Investigation of interactions and energy relationships between cations (Na⁺、K⁺、NH₄⁺、Ca²⁺、Zn²⁺, and Cd²⁺) and clay fraction of red soil with the aid of Wien effect in dilute suspensions Results show that the mean Gibbs binding energies of the clay fraction of red soil with cations are 4.50, 7.35, 7.15, 9.12, 9.84, and 9.63 kJ mol^-1 for Na⁺, K⁺, NH₄⁺, Ca²⁺, Zn²⁺, and Cd²⁺, respectively, in the experimental condition. Electric conductivity increased very fast with field strength in the suspension containing Ca²⁺, at a similar rate in the suspension containing K⁺, Zn²⁺ or Cd²⁺, but very slowly in the suspensions containing Na⁺ or NH₄⁺. In terms of releasing rate, the cations in the red soil suspension are in the order of Ca²⁺ > K⁺ > Zn²⁺ = Cd²⁺ > Na⁺ = NH₄⁺. The mean Gibbs free adsorption energies, ΔG_ad, of the cations remained basically the same when the field strength was in the range of 15 to 80 kV cm^-1 , but when the field strength reached over 100 kV cm^-1 ΔG_ad of the divalent cations were more obviously higher than of the monovalent cations, following an order of NH₄⁺ ≤Na⁺ < K⁺ < Cd²⁺ < Zn²⁺ < Ca²⁺. However, when the field strength got high up to 150 kV cm^-1, ΔG_ad of the cations were 0.64, 0.80, 0.57, 1.66, 1.43, and 1.27 kJ mol^-1 for Na⁺, K⁺, NH₄⁺, Ca²⁺, Zn²⁺, and Cd²⁺, respectively, which shows that the mean Gibbs free adsorption energy of the divalent cations were about 2.5-3 times as much as that of the monovalent cations. The cations in the red soil suspensions at a low field strength ranging from 10 to 30 kV cm^-1 showed a decreasing order of Na⁺ >> K⁺ = NH₄⁺ > Ca²⁺ > Zn²⁺ = Cd²⁺ in mean dissociation degree. The increasing rate of mean dissociation degree, which is the increment of dissociation degree induced by the increment of 1 kV cm^-1 in field strength, is the highest with Na⁺ being 0.000427 cm kV^-1, the second with Ca²⁺ being 0.000221 cm kV^-1, and the lowest with other cations in the range of 0.00012~0.00014 cm kV^-1.