Based on the sampling (0-10

10-20

20-30 and 30-40 cm) and lab analysis of two representative natural secondary oak forest plots in Liaodong mountain area

which was located in the town of Benxi City River Estuary and the fairy town of Zhuanghe City

the distribution characteristics of soil organic carbon

total nitrogen

and total phosphorus at the depth of 0-40 cm was studied

and the relationship between organic carbon and other physical and chemical properties was discussed. Results showed that soil organic carbon

total nitrogen

total phosphorus

total potassium

available nitrogen

available phosphorus

available potassium and cation exchange capacity tended to decline with the increasing soil depth

however soil bulk density generally increased with increasing soil depth. According to the t test and variance analysis

there was a significant difference between the experiment indicators and the soil layer (P<0.05). Moreover

the content of silt showed a very high positive correlation with the soil organic carbon

pH value

total nitrogen

total phosphorus

total potassium

alkaline hydrolysis nitrogen

available phosphorus

available potassium and cation exchange capacity (r=0.430 9~0.919 0

n=44

P<0.01). While soil bulk density and the content of sand had a significant negative correlation with soil organic carbon (r=0.388 3~0.670 6

n=44

P<0.01). But the content of clay had no significant correlation with soil organic carbon. Stepwise regression analysis showed that the relationship between soil available nitrogen

the ratios of carbon to nitrogen

total potassium

pH

total nitrogen and organic carbon was the closest. Overall

there was close relationships between soil organic carbon and other physical and chemical properties

and the total nitrogen

available nitrogen

the ratios of carbon to nitrogen

total potassium and pH had big impact on it. At the same time

each index had obvious profiles distribution.