Abstract:With control group was conventional single nitrogen fertilizer (CK,270 kg·hm-2), a field experiment was conducted to study the effects of organic fertilizer with reducing nitrogen fertilizer on photosynthetic characteristics, nitrogen uptake and grain yield formation of wheat. There were three organic fertilizer treatments and three N application rates in this trial. Organic fertilizer treatments were returning straw to field (J), returning straw with mushroom residue (JZ), returning straw with cattle manure (JF), respectively. N application rates included N1 (90% pure nitrogen of CK), N2 (80% pure nitrogen of CK), N3 (70% pure nitrogen of CK), respectively. The results showed that: (1) compared with CK, organic fertilizer coupled with N application obviously promoted tiller generation and effective panicle number at wheat growth stage, enhanced chlorophyll content and maintained higher level of flag leaf photosynthetic rate, increased dry matter accumulation, nitrogen uptake, grains per spike and 1 000grains weight at growth stage, and significantly increased wheat grain yield by 4.21%-17.80%, and wheat grain yield under JFN2(JF+N2) was up to 6 853.43 kg·hm-2. (2) The effect of N2 (reduced nitrogen fertilizer 20%) was the best in the treatment of the same organic fertilizer, which could significantly promote the formation of wheat population, increase chlorophyll content and photosynthetic rate, yield of wheat; Wheat population at maturity under JFN2 treatment was higher than that under JFN1 and JFN3, increased 5.16% and 4.31%, respectively; Chlorophyll content of wheat at anthesis under JN2 treatment was higher than that under JN1 and JN3, increased 2.29% and 2.31%, respectively; Yield of treatments of JFN2 was significantly higher than that of JFN1 and JFN3, increased 11.41% and 7.56%, respectively. (3) At the same nitrogen application level, dry matter accumulation of wheat at maturity under JZN1 treatment was significantly higher than that under JZN2 and JN2, increased 8.93% and 12.01%, respectively; Nitrogen accumulation of wheat at anthesis under JF treatment significantly higher than that of the other organic fertilizer treatments under three nitrogen application levels, respectively; Yield of JFN2 treatment was significantly higher than that of JZN2 and JN2, increased 12.17% and 6.09%, respectively. It was concluded that appropriate N fertilizer rate combined organic fertilizer enhanced wheat tillering and effective panicle formation, increased chlorophyll content, photosynthetic rate, dry matter accumulation and nitrogen accumulation, and then increased wheat grain yield.