Self-restoration of post-agrogenic soils of Calcisol-Solonetz complex: Soil development, carbon stock dynamics of carbon pools

Background

Abandoned land may move towards self-restoration without human intervention. In the European part of Russia, over half a million km² was abandoned between 1987 and 2007; another 200,000 km² was abandoned in Eastern Russia. The majority of abandonments occurred in unirrigated dry steppe, land that is arable but less favorable for agriculture. This study compares differences in self-restoration based on underlying soil types, climate, and land-use history across a chronosequence of abandoned land in the dry steppe zone of Russia in a Calcisol–Solonetz complex, reporting on vegetation and soil characteristics.

Research goals & methods

During self-restoration without direct human impact, the vegetation developed towards a steppe with dominance of Artemisia lercheana/pauciflora and Stipa pennata. After 17 years, the abundance of Artemisia pauciflora indicated again the Solonetz locations within the Calcisol–Solonetz complex, which were not apparent during arable land use. Plow features were still well visible after 42 years of self-restoration in both soil groups. Development towards natural soils was observed in terms of soil organic carbon (SOC) dynamics. SOC stocks of the Calcisols increased slowly from 2.0 to 3.5 kg m⁻² in the upper 0.5 m, comprising 64% of the natural soil. SOC stocks of the Solonetzes grew from 1.7 to 3.1 kg m⁻² in the upper 0.5 m and almost reached the level of natural soil after 12 years of self-restoration. Nutrient dynamics correlated with SOC dynamics during self-restoration.

Conclusions & takeaways

The study showed no full restoration for many parameters within the chronosequential time scale of 42 years. Long-term modelling showed a recovery of SOC stocks almost after 100 years for the Calcisol and the Solonetz chronosequences.