| Winter wheat is the major crops in China. Drought and water shortage is the most important limitingfactor for wheat production in northern China, and regulated deficit irrigation is important irrigationtechnology to develop the water-saving agriculture. However, the current research on regulated deficitirrigation is mostly biased towards individual effect of water, lacked depth study for effect of regulateddeficit irrigation under different nitrogen treatments. In this study, field trials were conducted to study theeffect of different nitrogen application on regulated deficit irrigation of winter wheat. Use Aikang58asexperimental material, it is planted in most of Huanghuai Plains of China. There are two nitrogentreatments, named N1(topdressing nitrogen ratios10:0) and N2(topdressing nitrogen ratios6:4), andtopdressing nitrogen at jointing stage; water regulated deficit stage was returning green-jointing stage,plants were maintained at50-55%FWC (field water capacity) at this stage, adequate supplies (plants weremaintained at70-75%FWC) as contrast. Each treatment material divided into two groups after headingstage, the first group to keep about75%FWC; the second group was the progressive soil dying condition.D stand for water deficit and W stand for adequate water supply. The main results are as follows:1. Water deficit treatment at returning green-jointing stage reduced LAI (leaf area index), plant heightand the population of winter wheat significantly, but it had no significant effect on photosynthesis of winterwheat leaves; rewatering after heading stage, regulated deficit irrigation of winter wheat had compensationeffect on physiological and growth process. Under the progressive soil dying condition after heading stage,N2treatment can improve photosynthesis in flag leaves of winter wheat in the late growth stage.2. Water deficit treatment at returning green-jointing stage could improve root vitality of winter wheat,it could show a longer aftereffects under well-water condition in the late growth stage, could reduce the rateof accumulation of MDA in flag leaves and maintain a high POD activity in flag leaves in the late growth stage. Under the progressive soil dying condition after heading stage, N2treatment could improve rootvitality of winter wheat in the late growth stage and reduce the content of MDA in flag leaves, it also couldimprove POD activity in flag leaf, then delaying senescence in flag leaf, so increased drought resistance ofwinter wheat.3. Under well-water condition after heading stage, water deficit treatment at returning green-jointingstage could promote dry matter distribution to grains, laid the foundation for the formation of grain yield.Under the progressive soil dying condition after heading stage, N2treatment can increase dry matteraccumulation after anthesis and contribution rate after anthesis to grains, all of these could improve grainyield.4. Whatever the water condition is good or not of winter wheat in the growth stage, water deficittreatment at returning green-jointing stage was conducive to transport nitrogen from vegetative organs tograin, and N2treatment could improve nitrogen translocation amount and nitrogen translocation efficiency;water deficit treatment at returning green-jointing stage was conducive to improve nitrogen harvest index.5. Under well-water condition after heading stage, water deficit treatment at returning green-jointingstage significantly improved on grain yield of winter wheat. Under the progressive soil dying conditionafter heading stage, N2treatment can increase grain yield of winter wheat. Yield stability of N2treatmentwas higher than N1treatment proved that topdressing nitrogen at jointing stage can improve droughtresistance of winter wheat. Water deficit treatment at returning green-jointing stage could increaseirrigation water use efficiency of winter wheat significantly, it was also conducive to water use efficiency ofwinter wheat under well-water condition after heading stage. |
