Post-reclamation land use effects on properties and carbon sequestration in minesoils of southeastern Ohio

摘要

Reclamation of mined soils could restore soil quality and ecosystem productivity and sequester C, but limited data exist with regard to the impact of post-reclamation land use and management on soil organic carbon (SOC) storage in reclaimed minesoils (RMS). A study was conducted to evaluate SOC and total nitrogen (TN) stocks (0-50 cm depth) and related soil physical and chemical properties for reclaimed grassland sites maintained under four distinct management practices for 24 years, namely, meadow, hay, grazing, and grazing-feeding. A nearby undisturbed grassland was used as a baseline or reference. Bulk density of the RMS (range: 1.16-1.88 mg m-3) was significantly lower for the hay and meadow than the grazed sites (P < 0.05). In addition, RMS under hay and meadow practices had greater concentration of water-stable aggregates (WSA) and larger mean weight diameter (MWD) of aggregates than the grazed sites. Soil pH and electrical conductivity (EC) were higher in the RMS than the undisturbed soils. Among the reclaimed sites, pH and EC values were generally lower (P < 0.05) in meadow than grazing and grazing-feeding practices. The SOC was generally higher in the grazing-feeding and hay sites (89 and 76 mg ha-1, respectively) than meadow (64 mg ha-1), grazing (70 mg ha-1), and undisturbed grassland (72 mg ha-1). The data suggest that removal of aboveground biomass for hay had no impact on SOC accumulation in these grasslands. Nearly 50% of the root biomass accumulated in the top 0-10 cm in the reclaimed grassland sites. The SOC content was strongly correlated with MWD (R2 = 0.70, P < 0.01), and root biomass (R2 = 0.75 P < 0.01) indicating that both roots and aggregates play a significant role in SOC accumulation in RMS.