Vol.:(0123456789) 1 3 Journal of Soils and Sediments https://doi.org/10.1007/s11368-022-03375-w SOILS, SEC 5 • SOIL AND LANDSCAPE ECOLOGY • RESEARCH ARTICLE Linking roots, preferential flow, and soil moisture redistribution in deciduous and coniferous forest soils Ziteng Luo 1,2  · Jianzhi Niu 2,3  · Shuqin He 1  · Linus Zhang 4  · Xiongwen Chen 5,6  · Bo Tan 1  · Di Wang 2  · Ronny Berndtsson 4 Received: 26 July 2022 / Accepted: 28 October 2022 © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2022 Abstract Purpose Soil moisture (i.e., the changes in the gravimetric soil water content) redistribution is closely linked with root dis- tribution and preferential flow in soils. This study aimed at exploring the soil water content distribution in the presence of root-enhanced preferential flow in deciduous (Quercus variabilis BI.) and coniferous forests (Platycladus orientalis (L.)). Methods Dual-tracer experiments (Brilliant Blue FCF and Bromide [Br − ]) were conducted in both forests under large (40 mm) and extreme (70 mm) rainfall amount. The distribution of soil water contents was investigated in vertical soil pro- files after dual-tracer experiments. Additionally, the correlations among soil water contents, root traits (diameter ≤ 5 mm), and preferential flow features (preferential flow paths and root-solute interaction) were analyzed. Results Abundant root-induced soil moisture accumulation was found in the upper soil layer (0–20 cm), which was more apparent in deciduous forest than in coniferous forest. Preferential flow strongly influenced the variation distribution of soil water content. The greater degree of preferential flows was, the higher soil water content was. In both forests, the effect of root traits on soil water distribution was more evident under large rainfall amount as compared to extreme rainfall amount. In addition, positive significant correlation between root-solute interaction and soil water content was found at both sites. Conclusions These results indicated that tree species with different roots distribution patterns enhance different degree of preferential flow, and have varied impacts on the soil moisture redistribution in forest soils. The effects of root traits on soil moisture are more apparent under lower rainfall amount. Keywords Roots · Dual-tracer experiment · Preferential flow · Soil moisture · Forest Responsible editor: Xiaoqi Zhou * Jianzhi Niu nexk@bjfu.edu.cn * Shuqin He angelhsq@163.com 1 National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River, Sichuan Province Key Laboratory of Ecological Forestry Engineering on the Upper Reaches of the Yangtze River, Soil and Water Conservation and Desertifcation Control Key Laboratory of Sichuan Province, College of Forestry, Sichuan Agricultural University, 211 Huimin Road, Chengdu, Sichuan 611130, China 2 Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Engineering Research Center of Soil and Water Conservation, Engineering Research Centre of Forestry Ecological Engineering, Ministry of Education, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China 3 Beijing Collaborative Innovation Center for Eco-Environmental Improvement With Forestry and Fruit Trees, Beijing 102206, China 4 Division of Water Resources Engineering & Centre for Advanced Middle Eastern Studies, Lund University, Box 118, Lund SE-221 00, Sweden 5 Department of Biological and Environmental Sciences, Alabama A&M University, Normal, AL 35762, USA 6 Jiyang College, Zhuji, Zhejiang 311800, China