| To explore the effects of typical exogenous salt (NaCl) concentration on the yield of Lycium barbarum and soil environmental factors under brackish water irrigation, and to identify the optimal salt concentration for irrigation in different brackish water quality areas, a field experiment was conducted downstream of the Hetao Irrigation District from April to October 2022. Four NaCl concentration treatments (0.1, 0.5, 2.0, 4.0 g·L-1) along with a control (CK, clean water) treatment were established to analyze changes in soil water salinity, pH, and sodium adsorption ratio (SAR) in the soil layers from 0 to 100 cm, as well as the growth characteristics of Lycium barbarum. The results showed that under brackish water irrigation, the soil water moisture content was increased by adding different exogenous NaCl concentrations, and the soil moisture water content was significantly higher in the treatment with a concentration of 4.0 g·L-1 irrigation water salt concentration than the other treatments. Soil electrical conductivity increased linearly with the increase of the irrigation salt concentration, under 0.1 g·L-1 treatment, the salt content of 30~40 cm soil layer was the least. During the growth period of Lycium barbarum, soil pH increased with the increase of salt concentration of irrigation water, and there was no significant difference between CK and low NaCl concentration treatment (<0.5 g·L-1). At 4.0 g·L-1, soil pH was the highest, which increased by 3.27% compared with CK. In 0~40 cm soil layer, the SAR of 0.1 g·L-1 treatment was the smallest, which decreased by 9.90%，7.53% and 20.38% compared with 0.5，2.0 and 4.0 g·L-1, respectively. When NaCl concentration was greater than 0.5 g·L-1, the growth rate of new branches, ground diameter and crown width was inhibited. When NaCl concentration was 0.1 g·L-1, the yield of Lycium barbarum decreased by 26.49% compared with CK treatment. In conclusion, adding brackish water with a NaCl concentration of less than 0.5 g·L-1 to Cl-Na water quality can help conserve freshwater resources and prevent secondary soil salinization in the Hetao irrigation area. The research findings provide valuable technical support and a theoretical foundation for the safe use of brackish water in areas with similar water quality conditions in the Hetao irrigation area. |