Increasing nitrogen use efficiency of corn in midwestern cropping systems

Area of Science:

• Agricultural Science
• Soil Science
• Environmental Science

Background:

• Nitrogen (N) loss from agricultural systems poses environmental risks.
• Interactions between crop water use, N application, and soil types are poorly understood.
• Corn (Zea mays L.) production is a major agricultural system with significant N inputs.

Purpose of the Study:

• To quantify the interactions among crop water use, N application rates, and soil types in corn production.
• To evaluate the impact of these interactions on yield, N use efficiency (NUE), and water use efficiency (WUE).
• To identify management strategies for improving NUE and WUE in different soil types.

Main Methods:

• Field study conducted in central Iowa on the Clarion-Nicollet-Webster soil association.
• Quantified seasonal water use, N application rates, and yield in production-size corn fields.
• Analyzed plant growth patterns, precipitation data, and daily water use in relation to soil types and N rates.

Main Results:

• Seasonal water use varied significantly with soil type and N application rate.
• Corn yield was highest at 100 kg N ha(-1), but NUE and WUE decreased with increasing N rates.
• Low organic matter soils experienced water deficits during grain filling, leading to lower yields and increased N loss.
• Low NUE and increased drainage in low organic matter soils contributed to greater N loss.

Conclusions:

• Soil type critically influences water availability and N dynamics in corn production.
• Optimizing N application rates and considering soil water-holding capacity is essential for maximizing NUE and WUE.
• Coupling water use patterns with N application strategies can enhance both WUE and NUE, mitigating environmental N losses.