抄録
Optimizing the coordination between sowing date and nitrogen topdressing is essential for improving yield stability and nitrogen use efficiency in winter wheat, yet the mechanisms underlying their interactive regulation of canopy development and biomass production remain insufficiently understood. A two-factor field experiment was conducted to quantify the independent and interactive effects of sowing date and nitrogen topdressing timing on crop phenology, canopy development, dry matter accumulation, and yield formation. Delayed sowing reshaped crop growth dynamics by shortening the vegetative growth period, thereby altering canopy development, population establishment, and biomass accumulation patterns. Nitrogen topdressing timing regulated canopy functional longevity and assimilate production, with its effectiveness strongly dependent on sowing date. Their interaction significantly influenced canopy development, dry matter accumulation, and final grain yield, indicating that the response to nitrogen management is governed by crop developmental status rather than nitrogen supply alone. These results demonstrate that synchronizing sowing date with nitrogen topdressing optimizes the temporal coordination between canopy development and biomass allocation, thereby enhancing yield formation and nitrogen use efficiency. This study provides a mechanistic framework for integrating sowing date and nitrogen management to support precision agronomic practices and sustainable winter wheat production.
