Some chemical and eletrochemical kinetics and the equilibria of CdCO₃ and CdS in soil solution were investigated under the condition of additional Cd,P and Zn compounds.Suhmergence brought about a series of physicochemical and chemical changes that markedly influenced the pH,Eh,EC,Es,chemical kinetics and mineral equilibrium in paddy soils.The pH of soil solution gradually increased while Eh decreased with the time of soil flooding.Some of Cd treatments decreased Eh.The maximum EC value reached at 4th week after flooding and then declined gradually.The concentrations of NH₄⁺-N,K,Ca,Mg,Fe and Mn in soil solution increased markedly during first 2 to 4 weeks after flooding,while those of Zn and P were getting decreased.A study of CdCO₃ and CdS equilibria by means of IAP method showed that there might be CdS present in the soil after 5 weeks of submergence.But results gave no thermodynamic evidence fur CdCO₃ existence.