting gravimetric and volumetric nutrient values obtained with methods used in agriculture to gravimetric and volumetric nutrient values obtained with methods used in forestry are presented.
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Wall,
The Finnish Forest Research Institute, Kannus Research Station, P.O.Box 44, FIN-69101 Kannus, Finland
Sähköposti:
ei.tietoa@nn.oo
- Urvas, Sähköposti: ei.tietoa@nn.oo
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