### Different of soil carbon sequestration between rhizosphere and bulk soil in a mountain coniferous forest in Southwestern China under nitrogen deposition

Ying ZHANG1,changhong zhang1,Qi-Tong WANGxiaomin zhu3,Hua-Jun YIN4

• Received:2022-05-19 Revised:2022-10-12 Published:2022-11-02
• Contact: Qi-Tong WANG

Abstract: Aims Due to complex root-soil interactions, the responses of carbon (C) dynamics in the rhizosphere soil to nitrogen (N) deposition may be different from those in bulk soil. However, the potentially different response of C dynamics in the rhizosphere and bulk soil and their contributions to soil C sequestration under N deposition is still not elucidated. Methods In this study, a typical subalpine coniferous plantation (Picea asperata) with chronic N addition treatments in southwestern China was selected as the research object. Based on the experimental plots of simulated N deposition (control: 0 kg·hm–2·a–1; N addition: 25 kg·hm–2·a–1), which established by our research team in the early stage. We measured the content of soil organic carbon and its different fractions, then combined with the rhizosphere spatial numerical model, and quantified quantification and comparison C pool size of SOC and its fractions in rhizosphere and bulk soil. On the basis, effect on soil C sequestration in rhizosphere soil under N addition were evaluated. Important findings The results showed that the rhizosphere and bulk soil of coniferous forest in southwestern mountainous area had great C sequestration potential under N deposition, and the C sink effect of rhizosphere soil was more obvious. Our research results highlight the importance of integrating rhizosphere processes into land surface models to accurately predict ecosystem functions against the background of increasing N deposition.