Author(s)

Pascal Nsengumuremyi^1,2, Junfang Cui^1*, Ruxin Yang^1,2

¹Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China.
²University of Chinese Academy of Sciences, Beijing, China.

This study investigated the effect of rock fragments on tracer transport in broadleaved and coniferous forest soils from the 0 - 100 cm depth of Gongga Mountain in eastern margin of Qinghai Tibetan Plateau. Using repacked soil columns (20 cm in height and 10 cm in diameter) with different rock fragments contents (0%, 5%, and 15% in v/v), breakthrough curves of bromide (as non-reactive tracer) were obtained under saturated condition. A two-region model was applied and the parameters were estimated by inverse modeling. Results show that with increasing rock fragment content the dispersivity (λ) generally increased while the mobile-immobile partition coefficient (β) and the mass transfer coefficient (ω) decreased. The presence of rock fragments led to an increase in the fraction of immobile domain as well as soil tortuosity. A plausible explanation is that the soil beneath the rock fragments behaved as immobile domain and soil-rock interfaces could serve as preferential flow paths.

Rock Fragments, Forest Soil, Tracer Transport, Breakthrough Curve, Bromide

Nsengumuremyi, P. , Cui, J. and Yang, R. (2021) Effect of Rock Fragments on Tracer Transport in Broadleaved and Coniferous Forest Soils: Column Study. Journal of Water Resource and Protection, 13, 198-215. doi: 10.4236/jwarp.2021.133012.