Abstract
Monitoring survey for acid precipitation, forest soil, and also forest decline has been carried out for five years since 1990 all over Japan. A monitoring survey site was placed at each 20km×20km. The rain water was collected for 10 days in June (rainy season). Survey of forest decline degree and soil profile were also carried out. Chemical property of rain water and soil was analyzed. In this report, the characteristics of rain water, forest soil and forest decline in Kyushu area in this period were summarized. As for pH value of rainwater, at over 80% of sampling sites the pH value showed below pH5.6. In Kyushu area the ion concentrations of Cl^-, NO_3^-, SO_4^<2-> and K^+ in rain water were lower than the average of all over Japan. The average values of soil pH in Kyushu was 5.1 and was mostly the same with the other area of Japan. The soil pH was lower in northern Kyushu than in southern Kyushu. The average concentration of exchangeable base cation (K+Ca+Mg) of soil in Kyushu was lower than that in the other area. In the case that the soil pH value was lower than pH 5.2, the concentration of exchangeable Al in soils increased with the decrease of soil pH. The decline of forest was very few in Kyushu area.
