Abstract:In order to investigate water-salinity distribution characteristics in wetted soil of moistube fertigation, the infiltration experiment of moistube irrigation was carried out under different pressure heads and soil bulk densities, the 0.3% potassium nitrate solution was used in infiltration experiment, and three pressure heads (H1.0:1.0m, H1.5:1.5m and H2.0:2.0m) and three soil bulk densities (D1.00:1.00g/cm3, D1.15:1.15g/cm3 and D1.30:1.30g/cm3) were designed to study the water-salinity distribution and spatial variation traits in wetted soil of moistube irrigation. The results showed that pressure heads and soil bulk densities had significant effect on average contents of moisture, NO-3N and K+ in wetted soil. Under the same soil bulk density, compared with H1.0, the sectional area of wetted soil of H1.5 and H2.0 was increased by 13.50%~21.61%, average contents of moisture, NO-3N and K+ were increased by 3.69%~10.71%, 7.80%~10.95% and 7.29%~17.49%, respectively, and uniformity coefficients were increased by 7.65%~18.63%, 5.22%~13.63% and 9.34%~21.89%, respectively. Under the same pressure head, compared with D1.00, the sectional area of wetted soil of D1.15 and D1.30 was decreased by 5.76%~9.21%, average contents of moisture and NO-3N were decreased by 15.73%~21.54% and 8.08%~10.97%, but average content of K+ was increased by 34.89%~64.79%, and uniformity coefficients of moisture, NO-3N and K+ contents in wetted soil were decreased by 9.02%~11.45%, 4.04%~7.25% and 7.09%~11.54%, respectively. K+ distributed intensively around moistube and accounted for 40.80%~61.41% of distribution area of wetted soil. Average contents of the moisture, NO-3N and K+ in wetted soil of moistube irrigation and the horizontal distance from moistube conformed to the four-parameter Log-logistic model. The research results can provide theoretical basis and practical reference for moistube fertigation.