[Objective] The effects of planting spring wheat and forage grass on salinization of cultivated land were analyzed in order to provide scientific basis for the prevention and control of soil secondary salinization in irrigated region of Northwest China.[Methods] Triticum aestivum

mixed grass (Elymus dahuricus/Medicago sativa) and soil under them were taken as the study objects. The coverage

height

above-ground biomass of vegetation and soil moisture and electrical conductivity were measured to investigate the impacts of spring wheat and forage grass on land salinization.[Results] During the whole growth stage

the coverage

height and biomass of T. aestivum and grass increased significantly. After wheat harvest

wheat field was bare as naked land

while grass still covered the land surface. Compared with the bare land

surface sunlight intensity

temperature and salt content of surface soil (0-5 cm) under vegetation coverage were much lower

while ground humidity and soil moisture content were much higher. Correlation analysis indicated that the strongest correlation occurred between biomass and soil moisture and between coverage and soil salt

and there was a negative relation between soil moisture and salt. Regression analysis demonstrated that soil moisture content increased by 6% as biomass increased by 1 kg/m2

and soil electrical conductivity decreased by 2.2 μS/cm as vegetation cover increased by 1%.[Conclusion] Planting spring wheat in irrigated regions of Northwest China will cause soil secondary salinization

while planting forage grass may weaken hazard of soil secondary salinization.