EFFECTS OF MYCORRHIZAL INOCULATION AND FERTILIZER REGIME ON EMERGENCEOF SITKA SPRUCE SEEDLINGS IN BARE-ROOT NURSERY SEEDBEDS

Seedbeds at two Scottish nurseries (Forfar and Newton) were inoculated with the ectomycorrhizal fungus Laccaria proxima (Boud.) Pat. and sow n with Sitka spruce (Picea sitchensis (Bong.) Carr.) seed. Numbers of emergent seedlings were affected by both inoculum and fertilizer treat ments. Up to 114% more seedlings were found in plots inoculated with l ive fungus in a vermiculite-peat carrier than in control plots with or without the same carrier. A similar, although reduced, effect was fou nd when the live fungus was encapsulated in alginate beads. Applicatio n of fertilizer (to the seedbed before sowing and subsequently as a to p dressing) reduced numbers of emergent seedlings at both nurseries; a t Forfar, numbers in the treatments that had received fertilizer were 40-50% of the numbers in the analogous unfertilized treatments, while at Newton, the plots that had received live inoculum and fertilizer co ntained seedling numbers that were 66-72% of those in the comparable u nfertilized treatment. The effect of inoculant on seedling numbers occ urred within the first few weeks after inoculation and was independent of mycorrhizal formation.