Soil aggregation and aggregate‐associated organic carbon flows are affected by different restoration patterns on reclaimed mine soil in the Loess Plateau of China

Abstract Vegetation restoration of land post‐mining can strengthen the development of soil aggregates and promote the accumulation of soil organic carbon (SOC), and Microbial restoration such as Arbuscular mycorrhizal fungi (AMF) can significantly improve the effect of vegetation restoration. However, the effects of different recovery modes (microbial and natural restoration) on soil macroaggregates development and the carbon flows of the organic carbon (OC) have been less studied on reclaimed mine soil. A 4‐year field experiment was conducted on opencast coal reclaimed areas in Inner Mongolia grassland, and three recovery modes were set up: artificial restoration, artificial restoration (inoculated with AMF) and natural restoration. Results showed that compared with the natural restoration, artificial restoration and AMF inoculation increased the OC, total glomalin‐related soil proteins (TGRSP) contents and the value of δ13C in macroaggregates (>0.25 mm) in deep soil (30–50 cm). The shallow roots were the most likely starting points of carbon flow in the natural recovery area surface soil, and artificial restoration inoculation with AMF increased the carbon flows between all levels of aggregates in deep soil, showing a carbon flow pattern from macroaggregates to microaggregates (<0.25 mm). Moreover, significant correlations among the TGRSP, SOC content, and δ13C value were recorded, indicating the SOC sequestration and stability of reclaimed mine soil were potentially associated with TGRSP. In summary, both natural restoration and artificial restoration had advantages and disadvantages on reclaimed mine soil, but the artificial restoration inoculation with AMF showed great potential in promoting the aggregate carbon flow and persistent SOC accumulation.