Abstract:The purpose of this study was to explore the effects of different saline water quality on soil salt properties and crop growth, and to provide scientific basis for saline water irrigation management. A pot experiment was carried out for cropping lettuce in the solar greenhouse. Taking the saturated solution of CaSO4 as a control (CK), different chlorides were added to deionized water to form three saline water treatments with different cationic compositions (Na+, TNa; Na+/K+ of 1:1, TNa-K; K+, TK) on the premise of the same total mole concentration added. The soil salt contents, cations contents, and photosynthetic characteristics, ions uptake and growth of lettuce were studied. The results showed that:(1) At the end of lettuce growing season (80 days after sowing, DAS), the electrical conductivity of saturated extract (ECe) of soil at 0-20 cm depth was significantly higher than those before sowing and 50 DAS, where CK was significantly lower than others (P<0.05). The differences of soil pH values were not significant among different treatments and depths (P>0.05). At the end of the growth season, the soil salt cations mostly accumulated on the surface layer and were consistent with the salt distribution. (2) Compared with CK, single salt ion stresses (TNa and TK treatments) significantly reduced the photosynthetic properties, including net photosynthetic rate, transpiration rate, and stomatal conductance of lettuce (P<0.05), thus resulting in the reduced yield, where the TNa gave the lowest yield per pot. The photosynthetic properties of TNa-K were significantly lower than that of CK, but higher than those of TNa and TK, indicating that TNa-K treatment alleviated the harm of single salt ions to the growth of lettuce. And TNa-K increased yield compared with TNa and TK treatment, but without significantly difference (P>0.05). (3) Compared with CK, TNa and TK significantly increased the Na+ and K+ contents in the lettuce leaves, respectively; while the Cl- content of TNa-K treatment were higher than CK, but significantly lower than TNa and TK (P<0.05). The salt composition with Na+/K+ of 1:1 in saline water could maintain the ion balance of lettuce plants and alleviate the salt stress of single salt ion on lettuce growth, while as for the single ion stress, Na+ should cause the more stress than K+.