Growth of Pinus sylvestris after the application of wood ash or P and K fertilizer to a peatland in southern Sweden
2010
Sikström, Ulf | Almqvist, Curt | Jansson, Gunnar
The effects of the application of wood ash and of fertilizer regimes including phosphorus (P) and potassium (K), with and without simultaneous addition of nitrogen (N), were investigated on a stand of Scots pine (Pinus sylvestris L.) saplings growing on a drained oligotrophic peatland site in southern Sweden. A randomized block design was used. Tree growth and concentrations of various elements in the needles were measured. The addition of similar doses of P (approx. 40 kg P ha) from different sources resulted in similar growth responses, amounting to 1.6â1.9 m ha yr of stem wood over the 26-year study. The P source was either wood ash (2500 kg d.w. ha) or PK-fertilizer (raw phosphate and potassium chloride). In response to several treatments there were both increased numbers of trees and increased growth of individual trees. The high PK-dose (40 kg P ha and 80 kg K ha) appeared to result in a larger growth increase than the low dose (20 kg P ha and 40 kg K ha). The N treatment had no additional effect on growth. In the control plots, tree growth was more or less negligible (0.04 m ha yr). After almost 26 years, concentrations of P and K in the needles of treated plants were still higher than in the untreated control plants. Nevertheless, in spite of the elevated P concentration, P appears to limit the growth of Scots pine. In conclusion, after sufficient drainage of this type of peatland site, it is possible for a forest stand to develop to the pole stage if wood ash or PK-fertilizer is applied.â13â1â1â1â1â1â1â13â1â1
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