検索画面に戻る Go Research

	(252Kb)

[C-3.1.1 Study on the effect of dry and wet acidic depositions on plants]

[Contact Person]

Nouchi Isamu
Head, Air Quality Conservation Lab.
National Institute of Agro-Environmental Sciences
Ministry of Agriculture, Forestry and Fishery
3-1-1 Kannondai, Tsukuba, Ibaraki 305 Japan
Phone +81-298-38-8161, Fax +81-298-38-8199
E-mail nouchi@ss.niaes.affrc.go.jp

[Total Budget for FY1993-1995]

14,449,000 Yen (FY1995 4,819,000 Yen)

[Abstract]

　Daily analyzed data of rain, throughfall and stemflow at a Japanese cedar stand site in mixed woods were applied to the model that determines the dry deposition by material balance at a tree canopy. The dry deposited amount of acidic matters onto the site was estimated approximately 4 times larger than wet deposited amount. In addition, the result suggested that the daily rain amount smaller than 10mm caused insufficient washing the dry deposited matter out of tree canopy.
　Another method for monitoring dry deposition using model branch made of Teflon chips was tested. The result showed linear relationship between dry deposition on model branch and that on real tree branch. However, the gradient of the linear function varied with dry deposited components.
　Relatively high concentration of H₂O₂ in fog and cloud water was observed up to about 4 ppm in central Japanese mountainous region. Some agricultural crops were exposed to simulated rain containing various concentration of H₂O₂. The results suggested that high concentration of H₂O₂, up to 100 ppm, in water would not affect the growth of plants.
　Japanese cedar seedlings were exposed to simulated acid rain. The result showed that simulated acid rain of which pH is as low as pH 2.5 had little effect on the growth of Japanese cedar seedlings and cation leaching from the seedlings was increased by simulated acid rain of which pH is 3.0 or lower, compared with that in the case of pH 5.6.

[Key Words]

Dry Deposition, Woods, Hydrogen Peroxide, Leaching