High-yield maize with large net energy yield and small global warming intensity

Area of Science:

• Agricultural Science
• Environmental Science
• Agronomy

Background:

• Future food security and climate change necessitate agricultural practices that enhance land productivity while minimizing environmental harm.
• Intensive agricultural systems, particularly maize cultivation, face scrutiny regarding their energy balance and greenhouse gas (GHG) emissions.

Purpose of the Study:

• To evaluate the energy balance and GHG emissions of irrigated maize production in Nebraska under high nitrogen (N) fertilizer and water inputs.
• To compare the environmental performance of these intensive irrigated systems with previous maize studies.

Main Methods:

• Analysis of on-farm data for irrigated maize systems in central Nebraska.
• Quantification of energy inputs, grain and net energy yields, and GHG emissions (CO2e).
• Assessment of N and water use efficiencies and their correlation with environmental outcomes.

Main Results:

• High inputs (183 kg N·ha⁻¹, 272 mm water) resulted in high grain and net energy yields (13.2 Mg·ha⁻¹, 159 GJ·ha⁻¹).
• GHG emission intensity was low (231 kg CO2e·Mg⁻¹ grain), outperforming lower-yielding systems.
• Variability in energy use and GHG emissions was linked to irrigation and N input management, indicating optimization potential.

Conclusions:

• Intensive irrigated maize systems can achieve high yields and energy production with reduced GHG emission intensity.
• Optimizing irrigation and N fertilizer management is crucial for further environmental performance improvements.
• High productivity, positive energy balance, and low GHG emissions are achievable simultaneously in intensive cropping systems.