Based on the measured data of soil water potential,leaf water potential, air water potential,and transpiration rate in winter wheat and summer corn fields and the application of them to the Van den Honert (1948) steady-state flow equation,the magnitude, the variation with time and depth, and the relative importance of various resistences to water flow in soil-plant-atmosphere continuum (i.e.SPAC) were estimated.The estimated results indicated that the main resistances to water flow in SPAC take place in the...