Features of the Composition of Humus Horizons of Arid Soils in the Barguzin Depression

Resumo

Various types of arid soils that formed under the environmental conditions of the ultracontinental climate at the northern boundary of the steppe distribution in central Asia have been studied. The survey results for the surface horizons of the steppe soils and the soils of the contact forest–steppe zone according to the color characteristics and the humus properties are reported. The dominant cryo-humus accumulation in the soils of the steppe ecosystem and the light-humus soils of the contact zone are determined according to the Munsell scale and the CIE-L*a*b* color system. The ratio of labile and bioinert fractions of the humus compounds may serve as diagnostic parameters. Cluster analysis is performed based on 25 parameters of the soil humus horizons. The first cluster unites the steppe soils with the cryo-humus accumulation, while the second cluster involves soils with light-humus accumulation. Soils with the AK–BCA–Cca profile are classified at the current survey stage as cryo-humus soils. The obtained data can be used to correct the status of cryo-arid soils in the soil classification system.