redistribution of soil water by tree root systems

• Published in: Oecologia 1998-07, Vol.115 (3), p.306-311
• Main Authors: Burgess, S.S.O, Adams, M.A, Turner, N.C, Ong, C.K
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Autoecology; Biological and medical sciences; Ecophysiology; Eucalyptus camaldulensis; Forest soils; Fundamental and applied biological sciences. Psychology; Grevillea robusta; Hydraulics; Plant roots; Plants; Plants and fungi; Root systems; roots; Sap flow; Soil depth; Soil hydraulic properties; soil profiles; Soil water; Soil water movement; water uptake
• ISSN: 0029-8549; 1432-1939
• DOI: 10.1007/s004420050521

Plant roots transfer water between soil layers of different water potential thereby significantly affecting the distribution and availability of water in the soil profile. We used a modification of the heat pulse method to measure sap flow in roots of Grevillea robusta and Eucalyptus camaldulensis and demonstrated a redistribution of soil water from deeper in the profile to dry surface horizons by the root system. This phenomenon, termed "hydraulic lift" has been reported previously. However, we also demonstrated that after the surface soils were rewetted at the break of season, water was transported by roots from the surface to deeper soil horizons -- the reverse of the "hydraulic lift" behaviour described for other woody species. We suggest that "hydraulic redistribution" of water in tree roots is significant in maintaining root viability, facilitating root growth in dry soils and modifying resource availability.