Research On Effect Of Different Water And Nitrogen Supply On Growth, Yield And Quality Of Winter Wheat

Water and nitrogen plays a vital role in the growth process of winter wheat, however,nowadays we face a serious problem that is the shortage of water resource and spatial andtemporal uneven distribution. In order to protect our food security and sustainableagricultural development, this study intend to provide a water and fertilization saving,steady yield and good quality mode for winter wheat. This experiment was carried in thekey laboratory for Agricultural Soil and Water Engineer in Arid Area of Ministry ofEducation, Northwest A&F University during October2010to June2011. In this paper, thegrowing index, yield and quality of the winter wheat, water consumption, water useefficiency and the absorption of NO3-N in soil were monitored and analyzed in both fieldand pot treatment. The following results are got:(1) According to the study of growing index in different water and nitrogen treatment,the results showed: proper water and nitrogen supply can promote the growth of plant. Theheight of winter wheat increased with irrigation water content increasing, while firstincreased then decreased with the amount of nitrogen increasing, the critical value ofnitrogen were120kg/hm~2and0.2g/kg in field and pot. Nitrogen is the main effect factor ofheight before the jointing stage, the height difference among different treatment was mainlycaused by both water and nitrogen in the jointing stage, while in the grain filling stage wascaused by the interaction of the two factors. Leaf chlorophyll content and leaf area showedthe same tends, they both first increased and then decreased. The difference is that themaximum leaf area was in the heading stage, while the maximum leaf chlorophyll was inthe late jointing stage. Leaf area increased with the irrigation volume increasing, while inthe different nitrogen treatment, it showed middle nitrogen treatment higher than highnitrogen treatment higher than low nitrogen treatment. The impact of irrigation on thechlorophyll content, chlorophyll was very small, it increased slightly with the increase ofirrigation, proper nitrogen (120kg/hm~2in field and0.2g/kg in pot) can help delay leaf senescence and increase the photosynthesis time which was in favor of photosyntheticproduction.(2) According to the study of yield and quality in different water and nitrogentreatment, the results showed: the growth rate of accumulation of dry matter showed"slow-fast-slow" trend, and the accumulation in high water and high nitrogen treatment washigher than that in low water and low nitrogen treatment. The yield of winter wheat firstincreased and then decreased, when the irrigation over the amount which the plant needs,the water can not be used which not only waste water but also excess water can inhibit theyield. The yield of winter wheat increased with the increasing of nitrogen content. The grainprotein content and irrigation content were negatively correlated, while positively correlatedwith nitrogen content. On the contrary, the starch content increased with water contentincreasing, decreased with nitrogen content increasing. In short, select middle water andnitrogen treatment is the best.(3) According to the study of water use efficiency in different water and nitrogentreatment, the results showed: water and nitrogen played a significant impact to crop waterconsumption and water use efficiency, and the interaction effect of these two factors wasobvious. The water consumption increased with the irrigation content increasing, however,the water use efficiency decreased with the increasing irrigation volume and increased withthe increasing nitrogen volume.(4) According to the study of nitrogen use efficiency and inorganic nitrogen in soil indifferent water and nitrogen treatment, the results showed: the nitrogen content in the cropincreased through the growth period, and the accumulation in the early stage was greaterthan that in late stage, it increased with the increasing water and nitrogen content. The nitricnitrogen content in soil first decrease and then increase with the increasing of soil depth.The nitric nitrogen content increased with the increasing nitrogen content, and the trend ofmoving down was obvious, however, it had no difference in different irrigation treatment.The nitrogen use efficiency decreased with the increasing irrigation and showed the trend offirst increase and then decrease with the increasing nitrogen, the critical value of nitrogen is120kg/hm~2. In this study, the nitrogen consumption of each plant in treatment of W2N2was0.15～0.225g, at this time, the yield can got the highest level and the nitrogen use efficiencycan also achieve a high level, was the best choice in practice.