Capacity of soil water storage and regulation under different density forests of Tamarix chinensis Lour in coastal wetland

The objective is to explore the suitable forest density of Tamarix chinensis Lour on the capacity of soil water storage and regulation of wetlands in Yellow River Delta. The characteristics of soil water physical properties, soil infiltration, soil water storage and regulation of Tamarix chinensis under different density forests are analyzed. Soil infiltration course and hydrological properties are determined in field and laboratory. The results show that: ① The amount of fine sand increased with the density forests of Tamarix chinensis increasing, while the amount of silt and clay decreased. The effect of controlling soil salinity and alkaline content of middle density forest is better than that of high and low density forests, and the soil salinity and alkaline content of 0-20 cm is lower than that of 20-40 cm; ② Soil density decreased and then increased with the density forests of Tamarix chinensis increasing, while the soil porosity show a contrary tendency. Compared to the total porosity of low density forest, the increment of that in the middle, high density forest and grassland is 12.9%, 6.2% and 4.4%, respectively, and these indexes of 0-20 cm are better than that of 20-40 cm; ③ Soil infiltration course of forest field fitted Horton infiltration model well. Characteristics of soil infiltration show this order: Middle density forest>high density forest>low density forest> grassland; ④ Characteristics of soil saturated water content, soil capillary, non-capillary porosity water-holding capacity and total absorption precipitation show this order: Middle density forest>high density forest>grassland>low density forest, and the capacity of soil water storage and regulation in 0-20 cm is better than that of 20-40 cm. Compared to the capacity of total absorption precipitation in low density forest, the increment of that in the middle, high density and grassland is 28.4%, 23.8% and 14.1%, respectively. The largest capacity of soil water storage and regulation is the middle density forest, followed by high density forest, and low density forest is poor.