Diagnostic parameters of soil formation in gray forest soils of abandoned fields overgrowing with pine forests in the middle reaches of the Angara River

The content, differentiation in the profile, and dynamics of the mobile iron compounds can serve as adequate diagnostic parameters of the direction of the pedogenesis upon the overgrowing of abandoned fields with pine forests in the middle reaches of the Angara River Region in the area affected by the Bratsk water reservoir. The bulk chemical composition of the soil remains relatively stable in the entire profile against the background of the eluvial-illuvial redistribution of the finest particle-size fractions and mobile iron compounds under the impact of the long-term seasonal freezing, the percolative soil water regime, and the alternating redox conditions. The development of accumulative processes in the soil is accompanied by the weak manifestation of eluvial and pulsating gley processes as the initial stages of podzolization under the influence of the growing pine forests.