Sanjing Plain is situated in the northeast part of China.It is one of the areas where marshy soil is widely spread.The area qf marshy soil is over 13,700 km²,about one fourth of the total plain area.Most of the marshy area of Sangjiang Plain belong to the marshy soil without peat accumulation.There is a rom humus horizon(10-20cm thick)between the grass-root and the gley horizon. The marshy soil of Sanjiang Plain may be divided into two great groups, six sub-groups and ten kinds. The textures of most of the marshy soil belong to loam clay—clay.The volume weight of surface stratum is 0.1—0.8 g/cm³.The content of organic matter varies with different sub-groups of marshy soil.The exchangeable cation is about 30—70 m.e/100g,the exchangeable base is 20-40 m.e/100g.The nitrogen content of the marshy soil is sufficient,but contents of phosphorus and potassium are not sufficient;the pH value is 5—7. The marshy soil is a kind of valuable soil resources by which after reclamation,we can develop agriculture,animal husbandry,reed breeding and fertilizermaking,etc.