PROBLEM TO BE SOLVED: To provide a method for measuring earthing resistance of plants, eliminating the influence of electrode resistance on electrodes set on plant stems or trunks, and also eliminating the influence of electrical resistance on the plant stems or trunks themselves so as to enable measurement of earthing resistance. SOLUTION: The method for measuring earthing resistance comprises the following process: setting a main electrode T for turning on electricity on the ground surface in the vicinity of a tree 1 rooting the ground 2, setting an auxiliary electrode C for turning on electricity on the ground apart from the tree 1, mounting a first electrode E for electrometry at the upper part of the main electrode T set on the tree 1, mounting a second electrode P for electrometry on the ground between the main electrode T and the auxiliary electrode C, energizing measuring current i flowing through the ground 2 via the root of the tree 1 between the main electrode T and the auxiliary electrode C, measuring the potential difference ex between the first electrode E and the second electrode P, dividing the potential difference ex by the measuring current i to obtain earthing resistance Rr between the root of the tree 1b and the ground 2. COPYRIGHT: (C)2003,JPO
