Background and aims <p><i>Platycladus orientalis</i> is vital for restoration in the western Loess Plateau, aiding soil and water conservation and carbon sequestration. Understanding its water use strategies and responses to water inputs is crucial for sustainable water management and vegetation restoration. However, its strategies under different water management methods (rain-fed, flood, sprinkler irrigation) and optimal resource allocation under irrigation remain unclear.</p> Methods <p>The water use strategies of <i>P. orientalis</i> were investigated under three water management conditions: rain-fed, flood irrigation, and sprinkler irrigation. The hydrogen and oxygen stable isotope technique was used to determine water use strategies.</p> Results <p>The primary water source for <i>P. orientalis</i> differed depending on the water management method. Under rain-fed and sprinkler irrigation (both dry and rainy seasons), shallow soil water (0–40&#xa0;cm) was the main source (contributing 59.2% and 61.3%, respectively). Under flood irrigation, the <i>P. orientalis</i> relied predominantly on shallow soil water (36.3%) and the irrigation water (17.1%). <i>P. orientalis</i> exhibits a preference for readily available water sources. The species can promptly adjust its water source uptake following rainfall or irrigation events. It displayed heightened sensitivity to water input events. These behaviors demonstrate considerable plasticity in water absorption and strong adaptability to ecological environments.</p> Conclusion <p>The findings reveal significant plasticity in the water use strategies of <i>P. orientalis</i>, allowing it to adapt to different water management regimes and ecological conditions. This research provides valuable insights for optimizing vegetation restoration efforts and water resource management practices in the Loess Plateau.</p>