Adaptive water use strategies of Mongolian pine plantations in response to mining subsidence across two soil types: a case study in Northwest China

Abstract Understanding plant water use strategies is critical for managing and restoring ecosystems affected by coal mining subsidence. However, how subsidence impacts water use strategies, especially across different soil types, remains inadequately explored. To address this gap, we employed a continuous isotopic mixing model (based on δ2H and δ18O), coupled with δ13C, soil water content and root distribution, to investigate the differences in water use strategies of Mongolian pine plantations in coal mining subsidence and non-subsidence areas with sandy and loess soils. Our results show that subsidence induces preferential flow, increases deep soil water (80 cm), and enhances root growth and soil water-root coupling, especially in the loess areas. Isotopic mixing modeling revealed that in sandy areas, deep soil water uptake was similar between non-subsidence (79.43 ± 3.83%) and subsidence (82.69 ± 1.52%) plots. In loess areas, subsidence plots (26.36 ± 1.98%) had significantly higher deep water uptake than non-subsidence plots (16.23 ± 1.91%, P .01). Leaf δ13C values decreased significantly in both soil types under subsidence, indicating reduced water stress via deep water utilization, particularly in loess areas. Soil-type dependent response highlights the necessity for distinct vegetation maintenance or restoration strategies in subsided areas across different soil matrices. These findings advance understanding of plant survival strategies and water resource relationships in subsidence zones, providing valuable references for sustainable land and water management in mining-impacted areas.