Abstract: An in situ field investigation was conducted to study the distribution characteristics and related affecting factors of microbial biomass carbon (MBC) and dissolved organic carbon (DOC) in two types of  Deyeuxia angustifolia marsh soils in Sanjiang Plain. In D. angustifolia  wet meadow and  D. angustifolia  marsh meadow, the soil MBC and DOC contents in May-September were averagely 769.2 and 312.3 mg·kg^-1, and 2447.3 and 404.4 mg·kg ^-1 , and the proportions of soil MBC and DOC to soil total organic carbon were 2.50% and 1.03%, and 3.53% and 0.59%, respectively. Both the soil MBC and the soil DOC had the characteristics of obvious seasonal change, and their contents decreased with soil depth. Organic matter input, humus content, and water condition were the main factors affecting the distribution of soil MBC and DOC in  D. angustifolia  marsh soils.

Key words: Acid sulfate soil, Sulfur forms, Transformation