Abstract: The Sanjiang Swamp and Wetland Ecology Test Station was selected as a research base,where 28 soil samples were taken from 6 typical sampling sites(soils at the beginning and the end of the drainage ditch,swamp soil,and swampy meadow soil)for determination of major ions(HCO₃^- 、Cl^- 、NO₃^- 、SO₄ ^{2 -} 、Ca ²⁺ 、Mg ²⁺ 、K⁺ 、Na⁺),heavy metals(Fe,Mn,Zn,Cu),nutrient elements and their availability,soil organic matter,and soil pH. On such a basis ,effect of drainage on content of chemical elements in the swamp soil was studied. Results show that drainage makes the swamp soil lose a large quantity of chemical elements.

Key words: chemical elements, drainage, Sanjiang Plain, swamp, wetland