Abstract:The effects of N,P and organic fertilizers and their interactions on the yield and its components,photosynthesis rate of leaves in different leaf locations,main stems and tillers,and grain quality of winter wheat(Shaan 512) were studied.The results showed that fertilization could strongly influence the photosynthetic rates.A significant difference in photosynthesis rate was found between different treatments and leaf and shoot locations at the late booting stage and significant interaction between treatments and different leaves at the flowing stage.Applying N and P together with the organic fertilizer significantly increased the photosynthetic rates of functional leaves,in which N135P120S375 showed the best results on photosynthesis,which increased photosynthetic rates of the flag and penultimate leaves by 30.9% and 21.9%,of functional leaves of main stems by 21.8%,and of the primary and secondary tillers by 36.6% and 28.3% compared to CK.It also increased the numbers of the secondary roots by 12.5%-28.3%,and of tillers by 11.1%-29.7% compared to CK.It could also improve grain quality,i.e.it increased stable time by 80.3%,protein content by 4.1%,while it reduced falling number by 6.1%,water absorption by 7.2%.It increased heads by 6.3%,while it reduced grains per head by 4.0%,and yield increased by 5.2% compared to CK.