effect of deficit irrigation on bean root water uptake in different depths

more understanding of root water uptake (rwu) can lead us to discharge the irrigation water in soil in a water stress condition. the main objective of this research is measurement of rwu by bean in a water stress condition. a completely randomized design was employed in greenhouse condition concerning four treatments and four replications. the treatments were fi: full irrigation as control, di80: deficit irrigation with 80% of etc, di60 and di50. soil depth divided to four equal layers. rwu calculated by soil water balance technique. the results show that minimum soil water difference observed in layer number four in both fi and di80. the difference was greater in di60 and di50 both in layer number four and three. the maximum rwu was measured 11.8 mm/day in control and it was equal to 5.9 mm/day in di50 as minimum. the average rwu were decreased 8.11, 26.5 and 33.84 percent in di80, di60 and di50, respectively in comparison with the control where it was significant in five percent level. the portion of layer 1 and 2 in rwu was 84.2, 77.36, 70.37 and 63.69 in fi, di80, di60 and di50, respectively.