The present article deals with thp study of K⁺ status in rhizosphere soil of cotton,barley and vetch by means of the potassium selective microelectrode and frozen slice methods.It was found that there were some factors affecting the either accumulation or depletion of K⁺ in rhizosphere soil of plants.The moisture content of soil was the main factor to induce the change of K⁺ status.When the moisture content was lower than the field moisture capacity,there appeared a depletion gradient in thizosphere.On the contrary,while it was hieher than the field moisture canacitv,an accumulation zone occured.