Work

Preferential flow in soils is key to the development of nebkhas in water limited regions

Year: 2025

Type: article

Abstract: • As “fertile islands”, nebkhas have better soil structure and higher nutrients content than bare sand dunes. • Infiltration pattern in nebkha was dominated by preferential flow, while matrix flow was predominant in bare sand dune. • The degree of preferential flow was increased with the success of nebkha especially under low precipitation condition. • Soil organic content, total porosity and root biomass were all contributed to the development of preferential flow of nebkhas. • Higher degree of preferential flow of nebkhas might an important strategy for nebkhas to adapted extreme arid environments. Nebkhas, a typical landscape form in arid and semiarid environments, play important roles in desertification control and biodiversity protection. However, water use strategies and infiltration characteristics of nebkhas change with their development stages in regions with low precipitation and deep groundwater, and those changes are not well known. Here, we investigated changes in soil properties and quantified preferential flow characteristics with a dye tracer experiment in nebkhas at different development stages including bare sand dunes (BD), and small (SN) and large nebkha (LN) in different precipitation conditions. Our results showed that soil properties such as clay and silt content, organic carbon content, total porosity, and soil crust thickness increased with nebkha development stages (BD < SN < LN), indicating that soils in LN had better soil structure and physicochemical properties than those in BD. The degree of preferential flow was highest in LN, intermediate in SN, and minimal in BD, and it decreased with an increase in precipitation. Infiltration patterns in SN and LN were dominated by preferential flow, while matrix flow dominated in BD. Higher soil organic matter content, total porosity, and thickness of the soil crust in LN all significantly contributed to the development of preferential flow in nebkhas especially under low precipitation conditions. We conclude that a higher degree of preferential flow in nebkhas may enhance their rainwater infiltration capacity and that represents a very important strategy in nebkha adaptation to extremely arid environments.

Source: Geoderma

DOI: 10.1016/j.geoderma.2025.117205

Authors: Weicheng Luo, Wenzhi Zhao, Ning An, Chengpeng Sun, Hong Zhou

Institutions: Chinese Academy of Sciences, Northwest Institute of Eco-Environment and Resources, University of Chinese Academy of Sciences, Yantai Vocational College, Northwest Normal University

Language: English

Topic: Soil and Unsaturated Flow

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Life on land

Open Access status: gold

Estimated APC paid: $3,320