Abstract: Taking the natural vegetations on the salinized fields having been abandoned for different years in the lower reaches of Shiyang River as test objects, this paper studied the dynamic changes and interrelationships of vegetation succession and soil nutrients. Overall, the vegetation type experienced three stages, i.e., field weeds → desert herbages → desert brushes, while the community succession had four stages, i.e., Convolvulus arvensis + Chenopodium album (1-2 years) → Peganum nigellastrum (3-10 years) → Lycium ruthenicum + Kalidium cuspidatum var. sinicum (10-40 years) → Kalidium cuspidatum var. sinicum (climax community). During community succession, the changes of soil nutrients experienced three stages, i.e., consuming → accumulating → consuming, only soil available K not consumed at the early stage. All soil nutrients were consumed at the late stage, and finally, their contents were approached to the levels under natural vegetations in the area. Because of the consuming of the soil nutrients at the early stage, P. nigellastrum had less contribution to the soil nutrients, being significantly negatively correlated with soil available P but positively correlated with soil available K. L. ruthenicum had positive correlations with soil nutrients, especially with soil organic matter, total N, and the available K in 30-60 cm layer. There were significant negative correlations between K. cuspidatum var. sinicum and soil nutrients, suggesting that K.cuspidatum var. sinicum had strong adaptation to the site conditions, being able to be the proper introducing species to accelerate and direct the vegetation succession on abandoned salinized fields.

Key words: Permanently flooded rice field, Methane emission, Factor analysis, Ridged cultivation