Current issue: 56(4)
The aim of the study was to assess the contents and quantities of macronutrients reaching the ground with precipitation, stemflow and throughfall in Scots pine (Pinus sylvestris L.) stands growing on drained peatland, one of which was unfertilized and two of which had been fertilized three growing seasons before the measurements were carried out.
According to the results, the quantities of nutrients reaching the ground with precipitation were relatively large as compared, for example, with those removed with the stem wood carried away from the forest in logging. The nutrient most exposed to leaching from the canopy is potassium. Both the content of potassium in rainwater penetrating the canopy and the quantities reaching the ground are highest in stemflow, decreasing when moving from under the tree crowns toward the edge of the crown projection and into openings in the canopy. The results for phosphorus were similar, although not as clear as for potassium.
The contents of NO3-N were smaller in stemflow than in precipitation. The results did not support assumptions according to which nitrate nitrogen is leached from the canopy or is taken up by the canopy from precipitation. In the case both of precipitation and of throughfall and stemflow, the quantities of nitrite nitrogen recorded were smaller than the degree of precision applied in the determinations carried out (0.01 mg/1). The contents of NH4-N were on average higher in stemflow and throughfall than in precipitation.
Fertilizer application (600 kg/ha of N-P2O5-K2O, 14-18-10) increased the contents of potassium in stemflow and throughfall. A slight increase in phosphorus was also observed. Leaching of inorganic nitrogen was not affected by fertilization.
The PDF includes a summary in Finnish.