Abstract: The study on the profile (0-100 cm) distribution and seasonal variation of soil dissolved organic carbon (DOC) in a natural Castanopsis fabric forest in Jian’ou of Fujian Province showed that the mean concentration of DOC had a decreasing trend with the increase of soil depth. In 0-5 cm soil layer, the mean concentration of DOC was 55.69 mg·kg^-1, being significantly higher than that in other soil layers (P<0.01). The ratio of DOC to soil organic carbon (SOC) also decreased with increasing soil depth, and its mean value in the profile was about 0.14%. In all seasons, the concentration of DOC in the profile had a decreasing trend with the increase of soil depth, which was most obvious in winter. The seasonal variation of DOC concentration in the profile was in the order of inter>autumn>spring>summer. There was a less variation of DOC/SOC ratio in different soil layers among different seasons. Different soil layers had significant differences in the seasonal variation of DOC, which was most significant in 0-5 cm soil layer (P<0.01).

Key words: Alatai region, Grassland type, Ecological service value, Grassland function, Classified management