Influence of Long-term Irrigation with Reclaimed Water on the Soil Quality of Different Land Use Types

With increasing population size and rapid economic development, water resource shortages are becoming increasingly prominent and directly affect the sustainable development of society. As an unconventional water resource, reclaimed water has several advantages, such as being unaffected by climate, being stable and reliable, and being widely used for vegetation irrigation. Nevertheless, long-term safety of irrigation with reclaimed water (IRW) is difficult to ascertain. This study aimed to investigate the influence of long-term IRW on soil quality. The soils of three land use types (grassland, shrubland, and woodland) under IRW for 6 years and no irrigation with reclaimed water (NRW) were used as the research objects. Soil of the NRW treatment served as the control. The results demonstrated that IRW negatively affected soil aggregate development and stability. This resulted in decreases in soil void ratio (VR) and saturated hydraulic conductivity (Ks), and a rise in bulk density (BD). In addition, IRW had the strongest negative impacts on the soil moisture availability of shrubland areas, which was not conducive to plants fully utilizing soil moisture. Fortunately, IRW elevated soil nutrient content but did not lead to soil salinization or alkalization. The soil quality assessment revealed that long-term IRW had no significant impact on soil quality. The reclaimed water could be considered suitable for irrigating plants, and priority could be given to woodland and grassland areas. These results provide a reference for optimizing reclaimed water irrigation strategies, and alleviating the pressure of water resource scarcity.