EFFECTS OF FERTILIZATION, LIMING, WATERING AND TILLAGE ON PLANT COLONIZATION OF BARE PEAT SURFACES

Two field experiments exploring plant colonization of bare peat surfac es were conducted at two adjacent peat harvesting sites in Finland, di ffering markedly in natural rate and pattern of revegetation and in su bstrate quality. The first experiment examined the effects of light NP K fertilization, liming and watering and the other the effect of tilli ng of the surface peat layer. The amount of vegetation established was greater in all plots at the site with higher natural rate of revegeta tion. Fertilization, both alone and in interaction with the site, had significant effects on the biomass and composition of the established vegetation. At both sites, the fertilized plots differed significantly from all other plots in biomass and in species composition of the est ablished vegetation. Epilobium angustifolium was the dominant species in the fertilized plots and almost absent from the unfertilized plots. At the site with higher natural rate of revegetation, the fertilized plots also differed strikingly from the unfertilized plots in quantity of several other species. Liming had no effect on the above-ground bi omass of vegetation at the site with the higher natural rate of revege tation, but had a significant effect at the other site. Light watering did not have a major effect on plant colonization at either site. In the first summer, tilling of the uppermost peat layer had no effect on the number of established plants, but at the end of the second growin g season, at both sites, a significantly larger number of seedlings ha d established in the tilled plots.