Dependence of aggregates water stability from the contents of hydrophilic and hydrophobic components in the organic matter of chernozems

Abstract

Soil humus substances are considered as a multicomponent system of amphiphilic (exhibiting both hydrophilic and hydrophobic properties) substances. Hydrophilic components of humus substances ensure the eluvial and eluvial—illuvial differentiation of the soil profile; hydrophobic components are responsible for the accumulative type of humus profile and the water stability of soil aggregates. Possible mechanisms for the formation of hydrophobic-hydrophilic properties of humus substances and its role in stable aggregates formation are discussed. The suitability of mathematical equations has been considered for the description of the decomposition dynamics of the soil aggregates in time, the selection of the best model, and the statistical analysis of the parameters of the corresponding models. The quantitative analysis of the interrelations between the parameters characterizing the water stability and the characteristics of the soil organic matter has revealed a unimodal relationship between the parameter responsible for the water stability of the aggregates and the content of the hydrophobic and hydrophilic components for the studied typical chenozem (Voronic Chernozems Pachic, WRB, 2006 or Haplic Chernozems, FAO, 1988)  (Orenburg oblast). The optimal relation between hydrophobic and hydrophilic components for high aggregates water stability of typucal chernozem is about 60% of hydrophilic and 40% of hydrophobic components in the composition of soil organic matter.

Keywords

• soil organic matter, amphyphilic properties, soil structure, water stable aggregates, chernozem, mathematical models, quantitative estimation, comparative analysis, soil properties

References

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