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 (328Kb)
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14,253,000 Yen (FY1995; 4,888,000)
The condition around coniferous trees in the soil is becoming gradually acidic when acid rain falls continuously. Nutrient uptake by the roots of coniferous trees could be affected in such environmental change of rooting zone. The experiments of water culture of coniferous seedlings in modified systems were carried out using 2- and, 3-year-old Japanese cedar(Cryptomeria japonica), Japanese cypress(Chamaecyparis obtusa), and red pine(Pinus densiflora) that are the typical Japanese forest trees. Nine major nutrients such as Na+ , NH4+, K+, Ca2+, Mg2+, Cl-, N03-, PO43-, and SO42-, were given in the water culture solution and growth of trees was observed for three years. The aspects of nutrient uptake by these seedlings and the effects of acidity in culture solution were observed. The following results were obtained. 1)Japanese cedar of 50%, Japanese cypress of 30%, and red pine of 40% in tested seedlings could live for two years. 2)All seedlings,Japanese cedar, cypress, and red pine, that started in the strong acidic condition (pH=3.0) were dead within three months. 3)The minimum pH value in the acidic condition that seedlings can live for two years is estimated as 3.2. 4)The seasonal pattern of the uptake of nitrogen nutrient by Japanese cedar was determined. 5)We offer a hypothesis that coniferous trees have a buffering mechanism against acidification around rooting zone. 6)We found that excess load of nitrate ion in culture solution disturb the avility taking up water from their roots of seedling.
Water Culture, Japanese Cedar, Japanese Cypress, Red Pine, Acidic Effects