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

摘要

Soil humus substances are considered as a multicomponent system of amphiphilic (exhibi t ing both hydrophilic and hydrophobic properties) substances. Hydrophilic components of humus su b stances ensure the eluvial and eluvial — illuvial differentiation of the soil profile; hydrophobic comp o nents are responsible for the accu mulative type of humus profile and the water stability of soil aggr e gates. Possible mechanisms for the formation of hydrophobic - hydrophilic properties of humus su b stances and its role in stable aggregates formation are discussed. The suitability of mathema tical equations has been considered for the description of the decomposition dynamics of the soil aggr e gates in time, the selection of the best model, and the statistical analysis of the parameters of the corresponding models. The quantitative analysis of the interrel a tions between the parameters characterizing the water stability and the characteristics of the soil organic matter has revealed a unimodal relationship b e tween 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 aggregat es water stability of typucal chernozem is about 60% of hydrophilic and 40% of hydrophobic components in the compos i tion of soil organic matter .