Polokhin O.V.
Scientific Review. Biological science 2017; (5): 18-22
The results of studying volcanic soils in the central part of the island of Urup (southern Kurile Islands) were presented. Registration sites – on a sea terrace with coastal vegetation and on the steeply sloping surface of the Rudakov Mountain under arboreal and shrubby meadow vegetation were laid. The structure of the profiles and the morphological features of soils are shown. It was established that each plant association corresponds to a certain type of soil. On the sea terrace, there are sod-layered sandy soils, and on the slope there are soddy-humic medium-thick volcanic soils. Soils on steeply sloping surfaces have a shortened profile with sharply increasing stony down the profile. The absence of visible layers of ash, the presence of buried horizons testifies to the long-standing large eruptions of the volcano Rudakova and the study area has been in the zone of weak ash falls for a long time. The morphological structure of the soil profile of sod-humus volcanic soils confirms that soil formation has a synlithogenic (volcanogenic) character. According to the values of the actual acidity, they can be attributed to soils with acidic (medium-acid) reaction of the medium. The acid-base properties of soils on the slopes depend to a large extent on the biogenic and climatogenic factors. In terms of the actual acidity, these soil soils are acid-nondifferentiated. Sod-layered sandy soils have higher pHH2O values than sod-humus soils and correspond to soils with medium reaction from weakly acidic to near neutral. It can be assumed that the actual acidity of the soils of the sea terrace depends on the distance from the waters of the Sea of Okhotsk.
