Managing Density Stress to Close the Maize Yield Gap

Area of Science:

• Agronomy and Crop Science
• Agricultural Engineering

Background:

• Maize (Zea mays L.) yield increases are crucial for food security.
• Higher planting populations are necessary but can induce stress, necessitating optimized agronomic inputs.

Purpose of the Study:

• To evaluate the individual and cumulative impacts of various agronomic factors on maize productivity.
• To identify key factors for alleviating density-induced stress and enhancing yield in maize-soybean rotations.

Main Methods:

• An incomplete factorial design assessed row spacing (0.76 vs. 0.51 m), plant population, P-S-Zn fertility, K-B fertility, N fertility, and foliar protection.
• Thirteen trials were conducted in Illinois, USA (2014-2018), comparing enhanced and standard management controls.
• Yield data was analyzed for impacts on grain yield, kernel number, and kernel weight.

Main Results:

• Enhanced management with 0.51 m rows yielded 3.3 Mg ha^-1 (25%) more grain than standard 0.76 m rows, highlighting a significant yield gap.
• Narrow rows and combined P-S-Zn/K-B fertility provided the most substantial yield increases.
• Increasing plant population enhanced yield only when all other inputs were optimized; narrow rows and nutrition were critical at higher densities.

Conclusions:

• Optimized agronomic management, particularly narrow rows and comprehensive fertility, is essential for maximizing maize yield.
• The full benefits of high-input strategies are realized when combined with increased plant density.
• Agronomic factors become more critical in mitigating density stress as plant populations increase.