The contents of soil organic carbon (SOC)

dissolved organic carbon (DOC)

and microbial biomass carbon (MBC)

as well as profile distribution and its relationships in the four main soil types (Lime concretion black soils (LS)

Fluve-aquic soils (FS)

Paddy soils (PS)

and Red soils (RS)) in Anhui Province are studied. Results showed that the contents of SOC

DOC

and MBC were significantly different in the four soils

but the trend of their profile distributions was basically the same. The contents in topsoil were higher and decreased with soil depth increasing. The orders of SOC

DOC

and MBC in topsoil were PSLSFSRS

LSFSPSRS

and FSLSRSPS

respectively. DOC and MBC were only a small part of SOC. The percentages of DOC and MBC over SOC were in the range from 4.92% to 18.97% and from 1.86% to 5.68%

respectively. There was a close relation among SOC

DOC

and MBC. The relationships between SOC and DOC

between SOC and DOC

and between DOC and MBC were all significant or very significant at 10%

5% or 1% level

respectively.