Long-term recovery of compacted reclaimed farmland soil in coal mining subsidence area

• Published in: Ecological indicators 2024-11, Vol.168, p.112758, Article 112758
• Main Authors: Liu, Zhaoxinyu, Liu, Shuangjiao, Gao, Lina, Li, Junying, Li, Xinju, Jing, Zhaorui, Song, Wen
• Format: Article
• Language: English
• Subjects: Coal mining subsidence area; Complex network theory; Land reclamation; Reclaimed farmland soils; Soil compaction
• ISSN: 1470-160X
• DOI: 10.1016/j.ecolind.2024.112758

•Compaction during geomorphic reshaping severely damaged RMS ecosystem.•The first 12 years post-recultivation are key for soil structure-led RMS recovery.•POC accumulation promotes soil aggregation in compacted reclaimed soils.•Microbially mediated C-N cycling drives RMS system recovery. During the reclamation process of coal mining subsidence areas, mechanical compaction hinders the rapid recovery of reclaimed mine soil (RMS) functions to their pre-mining levels. To optimize reclaimed farmland management, which can promote the recovery of compacted soils, this study aims to explore the key factors and underlying mechanisms affecting RMS recovery from a systemic perspective using complex network theory (CNT). Soil samples from reclaimed farmland at different recovery stages (0, 2, 6, 12, 16, and 22 years) and adjacent non-subsided cultivated soils (NCS) were collected at a depth of 0 ∼ 20 cm in the eastern plains mining region of China. Twenty-four soil indicators were measured, and their evolution over RMS recovery was analyzed. CNT was employed to systematically analyze the complex network relationships among these indicators, identifying key factors and underlying mechanisms affecting RMS recovery. The results indicated that compaction led to soil macroaggregate (MA) destruction, mineralization losses of organic carbon and nitrogen, reduced microbial activity, degraded soil fertility, and increased complexity and disorder in the relationships among soil indicators. Re-cultivation had a positive effect on the recovery of RMS. After 22 years of cultivation, significant improvements in soil structure were observed, with MA increasing by 30.95 % (P