Improving Winter Wheat Photosynthesis, Nitrogen Use Efficiency, and Yield by Optimizing Nitrogen Fertilization.

Area of Science:

• Agricultural Science
• Agronomy
• Crop Physiology

Background:

• Winter wheat (Triticum aestivum L.) is a crucial crop in China, ranking third in production.
• Enhancing nitrogen use efficiency (NUE) and grain yield is vital for sustainable agriculture.
• Optimizing nitrogen application timing and ratios can significantly impact crop performance.

Purpose of the Study:

• To investigate the effects of different nitrogen (N) doses and application ratios on winter wheat growth, physiology, and yield.
• To determine the optimal N strategy for maximizing NUE and grain yield in winter wheat.
• To analyze the relationship between nitrogen uptake, physiological parameters, and yield.

Main Methods:

• A two-year field experiment was conducted using five N doses (0-300 kg ha⁻¹) and two N ratios (50%:50% and 60%:40%) applied at various growth stages.
• Measurements included plant height, above-ground biomass (ABG), leaf area, photosynthetic rate, and nitrogen uptake.
• Correlation analysis was performed to link nitrogen parameters with physiological and yield outcomes.

Main Results:

• A nitrogen dose of 225 kg ha⁻¹ with a 60%:40% ratio significantly increased plant height (+27%), ABG (+24%), and leaf area (+149%).
• The N225 kg ha⁻¹ dose enhanced photosynthetic rates by 47% at jointing and flowering stages.
• Positive correlations were observed between nitrogen uptake, chlorophyll content, dry biomass, and ultimately, winter wheat yield.

Conclusions:

• Optimizing nitrogen application to 225 kg ha⁻¹ with a 60%:40% ratio, applied at sowing and jointing stages, significantly enhances winter wheat grain yield.
• This N management strategy improves nitrogen utilization rate and overall crop productivity.
• The findings provide valuable insights for efficient nitrogen management in winter wheat cultivation.