Abstract: In order to determine the wheat straw residue amount and the nitrogen fertilizer amount in the dry land，different amounts of straws returned to field and nitrogen treatments were set up in Qingdao agriculture university Jiaozhou experiment stations． We researched the effects of precise straw returned quantity and nitrogen fertilizer treatments on winter wheat photosynthetic characteristics and yield． The results showed that compared with only nitrogen fertilizer treatment， right amounts of straws returned to field can improve winter wheat chlorophyll SPAD value obviously，delay senescence of flag leaf， improve the photosynthetic performance of flag leaf and increase the 1000-seed weight． In the same level of the straw returned to N2 level of the flag leaf senescence winter wheat slowly，and photosynthesis prolonged， the yield was increased significantly． Straw returned 9 000 kg /ha( J3) under 225 kg /ha ( N2) nitrogen can delay senescence of flag leaf， improve the photosynthetic performance of flag leaf， reduce stomatal conductance and increase the 1000-seed weight obviously compared with other process，however，wheat straw reduced the wheat effective panicles． The experimental results showed that straw returned 9 000 kg /ha under 225 kg /ha nitrogen dosage had the most obvious effect on improving photosynthesis of flag leaves． So the N2J3 treatment is the optimal choice in the locality．

Key words: Nitrogen fertilizer, Straw-return, Photosynthetic Characteristics, Yield

CLC Number: 

• S143.1

• S316