PLANT COMPOSITION AND SOIL PROPERTIES DURING POSTAGROGENIC EVOLUTION IN THE CIS-BAIKAL FOREST-STEPPE ZONE

Abstract

Purpose. The purpose of the study was to examine the features of the restoration of plant communities and some properties of gray forest soils, including the humus state, during their post-agrogenic transformation in the conditions of the Cis-Baikal forest-steppe zone.
 Materials and methods. The study was carried out using the post-agrogenic chronosequences, including arable land, abandoned soils of different ages, and natural cenoses (meadow and forest). Traditional methods of phytocenology were applied to study the plant composition. Mixed soil samples from three trenches were collected from the former arable layer of 0–20 cm. The content of organic carbon (Corg), total nitrogen (N), and the C/N ratio, the pH(H2O) and pH(KCL) values, as well as soil density and the reserves of Corg were determined. The statistical processing of data was performed using One Way ANOVA (Sigma Plot from Windows Version 14.0).
 Results. It was shown that plant vegetation being typical for the Baikal forest-steppe zone was recovering after the cessation of plowing. At the same time, the several ruderal species were preserved in the plant composition during a long period. This specific phenomenon could be the cause for inhibition of terminal phytocenoses formation. Along with the change in the vegetation, a significant increase in the organic carbon content was revealed in the soils of chronosequences. At the later stages of post-agrogenic succession the carbon reserves in soil were 1.5 times higher than those in arable soil. The humus content in the soils increased with age of the abandoned lands, but no cardinal changes in its qualitative composition were observed. The data indicated the stable functioning of the system of humus substances in the gray forest soils of the Baikal forest-steppe zone during their post-agrogenic evolution.
 Conclusion. The results can be used for the forecast of post-agrogenic soil changes under various scenarios of land use in conditions of the Baikal region.