抄録
Nitrogen management and cover cropping are key strategies for improving maize productivity and nitrogen use efficiency, yet their interactive effects on photosynthetic regulation and yield formation remain insufficiently understood. A two-factor field experiment was conducted to investigate how different cover crops and nitrogen supply levels jointly regulate maize photosynthetic performance, canopy development, and yield formation. The results showed that cover crops significantly enhanced photosynthetic capacity and canopy light-use efficiency under low nitrogen conditions, thereby promoting biomass accumulation and kernel set. Under moderate to high nitrogen supply, cover crops improved photosystem II efficiency, delayed leaf senescence, and sustained grain filling, resulting in greater yield potential. Significant interactions between cover cropping and nitrogen supply indicated that yield improvement was primarily driven by the coordinated enhancement of leaf photosynthetic efficiency, canopy architecture, and nitrogen use efficiency rather than by increased nitrogen input alone. These findings demonstrate that optimizing cover crop–nitrogen management synchronizes photosynthetic carbon assimilation with nitrogen utilization, providing a physiological basis for improving maize productivity and resource-use efficiency under sustainable cropping systems.
