Abstract: The purposes of this study were to explore the appropriate nitrogen dressing schedule under fruit and cotton intercropping and provide the theoretical basis about the rational nitrogen application for intercropping cotton field. The experiment material was the central cotton No.49 and performed without shade (CK) and with 50% shade,and three nitrogen dressing schedules,i.e. the N₁ (nitrogen dressing forward),N₂ (normal nitrogen topdressing) and N₃ (the proportion of nitrogen dressing forward was higher than that of N₁),were designed for each treatment so as to explore the effects of nitrogen dressing on the photosynthetic characteristics and yield of cotton in shade under drip irrigation under mulch. The results showed that the chlorophyll content and leaf area index of cotton plant in 50% shade were increased,the net photosynthetic rate was decreased,the proportion of bolls before hot summer days was decreased,and the proportion of autumn bolls was increased compared with those in CK. Under 50% shade,the photosynthetic rate of cotton plant under nitrogen dressing forward (N₁) was appropriately increased,the formation and accumulation of photosynthetic products were promoted,the proportion of bolls before hot summer days was increased,and the bolls per plant,weight per boll and lint yield were significantly increased. Therefore,the nitrogen dressing forward (N₁) could be considered as an effective way to improve the efficiency of solar energy utilization and cotton yield under fruit and cotton intercropping.

Key words: cotton, shade, nitrogen fertilizer, photosynthetic characteristic, yield