Impact of rainfall on root water uptake in two characteristic species of coal mining subsidence areas in Northwest China

Clarifying how plants utilize water in coal mining subsidence zones is essential for grasping plant-soil dynamics and guiding ecological rehabilitation. However, current knowledge on species-specific variations in water uptake and their adaptive responses to such subsidence remains limited. This research leveraged isotopic fingerprinting (δ2H, δ18O) alongside soil water content and root distribution to explore the root water uptake sources of two predominant species (Stipa bungeana Trin. and Artemisia desertorum Spreng.) in coal mining zones and their reactions to land subsidence triggered by coal extraction. The results indicated negligible differences in soil water content and soil water isotopic composition between subsidence and non-subsidence zones, irrespective of rainfall. Before rainfall, the water sources of the two species were unaffected by subsidence; however, after rainfall, discernible changes occurred. Plants in the subsidence area absorbed more water from the top 0–10 cm soil layer, indicating a more pronounced response to rainwater infiltration. Notably, A. desertorum, in contrast to S. bungeana, tapped into deeper soil water during arid conditions and swiftly switched to shallow soil water sources following rainfall, highlighting its adaptable water usage strategy and greater ecological resilience. The findings of this study cast new light on plant-water relationships in coal mining subsidence regions, providing essential guidance for ecological restoration and management efforts.