© 2006 Heron Publishing—Victoria, Canada
Electrical measurement of the absorption surfaces of tree roots by the earth impedance method: 1. Theory
Ludek Aubrecht (1, 2), Zdenek Stanek (1) and Jan Koller (1)
1. CTU in Prague, Faculty of Electrical Engineering, Department of Physics, Technicka 2, 166 27 Prague 6, Czech Republic / 2. Corresponding author (aubrecht@fel.cvut.cz) / Received March 14, 2005; accepted September 8, 2005; published online June 1, 2006
Summary
Analysis of plant root systems is difficult under field conditions, especially root systems of adult trees, which are large
and complex and include fine absorbing roots as well as conducting coarse roots. Although coarse roots can be visualized by
several methods, there are technical difficulties with root quantification. The method presented here focuses on the quantification
of absorbing root surfaces through an electrical (the modified earth impedance) method. It is based on the experimentally
verified fact that an applied electric current flows from the roots to the soil (or vice versa) through the same interfacial
areas and predominantly in the same way as water (water solution of minerals or nutrients) flows from the soil to the tree.
Based on the different conductivities of tree tissues and soil, the interfacial area, which represents the absorbing root
surfaces (or root absorption zones), can be calculated. Only the theoretical description of the method is presented in this
paper: the experimental verification of the method under field conditions is presented in the accompanying paper.
Keywords:
absorbing root surfaces, absorption zones, electrical resistivity and conductivity, four-point method.
