EFFECTS OF LIMING AND BORON FERTILIZATION ON MYCORRHIZAS OF PICEA-ABIES

Effects of liming and B fertilization on Norway spruce [Picea abies (L .) Karst.] mycorrhizas were studied in factorial field experiments. Th e lime was applied twice, about 30 years and 12 years before sampling (2000 and 4000 kg ha(-1) dolomite). B was applied at the rate of 1.5 k g B ha(-1) two years before sampling. Boron fertilization doubled the number of root tips in the top 10 mm of the humus layer. The proportio n of dead short root tips was increased from 10 % in control plots to 29 % in the limed plots. Numbers of dead root tips were increased when both lime and B were applied. The % of mycorrhizas with external myce lium was slightly increased and the % of Piloderma croceum Erikss. and Hjortst. was decreased by lime. In conclusion, adverse effects of lim e on mycorrhizas were found, which were ameliorated by B fertilization , but lime-induced B deficiency alone was not the only reason for the effects of lime on root mortality.