Biomass and Nutrient Cycle in Fertilized and Unfertilized Pine, Mixed Birch and Pine and Spruce Stands on a Drained Mire

Helsinki

1989

63 S.

7 Abb., 7 Tab., zahlr. Lit. Ang.

Bandaufführung

2623

36947

At the beginning of the investigation period the total biomass of the pine stands on the ordinary sedge pine mire was 48 tn/ha. The biomas of the mixed stands on the herbrich sedge pine mire was 91 tn/ha, out of which about 60% was from pine. The biomass of the spruce stands on the Vaccinium myrtillus spruce mire was 148 tn/ha. The average annual net increment of the stand biomass was 5.8 tn/ha in the unfertilized pine stand and 6.7 tn/ha in th NPK and micronutrient fertilized one during the six-year investigation period. The coresponding figures in the mixed stand were 7.2 tn/ha and 7.6 tn/ha. The net increment of the biomass in the unfertilized spruce stand was 6.9 tn/ha and in the fertilized one 8.4 tn/ha. A considerable proportion of the net increment was lost to the ground as litter in all stands. The nitrogen, phosphorus, potassium, calcium, magnesium, iron, manganese, zinc, copper and boron cycles were investigated. The annual nitrogen uptake from the soil was 26-42 kg/ha, that of phosphorus 2.5-3.4 kg/ha, potassium 4.5-12 kg/ha, calcium 12-29 kg/ha, magnesium 2-4 kg/ha, iron 1.4-6.6 kg/ha, manganese less than 2 kg/ha and the other nutrients only some grammes. Only part of the fertilizer nutrients was fixed in the stand.