Distribution characteristics and influencing factors of soil carbon and nitrogen under different vegetation types in Zibaishan National Nature Reserve

Abstract

Objective The objective of this study is to explore the distribution characteristics of soil carbon and nitrogen under different vegetation types in Zibaishan National Nature Reserve, and analyze its main influencing factors. Method Soil samples were collected from different soil layers, including loam types (Q. aliena forest and P. armandii forest) and sandy types (Q. aliena var. acuteserrata forest, Q. variabilis forest, B. platyphylla forest). The content, density and storage of soil organic carbon (SOC), total nitrogen (TN), and carbon-nitrogen ratio (C∶N) under 5 different vegetation types were compared, and the relationship between SOC, TN, C∶N and soil physical and chemical properties was analyzed. Result (1)The content, density and storage of SOC and TN in the loam soil were significantly higher than those in the sandy soil (P＜0.05). As for loam soil, Q. aliena forest had the largest content, density and storage of SOC and TN, followed by P. armandii forest. For sandy soil, the order from large to small was B. platyphylla forest, Q. aliena var. acuteserrata forest, and Q. variabilis forest. (2)With the increase of soil depth, the content, density and storage of SOC and TN in 0−30 cm soil layer decreased significantly (P＜0.05). (3)Soil C∶N in different soil layers of different vegetation types showed little regularity or differences. The value of C∶N was 9.94−16.23, indicating strong mineralization ability of organic matter. (4)Soil water content (SWC) and bulk density (BD) were the main factors affecting soil SOC and TN content, while SWC and pH were the main factors affecting C∶N. Conclusion There are significant differences in content, density and storage of SOC and TN under different vegetation types, and SWC is a key factor affecting SOC, TN and C∶N. This study has a certain reference value for the protection and management of forest ecosystem in the reserve. [Ch, 4 fig. 5 tab. 36 ref.]