[M-IS03] Wetland ecosystems under pressure, impacts on the environment and social activities

[MIS03-P02] Changes in peat soil properties adjacent to eroded lands in the Komado wetland

*川東 正幸¹、Payandi-Rolland Dahedrey¹、谷口 柊¹ (1.東京都立大学)

キーワード：駒止湿原、深層泥炭、土壌侵食、酸化還元

The Komado wetland is the specially protected area designated by Japanese government. However, the surrounding areas of the wetland have been reclaimed to develop agricultural areas. During the management for agriculture in the surrounding areas, mineral soils were invaded into the wetland in the late 1980’s. The effects of mineral intrusion into the wetland were not well detected through soil analyses. In this study, peat soils reaching to over 1 m depth were collected from the center and the edge of the wetland to analyze general soil properties to confirm the influences of mineral soil contamination flow from the degraded previous farmlands. Peat soils collected from the center position in the wetland were characterized by relatively high C/N ratio with low ash contents. At the edge of the wetland, the C/N ratio of the peat soils were almost half from those in the center of the wetland, indicating that the accumulated plant debris at the end of the wetland has been biologically decomposed to decrease the C/N ratio. The high C/N of peat soils in the center decreased with depth according to its decomposition. Although deep peat soils were saturated with underground water whole through years, surface peat soils have been seasonally aerated and accumulated iron oxides. Calcium was also similar distribution with iron with depth, indicating that early stages of decomposition of plant debris promoted accumulation of those minerals. Vertical distribution in sulfur was also characteristic with peat decomposition probably affected by the mineral soil intrusion.