[H-TT23] [JJ] 環境トレーサビリティー手法の開発と適用

[HTT23-11] スギの地理変異が土壌生態系に与える影響は大きく異なる

*太田 民久¹、日浦 勉² (1.総合地球環境学研究所、2.北海道大学)

キーワード：Cryptomeria japonica、Rhizosphere

Soil organisms can be affected by differences in aboveground vegetation, often driven by the chemical quality of the soil and litter. C. japonica is the most popular plantation tree species in Japan, and plantations of C. japonica account for 12% of the total land area in Japan. C. Japonica has many geographic variations such as Yakusugi and Yoshinosugi, and has been planted at each provinances. Our previous studies showed plantation of C. japonica affect community structure of soil invertebrate by altering calcium availability in soil. However, we have not estimated whether the effects of plantation on soil organisms vary depend on the geographic variation. In Wakayama Experimental Forest, Hokkaido University, there are common gardens that planted various provenances of C. japonica. We investigated the soil solution and leaf litter chemistry, root exudation rates of organic acids and soil invertebrate community, and we compared between plots that planted a different provenances of C. japonica (Yakusugi, Yanasesugi, Yoshinosugi and Itoshirosugi). Our results showed the diversity of soil invertebrate and concentrations of essential nutrients (calcium and phosphorus) in soil and litter significantly higher at the plot where native provenance, Yoshinosugi, was planted. Furthermore, root exudation rates of organic acids were also significantly higher at the plot where Yoshinosugi was planted. Supply of the organic acids from root systems of tree can alter dynamics of soil nutrients. Therefore, variation of rhizosphere environment might create differences in soil nutrients availability and soil invertebrate community.