Dry mass and the amounts of nutrients in understorey vegetation before and after fertilization on a drained pine bog

Silva Fennica 31(4): 391–400

Dry mass and nutrient (N, P, K, Ca, Mg, B) contents of field layer vegetation and a combination of bottom layer vegetation and litter (referred to as bottom/litter layer in the text) were studied one year before and three years after fertilization (NPK and PK) on a drained low-shrub pine bog in eastern Finland. The results of an earlier study on the tree layer were combined with those of this study in order to estimate the changes caused by fertilization in the total plant biomass and litter. Before fertilization the average dry mass of the field and bottom/litter layers was 8400 kg ha–1 and 7650 kg ha–1, respectively. The above-ground parts accounted for 25% of the total field layer biomass. The dry mass of the field and bottom/litter layers together was < 20% of the dry mass accumulated in the total plant biomass and litter. The corresponding figures for N, P, K, Ca, Mg and B were 44%, 38%, 30%, 38%, 31% and 17%, respectively. Fertilization did not significantly affect the dry mass of either the field layer vegetation or the bottom/litter layer. 33% of the applied P was accumulated in the total plant biomass and litter on the PK-fertilized plots, and 25% on the NPK-fertilized plots. For the other elements, the proportions on the PK-fertilized plots were K 31%, Ca 6%, Mg 11% and B 13%. On the NPK-fertilized plots, the corresponding figures were N 62%, K 32%, Ca 6%, Mg 9% and B 13%. Except for B and K, the accumulation of fertilizer nutrients in the understorey vegetation and litter was of the same magnitude or greater than the uptake by the tree layer.

Keywords
biomass, litter, peatland, root systems, Scots pine

Addresses
Finér, The Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, FIN-80101 Joensuu, Finland; Nieminen, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland. Fax +358 13 251 4111, E-mail leena.finer@metla.fi

Received 26 September 1996 Accepted 29 October 1997
ISSN 0037-5330

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