Effects of Limited Irrigation on Physiological Characteristics and WUE of Winter Wheat

According to a limited irrigation experiment conducted in dry land field at different growth stages of winter wheat,the influence of different water supply treatments on the soil water changes,plant height,leaf area index,photosynthetic characteristics,yield and water use efficiency(WUE).The results showed that: ① with the increase of irrigation quantity,the influence depth of soil layer becomes deeper and soil water changes decrease with the soil depth increasing;② the irrigation on anthesis has a significant compensation effect on leaf area index and plant height under water stress.③ The tendency of diurnal variation of photosynthetic characteristic of every water supply treatment is the same.The transpiration rate and stomatal conductance both present a form of bimodal curve and the diurnal variation of photosynthetic rate single peak curve and midday depression is obvious.④ Flowering water is beneficial to form grain and higher yield can be achieved only by supplying water on anthesis;and it showed a parabola relationship between yield and the total irrigation volume.⑤ The water use efficiency of single leaf and yield vary with the variation of irrigation quantity.The irrigation water use efficiency and water use efficiency decrease with the total irrigation volume increasing but leaf water use efficiency increase with it.⑥ Comprehensive consideration,it is most reasonable to supply water of 75 mm on anthesis during the whole growth period.