Effects Of Nitrogen Application On Grain Yield And Quality As Well As Nitrogen Use Efficiency In Wheat Cv. Yangmai 10

The effects of nitrogen application on grain yield, quality and nitrogen use efficiency in Tr.aestivum L.cv.Yangmai 10 were studied on the Experiment Field of Crop Cultivation and Physiological Key Laboratory of the Ministry of Agriculture,Yangzhou University from 2000-2001.The main results were as follows.(1)The amount of nitrogen application and the ratio of basal to top dressing nitrogen could significantly regulate grain yield and yield components.The nitrogen application amount had a quadratic curve correlation with yield and the optimum nitrogen amount was 266.55kg/ha. Under the same amount of nitrogen.the ratio of basal to top dressing nitrogen 5:5 could get the highest yield , 4:6 took the second place.(2) In a appropriate range of nitrogen application amount, grain protein and gluten contents increased with the total amount of nitrogen fertilizer. Under the present experiment condition, protein content rose from 10.99% to 13.29% and wet gluten content from 25.28% to37.51%. With the same nitrogen amount, increasing top dressing percentage could increase protein and gluten contents.There was a quadratic curve correlation between grain protein yield and total nitrogen amount,and the optimum nitrogen amount was 307.88kg/ha.(3)There was a significant positive correlation between the accumulated nitrogen amount at elongation stage and applied N before sowing. During the period from elongation to anthesis,there was a significant positive correlation between nitrogen accumulation amount and the amounts of total and top dressing nitrogen.Afteranthesis ,the nitrogen accumulation quantity had a significant positive correlation with top dressing N,and a quadratic curve correlation with the total amount of applied nitrogen. Within the appropriate range of total nitrogen amount increasing nitrogen could enhance nitrogen accumulation capacity after anthesis.The exported amount of nitrogen from vegetative organs to grains had a significant positive correlation with the basal nitrogen amount, while had a quadratic curve correlation with the total applied nitrogen. Under the suitable amount of total nitrogen,increasing basal nitrogen amount could enhance the exportation of nitrogen to grains.Under the appropriate total nitrogen amount, increasing top dressing percentage could raise grain protein and gluten contents.(4)Nitrogen fertilizer use efficiency had a quadratic curve correlation with the total amount of nitrogen fertilizer. When total nitrogen was less than 161.25kg / ha .the efficiency increased with nitrogen amount. Total nitrogen fertilizer utilization efficiency could increase to 41% with the total nitrogen amount of 69.79-252.72kg / ha. The ratio of basal to top dressing could also affect nitrogen fertilizer utilization efficiency.Under the same amount of nitrogen .the order of nitrogen use efficiencies in different basal :top dressing nitrogen treatments was 6.3:3.7<3.7:6.3<5:5.(5) With total nitrogen ranging from 206kg/ha to 252kg/ha, basal:top dressing 5:5 treatment resulted in a grain yield more than 6750kg/ha ,and nitrogen use efficiency greater than 41%, which was a high-yielding and high- efficient treatment.With the nitrogen amount of 266Kg/ha to 307kg/ha , basahtop dressing nitrogen 4:6 treatment could get a grain yield over 6750kg/ha and grain protein content above 12.18%, resulting in high yield and good quality.