Abstract: Characteristics of distribution and composition of sulfur in soils of typical meadow Calamagrostis angustifolia wetland and marsh meadow Calamagrostis angustifolia wetland in the Sanjiang Plain were studied.Results show that total sulfur in both wetlands are in the range from 303.39 to 520.83 mg·kg^-1 and from 303.74 to 1 219.81 mg·kg^-1,respectively,averaging 391.62 and 513.03 mg·kg^-1 respectively,both lower than the average of the world soil.Sulfur accumulates mainly in the upper layer of the soils in the form of organic sulfur,which constitutes about 90% of total sulfur.Carbon-bonded sulfur forms the largest portion of organic sulfur,accounting for 45.34% and 37.24%,respectively in the wetlands.The marsh meadow Calamagrostis angustifolia wetland is higher than the typical meadow Calamagrostis angustifolia wetland in both the content and variability of soil sulfur of various forms.In the two kinds of wetlands,all forms of sulfur displayed obvious characteristics of vertical distribution and variability.Content of organic matter in the soil is the important factor affecting the content of sulfur,which is also affected by contents of soils of various particle size fractions.Moreover,the contents of soil sulfur of various forms are also correlated with each other.

Key words: Sanjiang Plain, Calamagrostis angustifolia wetlands, soil, sulfur, composition, vertical distribution