Corn Yield and Profitability Improved with Subsurface Drip Irrigation in the Mid-Atlantic United States

With the global population projected to reach 11.2 billion by 2100, enhancing maize yields through efficient irrigation and nutrient management is crucial for reducing yield gaps and ensuring food security. Subsurface drip irrigation (SDI) offers a promising alternative to traditional, less efficient methods. This three-year study (2022-2024) employed a split-split-plot design to evaluate optimal SDI strategies, including six dripline spacings (0.91-meter dripline, 1.82-meter dripline, and 0.91-meter + volumetric water content (VWC) sensors; 0.91-meter + fertigation, 1.82-meter + fertigation (2022), and 0.91-meter + Pivot Bio® (2023 and 2024); and non-irrigated (control)), four seeding rates (59,280 to 103,740 plants ha^-1), and four nitrogen (N) rates (133 to 333 kg N ha^-1). Data analysis revealed significant irrigation, N application, and seeding rates on grain yield, and irrigation by N rates interactions each year. Yearly irrigation impact on yield was 102%, 13%, and 51% over non-irrigated in 2022, 2023, and 2024, respectively. The 0.91-meter dripline averaged the greatest revenue ($985 ha^-1) over non-irrigated. The 0.91-meter dripline + VWC Sensor showed the strongest relationship between N rates and grain yield in 2022 (R² = 0.997), while the 0.91-meter dripline + Pivot Bio had the greatest effect in 2023 (R² = 0.998) and 2024 (R² = 1.000). These findings highlight SDI's effectiveness in increasing maize yield and profitability, reducing production risks in Virginia and the Mid-Atlantic region. The study shows the potential of targeted irrigation and nutrient management to maximize maize yields.