Sorption of humus and its distribution in the profile of chernozems depending on the granulometric composition

Abstract

Particle-size composition is a fundamental characteristic that has a significant impact on many properties and regimes of soils, including sorption and fixation of humus by elementary soil particles (ESP). The main role in increasing the humus content of soils belongs to ESP with sizes <0.01 mm. We examined the structural features of humus profiles of leached chernozems formed on soil-forming rocks of different granulometric compositions. For this purpose, a large sample of data on the quantitative content of humus in chernozems of different granulometric compositions was analysed. The goal of the research was to identify the dependence of humus sorption on the granulometric composition of chernozems, and also to reveal the features of the profile distribution of humus in them. Objectives: conduct field research of chernozems of different granulometric composition; select soil samples and conduct a series of laboratory studies of these samples for the identification of the sorption properties of ESP in relation to humus; identify the features of humus distribution in soils of different granulometric compositions. It has been shown that with an increase in the granulometric composition of the content of ESP related to physical clay (<0.01 mm), the sorption capacity of the soil for humus increased. Thus, from sandy loam (ESP <0.01 mm=14-20%) to clayey varieties (ESP <0.01 mm = 61-64%) of chernozems, the humus content increased, respectively, from 3.88 to 7.09%. The thickness of the humus layer increased in the same direction from 22 to 100 cm. Therefore, soils of different granulometric compositions have their own structural features of the organoprofile, consisting in the nature of the humus distribution.