Quantitative estimation of groundwater recharge in the thick loess deposits using multiple environmental tracers and methods

•Understanding groundwater recharge is important in arid region with thick vadose zone.•Piston flow recharges groundwater accounting for 200 years. The recharge rates range from 0 to 37 mm year−1, equivalent to 0–7% of annual average precipitation. However, the deep-rooted vegetation greatly reduced deep drainage compared with shallow-rooted vegetation, which will perturb the current hydraulic connectivity between unsaturated and saturated zones. The multiple tracers and methods can complement each other to enhance the understanding of groundwater recharge mechanisms. The indicated relationship between recharge form and land use suggests the urgency in developing strategies to balance the agroforestry system and water resource sustainability.