Biomorph silica in meadow soils of the Mid-Amur lowland

On the basis of an analysis of the gross composition and morphology of the particles of soil samples from the Mid-Amur lowlands, it is shown that the biomorph silica of the meadow soils with bleached horizons is represented by meadow forms of phytoliths (mainly true grasses). In the upper profile part of the AUg horizon, frustules of diatom algae are found, while no spicules of sponges are registered. The upper part of the profile is characterized by the highest degree of weathering of the phytolith silica. In the lower part, they are better preserved. In this part of the profile, diatoms are represented by small-celled species around 2 μm in size (supposedly, spores of Cyclotella sp.). The presence of such algae in the water-peptized silt is associated with the process of migration down the profile.