Structure of the sod-lithogenic soil on red-clay burіh clays: the environmental aspect

Abstract

The dynamics of spatial heterogeneity of the sod-lithogenic soil on red-clay burіh clays has been studied in the environmental aspect in terms of hardness. The ecomorphic analysis of vegetation of the section was carried ont. The ordination of data of soil hardness has been realized by the non-metric multidimensional scaling. The three-dimensional variant of multidimensional scaling was applied. The relationship of varying the hardness of the soil and environmental factors has been determined using phytoindicative scales. Using the technique of spatial data analysis (PCNM) the elements of spatial autocorrelation data of soil hardness and defined processes underlying its formation have been highlighted. It was established that statistically significant phytoindicative scales describe from 7 to 49% of the variability of the multidimensional measurements. Temperature value of soil and cryoregime have a value for the formation of the first coordinate axis. The axis marks the conditions distinguishing soil hardness in layers of 10–35 cm from those located above and below of the selected block. The second coordination axis reflects the opposite phenomenon in soil structure above and below the level of 20 cm and describes the representation of gigromorphes in plant community. The highest values in the formation of the third coordination axis have light scales and ombroregime. Measurement selects the contrast on the basis of hardness at the level 10–35 cm from the surrounding soil layers. During fractionation of variations hardness of the studied soil site it was established that environmental factors determine 56 % of the total variability of the results. PCNM-variables describe 7 % of the variation of indicators of soil hardness and spatial patterns deterministic environment – 10 % of feature variability. Herewith the most important environmental factors for describing of large-scale spatial component of variation of soil hardness are the content of carbonate salts, digestible forms of nitrogen, thermo- and ombroregime, salt regime and continentality climate. The components of the spatial variability of the hardness of a long-period fluctuations are associated with the distribution of plant gigromorphes. Spatial variability of detailed scale components is dependent on soil aeration and ombroregime. High-frequency periodic oscillations of hardness are related to such factors as aeration of the soil, ombroclimate and also distribution structure of trophomorphes, gigromorphes and heliomorphes.

Keywords

• soil hardness
• phytoindicate
• multidimensional scaling