Abstract: To study the effects of different combinations of nitrogen,phosphorus,potash,organic fertilizers and irrigation on winter wheat yields,the field experiments were conducted in Changping,Beijing from 2007 to 2008.The results showed that the effects of each factor was nitrogen>irrigation>potassium>organic fertilizer>phosphorus,and interaction was still existed.There was positive correlation between irrigation and yields.Organic fertilizer had a significant relationship with yields,though its effect was less than nitrogen fertilizer,potash fertilizer and irrigation.The most optimum treatment was 75kg/ha nitrogen,12000kg/ha organic fertilizer,75kg/ha phosphorus,150kg/ha potassium and 3000kg/ha irrigation.

Key words: Combined application of nitrogen, Combined application of nitrogen, phosphorus and potassium fertilizers, Irrigation, Organic fertilizer, Winter wheat yield