Hillslope scale temporal stability of soil water storage in diverse soil layers

•Analysed soil water storage (SWS) temporal stability in three layers on two hillslopes.•Spatial variation in mean SWS increased with increasing soil depth.•At greater depths, soil water storage tended to be more temporally stable.•A representative site can estimate mean soil water storage on a hillslope.•Strong temporal stability due to texture, organic carbon, elevation, vegetation. Knowledge of the soil water storage (SWS) of soil profiles on the scale of a hillslope is important for the optimal management of soil water and revegetation on sloping land in semi-arid areas. This study aimed to investigate the temporal stability of SWS profiles (0–1.0, 1.0–2.0, and 2.0–3.0m) and to identify representative sites for reliably estimating the mean SWS on two adjacent hillslopes of the Loess Plateau in China. We used two indices: the standard deviation of relative difference (SDRD) and the mean absolute bias error (MABE). We also endeavored to identify any correlations between temporal stability and soil, topography, or properties of the vegetation. The SWS of the soil layers was measured using neutron probes on 15 occasions at 59 locations arranged on two hillslopes (31 and 28 locations for hillslope A (HA) and hillslope B (HB), respectively) from 2009 to 2011. The time-averaged mean SWS for the three layers differed significantly (P