Abstract:Soils in wetlands under returning farmland to lake with different vegetation types(Carex maximowzczii>Rumex acetosa Linn.and Phragmites australis)were sampled to analyze the effects of the three vegetation types on soil organic matter,total P and available P and their distributions in soil profiles in the Caizi Lake.Results showed that soil organic matter content in 0-6 cm layer were the highest under Rumex acetosa Linn. and the lowest under Phragmites australis.Moreover,soil organic matter contents in 6-13 cm,13-25cm,25-40 cm,and 40-55 cm layers were in the order of Phragmites australis and Carex maximowicziiand Rumex acetosa Linn.and decreased with soil depth under all the three vegetation types.The contents of total P under all the three vegetation types were high in 0-6 cm layers and the lowest in 6-13 cm layers,and then increased with soil depth.Available P contents decreased with soil depth in all the soil profiles,and there was no significant difference in the same soil layers under different vegetation types except that Rumex acetosa Linn.was higher than Phragmites australis and Carex maximowiczii in 0-6 cm layer. There was no significant difference of soil phosphorus efficiency in all the same soil layers under different vegetation types except that Rumex acetosa Linn. was higher than Phragmites australis and Carex maximowiczii in 0-6 cm and 6-13 cm layers.Litters and root distribution under different vegetation types were the cause of distribution variation of organic matter and phosphorus in soil profiles,and farmyard manure for the aquacul-ture also caused soil nutrient accumulation in surface soils.