Background Water availability is a major limiting factor for vegetation restoration and reconstruction in semi-arid regions. Studies have shown that differences in plant biological characteristics and spatial structures lead to variations in the improvement effects on soil hydro-physical properties and water conservation functions. Investigating the soil hydro-physical properties, water-holding capacity, and water storage characteristics of different economical shrub in the semiarid western Heilongjiang province can provide theoretical insights into the eco-hydrological properties of regional shrubland soils. This research will aid in selecting economic shrub species conducive to water conservation in semiarid areas.

Methods This study focused on six economically valuable shrub species, Corylus heterophylla, Lycium chinense, Hippophae rhamnoides, Prunus tomentosa, Eleutherococcus senticosus, and Rosa davurica, along with grassland (control). Field sampling and laboratory analysis were combined to measure the soil hydro-physical properties within the 0–60 cm soil layers of these shrubs. Key water storage indices, including water-holding capacity and water storage capacity, were calculated. Comparative analyses were conducted to evaluate differences in soil water storage capacity across different soil layers and shrub species.

Results Except for soil bulk density and retained water storage capacity, other soil water storage capacity indicators were significantly influenced by shrub species and soil layer depth (P < 0.05). Significant differences existed in soil moisture content, bulk density, and porosity among different shrub lands (P < 0.05). P. tomentosa shrubland demonstrated superior performance with its large canopy and deep, extensive root system, significantly increasing soil moisture content (17.33 %), total porosity (51.03%), and capillary porosity (39.70%), while reducing soil bulk density (1.07 g/cm³). In contrast, grassland presented the highest bulk density (1.25 g/cm³) and significantly lower porosity compared to shrub lands, indicating shrubs' superior soil structure improvement capacity through root activities. The six shrublands showed higher soil saturated water-holding capacity, capillary water-holding capacity, field water-holding capacity, saturated water storage, and absorbed water storage than grassland. Notably, P. tomentosa shrubland significantly outperformed other shrubs in both water-holding capacity and water storage (P < 0.05), with other shrubs showing comparable water storage capacities. These advantages stem from canopy precipitation interception, litter-derived humus enhancing porosity, and root-induced compression of soil capillary pores improving capillary forces.

Conclusions Shrubland has a lower soil bulk density, higher porosity, and greater water holding and storage capacity, indicating a significantly stronger soil water storage capacity than grassland. There are considerable differences in soil water storage capacity among different shrublands, with P. tomentosa stands showing notably better soil moisture physical properties, water-holding capacity, and storage performance than other shrubs. Shrubs can enhance soil water storage capacity by improving pore structure and water-holding and storage capacities. In ecological restoration projects in semi-arid regions, priority should be given to deep-rooted, dense-canopy shrubs like P. tomentosa to improve soil water conservation functions.