Electric resistance-capacitance model of water flow through soil-plant system
土壤-植物系统水分运移过程的阻容电模拟

Water flow through a soil-plant system can be simulated by an electric resistance-capacitance circuit when the flow is considered as one-dimensional Darcy-Rechards flow.The hydraulic resistance is a ratio of the water potential difference to the average rate of outflow and inflow,and the water capacitance is a derivative of the water storage with respect to the average water potential because of the nonsteady nature of water transport.Corresponding to the Darcy-Richards equation,hydraulic resistance and resistivity are the reciprocals of conductance and conductivity respectively;time constant is the reciprocal of the diffusance;and time constant per unit squared length is the reciprocal of diffusivity.If the soil-plant system is taken as a catenary series of segments along the water flow path,the hydraulic resistance and water capacitance are connected in parallel with each other in each segment,and all segments are connected in series.The study gave universal formula of water flow through the soil-plant systems,formula of the relationship between the total capacitance and partial capacitances of individual segements,formula of the relationship between the total resistance and partial resistances,and formula of temporal change of leaf water potential under a certain condition.