| Abstract: | Scots pine (Pinus sylvestris) seedlings were planted in a nursery bed 20 cm thick. The substrate had been removed from an illuvial horizon in the soil underlying a stand of Scots pine in Finland, which had suffered from severe infection by Gremmeniella abietina. The seedlings were irrigated for 3 years, applying three pH levels (2.5, 3.5, and 4.5) using sulphuric acid, nitric acid, and a 3:1 mixture of sulphuric and nitric acid. The pH of the pure water used in the control treatment was 6.1–6.4. The seedlings were inoculated with the conidiospores of G. abietina to find out their susceptibility to infection with the Scleroderris canker disease. Because to the adequacy of its buffering capacity, the soil was observed to become more acidic only in the treatments at pH 2.5. The concentrations of extractable Ca and Mg cations decreased while the concentration of Al and Fe increased with soil acidification during the 3-year experiment. Acidification did not increase the susceptibility of Scots pine to infection by the Scleroderris canker. Seedling growth was at its maximum in the acidification treatments where most nitrogen was added. |
