Rock fragments significantly affect the carbon and nitrogen distribution in the surface soil - Evidences from large number samples of soil rock fragment interfaces in a boreal forest watershed

Jinhao Zhang; Yushan Cai; Liangliang Duan

doi:10.1016/j.scitotenv.2024.171640

Rock fragments significantly affect the carbon and nitrogen distribution in the surface soil - Evidences from large number samples of soil rock fragment interfaces in a boreal forest watershed

Sci Total Environ. 2024 May 15:925:171640. doi: 10.1016/j.scitotenv.2024.171640. Epub 2024 Mar 11.

Authors

Jinhao Zhang¹, Yushan Cai¹, Liangliang Duan²

Affiliations

¹ College of Forestry, Northeast Forestry University, Harbin 150040, China; Key Laboratory of Sustainable Forest Ecosystem Management, Ministry of Education, Northeast Forestry University, Harbin 150040, China.
² College of Forestry, Northeast Forestry University, Harbin 150040, China; Key Laboratory of Sustainable Forest Ecosystem Management, Ministry of Education, Northeast Forestry University, Harbin 150040, China. Electronic address: liangliang.duan@nefu.edu.cn.

PMID: 38479530
DOI: 10.1016/j.scitotenv.2024.171640

Abstract

Rock fragments are widely distributed in soils. The material cycling and the physico-chemical processes of soil ecosystems are both inevitably spatially affected by rock fragments. However, the effect of rock fragments on the spatial distribution characteristics of soil carbon and nitrogen is still not well studied and understood. We carried out a study on the effect of rock fragments on the spatial distribution of soil carbon and nitrogen by mass sampling at the interfaces of rock fragments in a boreal forest watershed ecosystem of northest China. We found that the carbon and nitrogen content of rock fragments interface soil (SRIS) was significantly lower than that of general soil (GS). The content of total soil carbon (TC) and total soil nitrogen (TN) in 0-20 cm SRIS accounted for 73 % and 43 % of those in the GS, respectively. The content of TN in 20-40 cm SRIS was about 43 % of that in the GS. The results of Random Forest Model and Pearson correlation analysis (P < 0.01) indicated that the soil water content (SWC) and soil machinery composition (SMC) contributed most to the variabilities of soil carbon and nitrogen. We also found significant differences in SMC between GS and SRIS. Such evidences suggested that the presence of rock fragments was expected to promote the loss of soil carbon and nitrogen，and consequently influence soil carbon and nitrogen distribution nearby them. Our findings help improve the understanding of the impact of rock fragments on soil carbon and nitrogen distribution and provide new insights into the participation of rock fragments in the material-energy cycle of ecosystems.

Keywords: Rock fragments; Soil carbon and nitrogen; Soil machinery composition; Soil-rock fragment interface.