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Temporal changes in organic carbon of soils developed on volcanic andesitic deposits in Japan

2002; Elsevier BV; Volume: 171; Issue: 1-2 Linguagem: Inglês

10.1016/s0378-1127(02)00465-6

1872-7042

Kazuhito Morisada, Akihiro Imaya, Kenji Ono,

Geochemistry and Geologic Mapping

Temporal changes in organic C stock with soil development were assessed by determining organic C stocks in soils on new deposits of andesitic volcanic materials of different ages. The soils included in this study have developed on avalanche debris of 91-year-old at Bandai, 197-year-old at Asama Kanbara, and 1110-year-old at Yatsugatake. Soils at Asama Oiwake had developed on 849-year-old material from pyroclastic flow. All the soils were located in montane zone and had similar cool temperate and humid climate. Organic C in these soils increased with soil age and therefore also in soil depth. However, organic C concentration in the surface 0–10 cm soil varied among sites independent of their age (5.3% in Bandai, 3.4% in Asama Kanbara, 5.5% in Asama Oiwake, and 12.5% in Yatsugatake). The organic C concentration in the surface 0–10 cm depth at Yatsugatake site was similar in the soil developed from the new deposits to that developed in an adjacent area under much older deposit. Organic C contents in 0–100 cm soil depth were: 53±29 t ha−1 (n=11) at Bandai, 55 t ha−1 at Asama Kanbara, 85±18 t ha−1 (n=2) at Asama Oiwake, and 127±36 t ha−1 (n=3) at Yatsugatake sites. Almost half of the organic C in the 0–100 cm depth was present in the surface 10 cm depth. Organic C content in soils on the new deposits was much lower than in those of the adjacent area with much older deposits. Soil organic C at Yatsugatake site maybe approaching a steady-state condition which was supported by the presence of immature soil humic acids in it. Rate of organic C accumulation declined with soil age, with a rapid increase of organic matter occurring during early stages of soil development. Accumulation rates of organic C were 0.10 t ha−1 per year at Asama Oiwake and 0.11 t ha−1 per year at Yatsugatake sites, and these rates were comparable with those reported as maximum values in the literature.