Effects of soil moisture of root zone on root growth and yield of spring wheat under drip irrigation

Through water controlled trial in root zone under drip irrigation,the effect of different soil moisture on vertical distribution of roots,yield components and water use efficiency of spring wheat were studied.The results showed that booting-flowering was a critical period of spring wheat root growth and most roots were distributed within soil layer of 0～40 cm under drip irrigation.The distribution of root length density and root dry weight showed decreasing trend of negative index with soil depth which could fit by y=A×exp(-Bx);The effect of soil moisture in root zone on growth and distribution of root was significant.Limited irrigation treatment had a higher proportion of deep soil root volume,but root dry weight decreased significantly.Excessive irrigation had a largest root volume which mainly concentrated in shallow soil,that easily lead to lodging,and the proportion of assimilated matter distributed to spike was lower.Root distribution of appropriate irrigation treatment was more reasonable,whose root length,root surface area and root dry weight density maintained a high level in the filling stage,and single spike weight and WUE were significantly higher than that of limited amount treatment and excessive amount treatment,so its yield was the highest;By drip irrigation to control water status in wheat root zone,it can be achieved to promote formation of higher yield and to obtain higher efficiency of water use efficiency.