Effects Of Water And Nitrogen Regulations On Root Growth, Water And Nitrogen Use Efficiency Of Winter Wheat

Water and fertilizer are two important environmental factors affecting crop growth in agricultural production.The vast majority of water and nutrients which are necessary for the growth and development of winter wheat is absorbed thought root system.The root plays an important role on wheat growth,physiological functions and material metabolism process.Therefore,the research on root system distribution and growth condition of winter wheat has great significance for improving the water use efficiency of winter wheat and promoting the coordinated development of environment and agriculture.In order to provide practical guidance for saving water and fertilizer of winter wheat in the condition of limited resources,the effects of different water and nitrogen regulation on water use efficiency,nitrogen use efficiency,physiological and ecological characters of root and grain yield of winter wheat were studied with experiments and theoretical analysis.The main results were as follows:1.The population with N1 and N2 treatments was significantly higher than N0 treatment at over-winter stage,jointing stage and heading stage Under the same nitrogen application,the population with W1 treatment were higher than W0 at over-winter stage,jointing stage and heading stage.The SPAD with different treatments at different growth stage was N1 > N2 > N0.The SPAD at flowing and maturity stage was W1 > W0.2.The moderate nitrogen fertilizer and full irrigation increased spikelet fertile number,thousand kernel weight and grain yield under the rhizobox.Grain yield with different nitrogen treatment was N1 > N0 > N2.Under the same nitrogen treatment grain yield with W1 treatment was higher than that with W0.N1W1 had the highest production.3.With the advancement of growth period,root weight density,root length density,average root diameter,root surface area and root volume of the winter wheat reach the maximum at heading stage,jointing stage the second,filling stage the third.The aforesaid root parameters were largest under treatment N1.Under the same nitrogen application,the root parameters with W1 treatment were greater W0 treatments.Applying nitrogen fertilizer significantly improved the root parameters in the surface soil.4.With different water and nitrogen treatment,there was distinct difference between translocation of dry matter before anthesis and accumulation of dry matter after anthesis with different water and nitrogen treatments.Translocation amount and proportion of dry matter and dry matter contribution proportion were highest with treatment N1W0.Accumulation of dry matter and dry matter contribution proportion after anthesis was highest with treatment N0W1.Nitrogen translocation amount before anthesis was N1 > N2 > N0.Nitrogen accumulation after anthesis was N1 > N0 > N2.Both nitrogen translocation amount anthesis and nitrogen accumulation after anthesis were W1 > W0.5.With the same water treatment,water use efficiency and irrigation water efficiency and precipitation water use efficiency reach the maximum with N1 treatment,N0 the second,N2 the third.With the full irrigation treatment,nitrogen use efficiency was N0 > N1 > N2.With the water deficit treatment,nitrogen use efficiency was N0 > N2 > N1.With the same nitrogen treatment,nitrogen use efficiency and precipitation use efficiency was W1 > W0,and water use efficiency and irrigation water efficiency was W1 < W0.Therefore,under the conditions of this study,the N1W1 treatment improved the root parameters of winter wheat,nutrient uptake and translocation,water and nitrogen use efficiency and grain yield.