Optimizing Planting Density and Nitrogen Application Enhances Root Lodging Resistance and Yield via Improved...

Area of Science:

• Agronomy
• Crop Physiology
• Plant Breeding

Background:

• Optimizing nitrogen (N) application and planting density is crucial for maximizing crop yields and lodging resistance.
• Understanding the underlying agronomic mechanisms is essential for effective crop management.

Purpose of the Study:

• To investigate the intricate relationships between canopy light distribution, photosynthetic capacity, root architecture, yield, and lodging resistance in sweet corn.
• To elucidate how nitrogen levels and planting densities influence these key agronomic traits.

Main Methods:

• A two-year field experiment utilized a split-plot design with varying nitrogen application rates (150 kg/ha and 200 kg/ha) and planting densities (20, 25, and 30 cm spacing).
• Measurements included light interception, photosynthetic capacity, root architecture, stem strength, lodging rates, and yield.

Main Results:

• Lower nitrogen application (150 kg/ha) enhanced basal stem node strength and root architecture compared to higher rates (200 kg/ha).
• Improved light interception in the lower canopy under N150 led to an 80.82% reduction in root lodging.
• Increasing planting density was the primary driver of yield improvement, with the N150D20 group achieving the highest yields (~29 t/ha).

Conclusions:

• Coordinated nitrogen input and planting density optimize vertical light distribution, strengthening plant structures and improving lodging resistance and yield.
• These findings provide practical strategies for high sweet corn yield and guidance for breeding "smart canopy" varieties.