Soil water transport and plant water use patterns in subsidence fracture zone due to coal mining using isotopic labeling

With more underground coal mining, soil subsidence and fracture have increasingly developed and resulted in changed hydrological progress; however, the effects of subsidence fracture on plant water uptake patterns remain largely unknown. This study aimed at investigating whether there were variations in soil water transport and plant water use patterns in subsidence fracture zone and fracture-free zone compared to the non-mining areas. The isotopically labeled water (2H) injection experiments were conducted and the MixSIAR model was used to explore the mechanism of soil water infiltration and water sources of Artemisia Desertorum in a semi-arid coal-mining area. The results showed that: (1) the proportion of the preferential flow in the subsidence fracture zone from the water balance equation was 18.2%; (2) in non-mining zone, 59.7% of water used by Artemisia Desertorum was from the 10–20 cm soil profile layer; (3) in the fracture-free zone, 46.6% and 39.4% of water were from the 40–60 cm and 0–10 cm layers, respectively; and (4) in the subsidence fracture zone, 85.9% of water derived mainly from the 40–60 cm layer. This study provided new insights into soil water transport and plant water uptake patterns in the subsidence fracture zone of coal-mining areas.