Abstract:The effect of nitrogen on the high production of winter wheat by 15N-tracer techniquewas conducted in 1988～1990.The experimental results showed that the yield increase pro-moted by N fertilizer is not only dependent on the increase of N utility and the decrease of Nloss,but also on the effect of N on the grain yield of winter wheat.In Shandong province,187.5kg N per hectare(1/3 for basal dressing and2/3 for spring dressing)s found to be thebest application method.By using this technique, the yield of 7747.5kg/ha and 8251.5kg/haare obtained respectively in the two-year plot-experiments.