模擬酸雨對杉木及樟樹苗木生長與養分淋溶之影響

The Effects of Simulated Acid Rain on the Growth and Nutrients Leaching of China-fir and Camphor Tree Seedlings

藉由模擬酸雨處理杉木及樟樹苗木，以探討酸雨對苗木生長、離子淋溶、組織養分含量之影響。模擬酸雨是以SO42-與NO3-當量濃度比3：1之比例混合，調整pH值至5.6，4.1和2.6，分別處理杉木16週、樟樹12週。試驗結果顯示苗木在低pH（pH2.6）處理下，二樹種的地徑、苗高、乾重和葉面積皆下降，而Ph4.1對杉木反而有施肥的功效，其苗高淨生長、乾重和葉面積有增加的情形。酸雨流經冠層後之穿落水可淋溶出陽離子及陰離子，其中大部分的陽離子及SO42-濃度均隨著雨水酸度的增加而增加。樟樹對H+之中和能力較杉木大。杉木冠層對NO3-則有吸收的作用。雖然部分離子之淋溶情形有些差異，然仍可應證野外之調查結果。 The seedlings or China-fir (Cunninghamia lanceolata) and Camphor Tree (Cinnamomum Camphora) were treated with simulated acid rain, in order to understand whether seedling growth, ions leaching, and nutrient content in tissues were affected. Simulated acid rain was a mixture of 3:1 equivalent concentration ratio of nitric and sulfuric acid. The pH value was dilute with water to 5.6, 4.1, or 2.6. The seedlings of these two species were treated for 16 weeks and 12 weeks, respectively. Seedling diameter, seedling height, total biomass and leaf area of these two species decreased significantly under grown in pH 2.6. The seedlings of China-nr treated with moderately acid rain (pH 4.1) had a greater net seedling height growth, total biomass, and leaf area resulting from fertilizer (N) effect. Most of the ion concentrations in throughfall had higher values. It indicated that acid rain passing through the canopy of these two species could leach or wash off some cations and anions. In addition, there was a trend toward increasing the concentration of most cations and SO42- in throughfall with the increasing of rain acidity. The capacity of neutralizing acid deposition was more eflicien1 for Camphor Tree leaves than for China-fir. Although there were a little different of ion leaching phenomena, this experiment also did be able to prove the field investigation.

The seedlings or China-fir (Cunninghamia lanceolata) and Camphor Tree (Cinnamomum Camphora) were treated with simulated acid rain, in order to understand whether seedling growth, ions leaching, and nutrient content in tissues were affected. Simulated acid rain was a mixture of 3:1 equivalent concentration ratio of nitric and sulfuric acid. The pH value was dilute with water to 5.6, 4.1, or 2.6. The seedlings of these two species were treated for 16 weeks and 12 weeks, respectively. Seedling diameter, seedling height, total biomass and leaf area of these two species decreased significantly under grown in pH 2.6. The seedlings of China-nr treated with moderately acid rain (pH 4.1) had a greater net seedling height growth, total biomass, and leaf area resulting from fertilizer (N) effect. Most of the ion concentrations in throughfall had higher values. It indicated that acid rain passing through the canopy of these two species could leach or wash off some cations and anions. In addition, there was a trend toward increasing the concentration of most cations and SO42- in throughfall with the increasing of rain acidity. The capacity of neutralizing acid deposition was more eflicien1 for Camphor Tree leaves than for China-fir. Although there were a little different of ion leaching phenomena, this experiment also did be able to prove the field investigation.