Органическое вещество гранулометрических фракций и его роль в формировании морфогенетического своеобразия буроземов острова Русский

Abstract

The features of the fixation of humus substances by particle-size fractions of soil for the main types of burozems of the Russky Island are characterized. It is shown that the diagnostic indicator of the morphological diversity of island burozems soils, reflecting the different intensity of the development of accumulative-humus and illuvial-humus processes of soil formation in their profile, is the level of carbon accumulation in the fractions of silt and fine dust, the share of carbon of these fractions in the structure of the total humus and the features of its profile dynamics. It has been established that in typical burozem, the bulk of carbon is confined to the fraction of silt, with depth the role of silt in fixing the organic matter of these soils only increases. In dark burozem, the carbon content of the silty fraction increases almost twice as compared to typical brown soils, and its share in the composition of total soil carbon decreases. At the same time, the saturation of the organic matter of the upper humus horizon with carbon of the fine dust fraction increases. The most significant changes in the structure of total carbon and in the level of its accumulation by particle-size fractions are noted for dark illuvial-humus burozem. An important diagnostic feature of dark illuvial-humus burozem is that the fine-dusty fraction participates in the accumulation of organic matter more than the silty fraction, both in the upper humus horizon and in the sub-humus horizon. In the lower part of the profile of all burozems, the concentration of humus in the silt increases almost twice, accounting for more than half of its gross content in the soil.