Abstract:The main forest areas of Shaanxi Province lie in the Qinling Mountains. These forests have important ecological and economic significance. The distribution patterns of soil organic carbon (SOC), total nitrogen (TN), and SOC storage in the soil profiles have not been systematically studied. The objective of this study was to estimate SOC, TN, and SOC storage for six forest types in the Matoutan forest farm and in the Xinjiashan forest farm of the Qinling mountain range. All forest types in this study were natural secondary forests: namely Quercus aliena var acuteserrata (Matoutan forest farm), Pinus tabulaeformis Carr, Pinus armandii Franch, pine-oak mixed forest, Picea asperata Mast, and Quercus aliena var acuteserrata (Xinjiashan forest farm). Five replicate samples were taken in an "S" pattern for each forest type. The profiles were divided into 0-10, 10-20, 20-40, and 40-60 cm groups and then sampled, summing up to 72 soil samples. The physical and chemical properties of the soils were measured using conventional methods. The results were analyzed using univariate analysis of variance. Differences among forest types and soil horizons were analyzed with SPSS statistics 18.0. The results showed that the content of SOC and TN of different soil layers decreased with increasing soil depth in all six soil profiles. The accumulation and decomposition of SOC and TN differed between forest types. Among the six forest types, the SOC and TN contents of Picea asperata Mast and pine-oak mixed forest were higher than in the others, and that of Quercus aliena var. acuteserrata (Xinjiashan forest farm) was the lowest. The SOC and TN content in the intervals of the six forest soils were 13.46-26.41 g/kg and 4.47-9.51 g/kg, respectively, and the order was Picea asperata Mast > pine-oak mixed forest > Quercus aliena var acuteserrata (Matoutan forest farm) > Pinus tabulaeformis Carr > Pinus armandii Franch > Quercus aliena var. acuteserrata (Xinjiashan forest farm). The ratio of carbon to nitrogen (C/N) ranged from 5.93 to 15.47, the mean C/N was in the order of pine-oak mixed forest > Pinus armandii Franch > Pinus tabulaeformis Carr > Picea asperata Mast > Quercus aliena var acuteserrata (XinJiashan forest farm) > Quercus aliena var acuteserrata (MaToutan forest farm). SOC storage of the 0-60 cm layer of the six soils was 150.94 t/hm2 for Picea asperata Mast > 135.28 t/hm2 for Quercus aliena var acuteserrata (Matoutan forest farm) > 124.93 t/hm2 for Pine-oak mixed forest > 109.24 t/hm2 for Pinus armandii Franch > 102.15 t/hm2 for Quercus aliena var acuteserrata (Xinjiashan forest farm) > 96.62 t/hm2 for Pinus tabulaeformis Carr, which was greater than the national average SOC storage (96.0 t/hm2). SOC storage was influenced by SOC content, soil bulk density (BD), soil thickness, and volume of gravel; therefore, the distribution regularity in the soil profile was poorer. Correlation analysis showed that there were highly significant positive correlations between SOC and TN, but no significant correlations between C/N and SOC and TN.