ФНЦ Биоразнообразия ДВО РАН

Diversity of Andisols on the Kamchatka Peninsula

Shlyakhov S.A.

Andisols are located directly in the places of recent volcanic activity along the eastern coast of the Kamchatka peninsula are studied. Significant amounts of volcanic ejecta (ash, pumice, cinders etc.) fall repeatedly on the surface of the soils from the atmosphere. Therefore, marks of pedogenesis in their profiles are expressed less than the lithological stratification. In the Russian soil classification such substrata named as volcanic ash stratified soils. In 1998 the two locations were studied: 1) area near Karymskiy volcano; 2) Tolbachik Dol related to the Kluchevskaya volcanic group. Andisols found close to volcano Karymskiy consist of the layers of igneous material (black and light-gray to whitish) and buried O and A horizons. Bottom parts of soils have typical grayish-brown color, which disguise soil’s stratification. The morphological properties permit to distinguish Andisols of tundra, meadow, Pinus pumila and dwarf alder thickets, wetlands (near Karymskaya river), young lava flows with primary vegetation and geothermal fields (with active geysers). The last kind of soils is differed from other soils of this territory by much finer texture, much lesser expressed stratification and uniform color of profile. In terms of Soil Taxonomy most pedons are Cryands with the exceptions of Andisols with aquic conditions (Aquands) and soils of geothermal sites. In the Tolbachik Dol soil pits were opened in several sites along a transect between the North Vent and the South Vent of the split eruption 1975 - 1976. Larch forest occupied this territory recently. It was partly exterminated, partly damaged by the eruption. Forests soils were buried by tephra. Examined soils consist of layers of igneous material (black and light-gray to whitish) and buried A and AC horizons. The thickness of the surface tephra layer decreases southward from 238 to 20 cm. Soils on young lava have very simple profile structure. AC horizon underlied by lava boulders occurs beneath the recent cinder layer.